WorldWideScience

Sample records for injection molding process

  1. Bubble growth in mold cavities during microcellular injection molding processes

    International Nuclear Information System (INIS)

    Bubble nucleation and growth are the key steps in polymer foam generation processes. The mechanical properties of foam polymers are closely related to the size of the bubbles created inside the material, and most existing analysis methods use a constant viscosity and surface tension to predict the size of the bubbles. Under actual situations, however, when the polymer contains gases, changes occur in the viscosity and surface tension that cause discrepancies between the estimated and observed bubble sizes. Therefore, we developed a theoretical framework to improve our bubble growth rate and size predictions, and experimentally verified our theoretical results using an injection molding machine modified to make microcellular foam products

  2. Rapid control of mold temperature during injection molding process

    International Nuclear Information System (INIS)

    The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution

  3. Rapid control of mold temperature during injection molding process

    Science.gov (United States)

    Liparoti, Sara; Hunag, Tsang Min; Sorrentino, Andrea; Titomanlio, Giuseppe; Cakmak, Mukerrem

    2015-05-01

    The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.

  4. Rapid control of mold temperature during injection molding process

    Energy Technology Data Exchange (ETDEWEB)

    Liparoti, Sara; Titomanlio, Giuseppe [Department of Industrial Engineering, University of Salerno Via Giovanni Paolo II, 132, 84084 Fisciano (Italy); Hunag, Tsang Min; Cakmak, Mukerrem [Department of Polymer Engineering, The University of Akron, Akron, OH 44325 (United States); Sorrentino, Andrea [Institute for Polymers, Composite and Biomaterials (IPCB) - CNR, P. Enrico Fermi 1, 80055 Portici (Italy)

    2015-05-22

    The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.

  5. Process and part filling control in micro injection molding

    DEFF Research Database (Denmark)

    Tosello, Guido; Hansen, Hans NØrgaard

    2008-01-01

    The influence of process parameters on ?-injection molding (?IM) and on ?-injection molded parts has been investigated using Design of Experiments. A mold with a sensor applied at injection location was used to monitor actual injection pressure and to determine the cavity filling time. Flow markers position was measured on the polymer ?-parts to evaluate filling behavior of the polymer melt flowing through ?-features. Experimental results obtained under different processing conditions were evaluated to correlate the process parameter levels influence on the selected responses. Results showed that the injection speed in one of the most influencing process parameters on the ?IM process and on the ?-parts filling.

  6. The effect of mold surface topography on plastic parat in-process shrinkage in injection molding

    DEFF Research Database (Denmark)

    Arlø, Uffe Rolf; Hansen, Hans Nørgaard; Kjær, Erik Michael

    2003-01-01

    An experimental study of the effect of mold surface roughness on in-process in-flow linear part shrinkage in injection molding has been carried out. The investigation is based on an experimental two-cavity tool, where the cavities have different surface topographies, but are otherwise identical....... The study has been carried out for typical commercial polystyrene and polypropylene grades. The relationship between mold surface topography and linear shrinkage has been investigated with an experimental two-cavity mold producing simple rectangular parts with the nominal dimensions 1 x 25 x 50 mm...

  7. Development of the computer-aided process planning (CAPP) system for polymer injection molds manufacturing

    OpenAIRE

    J. Tepi?; V. Todi?; Luki?, D.; Miloševi?, M.; S. Borojevi?

    2011-01-01

    Beginning of production and selling of polymer products largely depends on mold manufacturing. The costs of mold manufacturing have significant share in the final price of a product. The best way to improve and rationalize polymer injection molds production process is by doing mold design automation and manufacturing process planning automation. This paper reviews development of a dedicated process planning system for manufacturing of the mold for injection molding, which integrates computer-...

  8. Direct processing of continuous fibers onto injection molding machines

    Science.gov (United States)

    Truckenmueller, F. M.

    1993-06-01

    A new injection molding process 'DIF' (Direct Incorporation of Continuous Fibers) is proposed whereby roving strands are directly incorporated into the polymer melt by using a reciprocating-screw-plasticating unit. The DIF-technology offers the possibility to substitute the relatively expensive pultrusion process which is used to produce long fiber pellets. Furthermore it can be used as a fast and flexible R&D tool. In order to improve fiber dispersion with minimum fiber breakage a new mixing non-return-valve 'LFMR' (Long Fiber Mixing Ring) was developed based on the 'Twente Mixing Ring'; Its mixing capacity and influence on processing characteristics, fiber breakage and property profile of the injection molded parts is examined and compared to a general purpose non-return-valve of the ring type. The results of fundamental mechanical and physical property investigations are presented including dispersion of fiber clusters and bundles, fiber length distribution and fiber orientation.

  9. The effect of mold surface topography on plastic parat in-process shrinkage in injection molding

    DEFF Research Database (Denmark)

    ArlØ, Uffe Rolf; Hansen, Hans NØrgaard

    2003-01-01

    An experimental study of the effect of mold surface roughness on in-process in-flow linear part shrinkage in injection molding has been carried out. The investigation is based on an experimental two-cavity tool, where the cavities have different surface topographies, but are otherwise identical. The study has been carried out for typical commercial polystyrene and polypropylene grades. The relationship between mold surface topography and linear shrinkage has been investigated with an experimental two-cavity mold producing simple rectangular parts with the nominal dimensions 1 x 25 x 50 mm (see figure 1). The cavities have different surface topographies on one side, but are otherwise identical (see discussion of other contribution factors).

  10. Gate design in injection molding of microfluidic components using process simulations

    DEFF Research Database (Denmark)

    Marhöfer, D. M.; Tosello, G.; Islam, A.; Hansen, H. N.

    2015-01-01

    Just as in conventional injection molding of plastics, process simulations are an effective tool in the area of micro injection molding. They are applied in order to optimize and aid the design of the micro plastic part, the mold and the actual process. Available simulation software is actually made for macroscopic injection molding, but by means of the correct implementation and modelling strategy it can also be applied to micro plastic parts, as it is shown in the presented work. Process simul...

  11. Development of the computer-aided process planning (CAPP system for polymer injection molds manufacturing

    Directory of Open Access Journals (Sweden)

    J. Tepi?

    2011-10-01

    Full Text Available Beginning of production and selling of polymer products largely depends on mold manufacturing. The costs of mold manufacturing have significant share in the final price of a product. The best way to improve and rationalize polymer injection molds production process is by doing mold design automation and manufacturing process planning automation. This paper reviews development of a dedicated process planning system for manufacturing of the mold for injection molding, which integrates computer-aided design (CAD, computer-aided process planning (CAPP and computer-aided manufacturing (CAM technologies.

  12. Characterization of polymeric binders for Metal Injection Molding (MIM) process

    Science.gov (United States)

    Adames, Juan M.

    The Metal Injection Molding (MIM) process is an economically attractive method of producing large amounts of small and complex metallic parts. This is achieved by combining the productivity of injection molding with the versatility of sintering of metal particulates. In MIM, the powdered metal is blended with a plastic binder to obtain the feedstock. The binder imparts flowability to the blend at injection molding conditions and strength at ambient conditions. After molding, the binder is removed in a sequence of steps that usually involves solvent-extraction and polymer burn-out. Once the binder is removed, the metal particles are sintered. In this research several topics of the MIM process were studied to understand how the polymeric binder, similar to the one used in the sponsoring company, works. This was done by examining the compounding and water debinding processes, the rheological and thermal properties, and the microstructure of the binder/metal composite at different processing stages. The factors studied included the metal contents, the composition of the binder and the processing conditions. The three binders prepared during the course of this research were blends of a polyolefin, polyoxymethylene copolymer (POM) and a water-soluble polymer (WSP). The polyolefin resins included polypropylene (PP), high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). The powdered metal in the feedstocks was 316 L stainless steel. The compounding studies were completed in an internal mixer under different conditions of temperature, rotational speed and feedstock composition. It was found that the metal concentration was the most important factor in determining the torque evolution curves. The observation of microstructure with Scanning Electron Microscope (SEM) at different stages during compounding revealed that the metal particles neither agglomerate nor touch each other. The liquid extraction of the water-soluble polymer (WSP) from the molded parts (or water debinding) was investigated using two configurations of flow of water relative to the samples. Both permitted the reduction of the mass transfer resistance outside the parts, revealing information on the diffusion of the WSP inside the part exclusively. The debinding studies showed that a single effective diffusivity could be used to model the extraction process of the binder from molded parts. This approach is more accurate when the debinding time is above 2 hours. Steady shear and dynamic experiments were conducted on the binder and feedstocks samples containing LLDPE. The results of both experiments revealed that the feedstocks did not show yield stress even though the highest metal content was 64% by volume. Therefore, it was concluded that there were only hydrodynamic interactions between the metal particles. The thermal characterization of binders, polymers and feedstocks included differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The DSC tests were performed after preheating and quenching of the samples. The heating rate was 20°C/min. The TGA scans were conducted from room temperature to 700°C at 20°C/min. The DSC tests revealed that the melting point of the polymers depressed when blended in the binders and feedstocks. The depression was more intense for POM and the water-soluble polymer than for the polyolefins. Therefore, it was concluded that the melting point depression of POM and the water-soluble polymer was caused by their entrapment in the polyolefin matrix and in between the metal particles. The TGA scans showed that the feedstocks with higher metal concentration had higher final decomposition temperature, but similar onset temperature. The reason was that the higher the metal concentration the more difficult the diffusion of the products of the decomposition of the binder out of the samples. The morphological studies revealed that the binders were heterogeneous showing domains of the polar resins, embedded in a continuous phase composed of polyolefin. This distribution of phases was the result of th

  13. Process control and product evaluation in micro molding using a screwless/two-plunger injection unit

    DEFF Research Database (Denmark)

    Tosello, Guido; Hansen, Hans Nørgaard; Dormann, B.; Decker, C.; Guerrier, Patrick

    2010-01-01

    A newly developed ?-injection molding machine equipped with a screwless/two-plunger injection unit has been employed to mould miniaturized dog-bone shaped specimens on polyoxymethylene and its process capability and robustness have been analyzed. The influence of process parameters on ?-injection molding was investigated using the Design of Experiments technique. Injection pressure and piston stroke speed as well as part weight and dimensions were considered as quality factors over a wide range ...

  14. The Elastic Mold Deformation During the Filling and Packing Stage of the Injection Molding Process

    OpenAIRE

    Stefan Kleindel; Roland Eder; Herwig Schretter; Christoph Hochenauer

    2014-01-01

    The accurate numerical prediction of the mold filling process of long and thin walled parts is dependent on numerous factors. This paper investigates the effect of various influencing variables on the filling pattern by means of simulation and experimental validation. It was found that mold temperature, process settings and venting conditions have little effect on the predicted filling pattern. However, in the actual case study, the filling behavior observed during the experiments was signifi...

  15. RECENT METHODS FOR OPTIMIZATION OF PLASTIC INJECTION MOLDING PROCESS –A RETROSPECTIVE AND LITERATURE REVIEW

    Directory of Open Access Journals (Sweden)

    P.K. Bharti

    2010-09-01

    Full Text Available Injection molding has been a challenging process for many manufacturers and researchers to produce products meeting requirements at the lowest cost. Faced with global competition in injection molding industry, using the trialand- error approach to determine the process parameters for injection molding is no longer good enough. Factors that affect the quality of a molded part can be classified into four categories: part design, mold design, machineperformance and processing conditions. The part and mold design are assumed as established and fixed. During production, quality characteristics may deviate due to drifting or shifting of processing conditions caused by machine wear, environmental change or operator fatigue. Determining optimal process parameter settings critically influences productivity, quality, and cost of production in the plastic injection molding (PIM industry. Previously, production engineers used either trial-and-error method or Taguchi’s parameter design method to determine optimal process parameter settings for PIM. However, these methods are unsuitable in present PIM because of the increasing complexity of product design and the requirement of multi-response quality characteristics. This article aims to review the recent research in designing and determining process parameters of injection molding. A number of research works based on various approaches have been performed in the domain of the parameter setting for injection molding. These approaches, including mathematical models, Taguchi method, Artificial Neural Networks (ANN,Fuzzy logic, Case Based Reasoning (CBR, Genetic Algorithms (GA, Finite Element Method(FEM,Non Linear Modeling, Response Surface Methodology, Linear Regression Analysis ,Grey Rational Analysis and Principle Component Analysis (PCA are described in this article. The strength and theweakness of individual approaches are discussed. It is then followed by conclusions and discussions of the potential research in determining process parameters for injection molding.

  16. Validation of precision powder injection molding process simulations using a spiral test geometry

    DEFF Research Database (Denmark)

    Marhöfer, Maximilian; Müller, Tobias; Tosello, Guido; Islam, Aminul; Hansen, Hans N.; Piotter, Volker

    2015-01-01

    precision powder injection molding for the production of metallic and ceramic micro parts raises more and more interest though. Consequently, in the entire field the demand for simulation tools increases constantly, too. The present work reports the material characterization of feedstocks which are used for......Like in many other areas of engineering, process simulations find application in precision injection molding to assist and optimize the quality and design of precise products and the molding process. Injection molding comprises mainly the manufacturing of plastic components. However, the variant of...... powder injection molding. This characterization includes measurements of rheological, thermal, and pvT behavior of the powder-binder-mixes. The acquired material data was used to generate new material models for the database of the commercially available Autodesk Moldflow® simulation software. The...

  17. Mathematical modeling of the in-mold coating process for injection-molded thermoplastic parts

    Science.gov (United States)

    Chen, Xu

    In-Mold Coating (IMC) has been successfully used for many years for exterior body panels made from compression molded Sheet Molding Compound (SMC). The coating material is a single component reactive fluid, designed to improve the surface quality of SMC moldings in terms of functional and cosmetic properties. When injected onto a cured SMC part, IMC cures and bonds to provide a pain-like surface. Because of its distinct advantages, IMC is being considered for application to injection molded thermoplastic parts. For a successful in mold coating operation, there are two key issues related to the flow of the coating. First, the injection nozzle should be located such that the thermoplastic substrate is totally covered and the potential for air trapping is minimized. The selected location should be cosmetically acceptable since it most likely will leave a mark on the coated surface. The nozzle location also needs to be accessible for easy of maintenance. Secondly, the hydraulic force generated by the coating injection pressure should not exceed the available clamping tonnage. If the clamping force is exceeded, coating leakage will occur. In this study, mathematical models for IMC flow on the compressible thermoplastic substrate have been developed. Finite Difference Method (FDM) is first used to solve the 1 dimensional (1D) IMC flow problem. In order to investigate the application of Control Volume based Finite Element Method (CV/FEM) to more complicated two dimensional IMC flow, that method is first evaluated by solving the 1D IMC flow problem. An analytical solution, which can be obtained when a linear relationship between the coating thickness and coating injection pressure is assumed, is used to verify the numerical results. The mathematical models for the 2 dimensional (2D) IMC flow are based on the generalized Hele-Shaw approximation. It has been found experimentally that the power law viscosity model adequately predicts the rheological behavior of the coating. The compressibility of the substrate is modeled by the 2-domain Tait PVT equation. CV/FEM is used to solve the discretized governing equations. A computer code has been developed to predict the fill pattern of the coating and the injection pressure. A number of experiments have been conducted to verify the numerical predictions of the computer code. It has been found both numerically and experimentally that the substrate thickness plays a significant role on the IMC fill pattern.

  18. Process control and product evaluation in micro molding using a screwless/two-plunger injection unit

    DEFF Research Database (Denmark)

    Tosello, Guido Technical University of Denmark,

    2010-01-01

    A newly developed ?-injection molding machine equipped with a screwless/two-plunger injection unit has been employed to mould miniaturized dog-bone shaped specimens on polyoxymethylene and its process capability and robustness have been analyzed. The influence of process parameters on ?-injection molding was investigated using the Design of Experiments technique. Injection pressure and piston stroke speed as well as part weight and dimensions were considered as quality factors over a wide range of process parameters. Experimental results obtained under different processing conditions were evaluated to correlate the process parameter levels influence on the selected responses, considering both average values and standard deviations.

  19. Dimensional Accuracy Optimization of the Micro-plastic Injection Molding Process Using the Taguchi Design Method

    Directory of Open Access Journals (Sweden)

    Chil-Chyuan KUO

    2015-07-01

    Full Text Available Plastic injection molding is an important field in manufacturing industry because there are many plastic products that are produced by injection molding. However, the time and cost required for producing a precision mold are the most troublesome problems that limit the application at the development stage of a new product in precision machinery industry. This study presents an approach of manufacturing a hard mold with microfeatures for micro-plastic injection molding. This study also focuses on Taguchi design method for investigating the effect of injection parameters on the dimensional accuracy of Fresnel lens during plastic injection molding. It was found that the dominant factor affecting the microgroove depth of Fresnel lens is packing pressure. The optimum processing parameters are packing pressure of 80 MPa, melt temperature of 240 °C, mold temperature of 90 °C and injection speed of 50 m/s. The dimensional accuracy of Fresnel lens can be controlled within ±3 ?m using the optimum level of process parameters through the confirmation test. The research results of this study have industrial application values because electro-optical industries are able to significantly reduce a new optical element development cycle time.

  20. Experimental Investigation into Suitable Process Conditions for Plastic Injection Molding of Thin-Sheet Parts

    Directory of Open Access Journals (Sweden)

    Dyi-Cheng Chen

    2014-04-01

    Full Text Available This study performs an experimental investigation into the effects of the process parameters on the surface quality of injection molded thin-sheet thermoplastic components. The investigations focus specifically on the shape, number and position of the mold gates, the injection pressure and the injection rate. It can be seen that the gravity force entering point improved filling of the cavity for the same forming time and injection pressure. Moreover, it shows the same injection pressure and packing time, the taper-shape gate yields a better surface appearance than the sheet-shape gate. The experimental results provide a useful source of reference in suitable the process conditions for the injection molding of thin-sheet plastic components.

  1. Microcellular Injection Molding Using Helium

    International Nuclear Information System (INIS)

    In comparison with conventional foaming process microcellular injection molding process has advantages such as small bubble size, the removal of sink mark, scale reliability, and weight lightening. So microcellular injection molded parts are applied to electrical product and automobile part. Conventional microcellular foaming process used carbon dioxide and nitrogen as a foaming agent. And it has been never researched and applied about microcellular injection molding process using helium. In this paper, we did a microcellular injection molding process using helium based on previous research result and made samples. From this we can certificate the possibility of microcellular continuous process using helium. Helium is lighter and faster in diffusion than carbon dioxide or nitrogen so through this technique, it can be solved the problem such as spray or labeling

  2. Injection Molding of High Aspect Ratio Nanostructures

    DEFF Research Database (Denmark)

    Matschuk, Maria; Larsen, Niels Bent

    We present a process for injection molding of 40 nm wide and >100 nm high pillars (pitch: 200 nm). We explored the effects of mold coatings and injection molding conditions on the replication quality of nanostructures in cyclic olefin copolymer. We found that optimization of molding parameters...

  3. Comparative analysis of different process simulation settings of a micro injection molded part featuring conformal cooling

    DEFF Research Database (Denmark)

    Marhöfer, D. M.; Tosello, G.; Hansen, H. N.

    Process simulations are applied in all fields of engineering in order to support and optimize the design and quality of products and their manufacturing processes. Micro injection molding is not an exception in this regard. Simulations enable to investigate the process and the part quality. In the...... different simulation models are established: a version including the part without the surrounding mold block, an advanced version including the mold block and conventional cooling channels, and a third version alike the second with additional conformal cooling for efficient thermal management. The...

  4. Injection molding in biodegradable plastics

    Energy Technology Data Exchange (ETDEWEB)

    Kandachar, P.; Reijnhoudt, J.; Koster, R.; Goedhart, I. [Delft Univ. of Technol. (Netherlands). Fac. of Design, Eng. and Production

    2000-07-01

    An exploratory investigation was conducted to establish the importance of injection molding conditions for mechanical behavior of two biodegradable thermoplastics. Tensile test results are reported from specimens with 2 mm and 4 mm wall thicknesses, as well as a 2 mm thick specimen with a cold flow weld line. One of the challenges in injection molding with these materials was a limitation to the process window because of narrow margins for melt plasticizing temperatures, pressures and screw rotation rates. The results show that mold filling pressure and melt front speed have a strong effect on tensile behavior, particularly on strain at yield or break. (orig.)

  5. Injection Molding of High Aspect Ratio Nanostructures

    DEFF Research Database (Denmark)

    Matschuk, Maria; Larsen, Niels Bent

    We present a process for injection molding of 40 nm wide and >100 nm high pillars (pitch: 200 nm). We explored the effects of mold coatings and injection molding conditions on the replication quality of nanostructures in cyclic olefin copolymer. We found that optimization of molding parameters using native nickel molds only lead to slight improvements in replication quality. In contrast, a fluorocarbon based antistiction coating (FDTS) was found to improve the replication quality significantly.

  6. Injection Molding of High Aspect Ratio Nanostructures

    OpenAIRE

    Matschuk, Maria; Larsen, Niels Bent

    2012-01-01

    We present a process for injection molding of 40 nm wide and >100 nm high pillars (pitch: 200 nm). We explored the effects of mold coatings and injection molding conditions on the replication quality of nanostructures in cyclic olefin copolymer. We found that optimization of molding parameters using native nickel molds only lead to slight improvements in replication quality. In contrast, a fluorocarbon based antistiction coating (FDTS) was found to improve the replication qu...

  7. Development of Metal Plate with Internal Structure Utilizing the Metal Injection Molding (MIM Process

    Directory of Open Access Journals (Sweden)

    Kwangho Shin

    2013-12-01

    Full Text Available In this study, we focus on making a double-sided metal plate with an internal structure, such as honeycomb. The stainless steel powder was used in the metal injection molding (MIM process. The preliminary studies were carried out for the measurement of the viscosity of the stainless steel feedstock and for the prediction of the filling behavior through Computer Aided Engineering (CAE simulation. PE (high density polyethylene (HDPE and low density polyethylene (LDPE and polypropylene (PP resins were used to make the sacrificed insert with a honeycomb structure using a plastic injection molding process. Additionally, these sacrificed insert parts were inserted in the metal injection mold, and the metal injection molding process was carried out to build a green part with rectangular shape. Subsequently, debinding and sintering processes were adopted to remove the sacrificed polymer insert. The insert had a suitable rigidity that was able to endure the filling pressure. The core shift analysis was conducted to predict the deformation of the insert part. The 17-4PH feedstock with a low melting temperature was applied. The glass transition temperature of the sacrificed polymer insert would be of a high grade, and this insert should be maintained during the MIM process. Through these processes, a square metal plate with a honeycomb structure was made.

  8. LCI Databases Sensitivity Analysis of the Environmental Impact of the Injection Molding Process

    Directory of Open Access Journals (Sweden)

    Ana Elduque

    2015-03-01

    Full Text Available During the last decades, society’s concern for the environment has increased. Specific tools like the Life Cycle Assessment (LCA, and software and databases to apply this method have been developed to calculate the environmental burden of products or processes. Calculating the environmental impact of plastic products is relevant as the global plastics production rose to 288 million tons in 2012. Among the different ways of processing plastics, the injection molding process is one of the most used in the industry worldwide. In this paper, a sensitivity analysis of the environmental impact of the injection molding process has been carried out. In order to perform this study, the EcoInvent database inventory for injection molding, and the data from which this database is created, have been studied. Generally, when an LCA of a product is carried out, databases such as EcoInvent, where materials, processes and transports are characterized providing average values, are used to quantify the environmental impact. This approach can be good enough in some cases but in order to assess a specific production process, like injection molding, a further level of detail is needed. This study shows how the final results of environmental impact differ for injection molding when using the PVC’s, PP’s or PET’s data. This aspect suggests the necessity of studying, in a more precise way, this process, to correctly evaluate its environmental burden. This also allows us to identify priority areas and thereby actions to develop a more sustainable way of manufacturing plastics.

  9. Injection Molding of Plastics from Agricultural Materials

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, M.; Ruan, R.

    2001-02-22

    The objective of this research was to conduct a systematic study to relate injection molding parameters to properties of blends of starch and synthetic polymer. From this study, we wished to develop a thorough understanding of the injection molding process and gain significant insight into designing molds and aiding in developing products cheaply and efficiently.

  10. The effects of process parameters on injection-molded PZT ceramics part fabrication- compounding process rheology.

    Energy Technology Data Exchange (ETDEWEB)

    Halbleib, Laura L.; Yang, Pin; Mondy, Lisa Ann; Burns, George Robert

    2005-05-01

    Solid solutions of lead-based perovskites are the backbone materials of the piezoelectric components for transducer, actuator, and resonator applications. These components, typically small in size, are fabricated from large sintered ceramic slugs using grinding and lapping processes. These operations increase manufacturing costs and produce a large hazardous waste stream, especially when component size decreases. To reduce costs and hazardous wastes associated with the production of these components, an injection molding technique is being investigated to replace the machining processes. The first step in the new technique is to compound an organic carrier with a ceramic powder. The organic carrier is a thermoplastic based system composed of a main carrier, a binder, and a surfactant. Understanding the rheology of the compounded material is necessary to minimize the creation of defects such as voids or cavities during the injection-molding process. An experiment was performed to model the effects of changes in the composition and processing of the material on the rheological behavior. Factors studied included: the surfactant of the organic carrier system, the solid loading of the compounded material, and compounding time. The effects of these factors on the viscosity of the material were investigated.

  11. Gate design in injection molding of microfluidic components using process simulations

    DEFF Research Database (Denmark)

    Marhöfer, David Maximilian; Tosello, Guido; Islam, Aminul; Hansen, Hans Nørgaard

    design with regard to moulding process window, polymer flow, and part quality. This finally led to an optimization of the design and the realization as actual steel mold. Additionally, the simulation results were critically discussed and possible improvements and limitations of the gained results and the......Process simulations are an effective design and optimization tool in conventional as well as micro injection molding (μIM). They can be applied to optimize and assist the design of the micro part, the mold, the micro cavity and the μIM process. Available simulation software is however developed for...... macroscopic plastic parts. By using the correct implementation and careful modelling though, it can also be applied to micro parts. In the present work, process simulations were applied to a microfluidic distributor and a microfluidic mixer of which features were in the 100 μm dimensional range. The meshing...

  12. On Optimization of Injection Molding Cooling

    OpenAIRE

    Rännar, Lars-Erik

    2008-01-01

    This thesis is devoted to analysis and optimization of the injection molding process with a focus on the mold. In the analysis, both process parameters and the design of the mold are taken in consideration. A procedure has been developed, i.e. a method and a program code, which enables optimization of different quantities, not only restricted to injection molding simulation, by altering different variables. There are many ways to interpret the word “optimization”. In this work, “optimization”...

  13. Experimental validation of viscous and viscoelastic simulations of micro injection molding process

    DEFF Research Database (Denmark)

    Gava, Alberto; Tosello, Guido; Lucchetta, Giovanni; Hansen, Hans Nørgaard; Schoth, Andreas

    2009-01-01

    The effects of two different rheological models used in the simulation of the micro injection molding (µIM) process are investigated. The Cross-WLF viscous model and the Giesekus viscoelastic model are selected and their performance evaluated using 3D models implemented on two different commercially available software packages. Simulation results are then compared with the experimental µIM process. Validation parameters for the comparison are the flow front position during filling of the micro c...

  14. Two component tungsten powder injection molding – An effective mass production process

    Energy Technology Data Exchange (ETDEWEB)

    Antusch, Steffen, E-mail: steffen.antusch@kit.edu; Commin, Lorelei; Mueller, Marcus; Piotter, Volker; Weingaertner, Tobias

    2014-04-01

    Tungsten and tungsten-alloys are presently considered to be the most promising materials for plasma facing components for future fusion power plants. The Karlsruhe Institute of Technology (KIT) divertor design concept for the future DEMO power plant is based on modular He-cooled finger units and the development of suitable mass production methods for such parts was needed. A time and cost effective near-net-shape forming process with the advantage of shape complexity, material utilization and high final density is Powder Injection Molding (PIM). This process allows also the joining of two different materials e.g. tungsten with a doped tungsten alloy, without brazing. The complete technological process of 2-Component powder injection molding for tungsten materials and its application on producing real DEMO divertor parts, characterization results of the finished parts e.g. microstructure, hardness, density and joining zone quality are discussed in this contribution.

  15. Two component tungsten powder injection molding – An effective mass production process

    International Nuclear Information System (INIS)

    Tungsten and tungsten-alloys are presently considered to be the most promising materials for plasma facing components for future fusion power plants. The Karlsruhe Institute of Technology (KIT) divertor design concept for the future DEMO power plant is based on modular He-cooled finger units and the development of suitable mass production methods for such parts was needed. A time and cost effective near-net-shape forming process with the advantage of shape complexity, material utilization and high final density is Powder Injection Molding (PIM). This process allows also the joining of two different materials e.g. tungsten with a doped tungsten alloy, without brazing. The complete technological process of 2-Component powder injection molding for tungsten materials and its application on producing real DEMO divertor parts, characterization results of the finished parts e.g. microstructure, hardness, density and joining zone quality are discussed in this contribution

  16. Optimization of plastic injection molding process parameters for manufacturing a brake booster valve body

    International Nuclear Information System (INIS)

    Highlights: • PIM process parameters have been optimized for a brake booster valve body. • The Taguchi method and computer-aided engineering have been integrated and used. • Seven key parameters of PIM process have been considered. • A nearly 12% improvement have been found by using the optimal PIM process parameters. • The efficient improvement can improve the safety performance of a vehicle. - Abstract: The plastic injection molding (PIM) process parameters have been investigated for manufacturing a brake booster valve body. The optimal PIM process parameters is determined with the application of computer-aided engineering integrating with the Taguchi method to improve the compressive property of the valve body. The parameters considered for optimization are the following: number of gates, gate size, molding temperature, resin temperature, switch over by volume filled, switch over by injection pressure, and curing time. An orthogonal array of L18 is created for the statistical design of experiments based on the Taguchi method. Then, Mold-Flow analyses are performed by using the designed process parameters based on the L18 orthogonal array. The signal-to-noise (S/N) ratio and the analysis of variance (ANOVA) are used to find the optimal PIM process parameters and to figure out the impact of the viscosity of resin, curing percentage, and compressive strength on a brake booster valve body. When compared with the average compression strength out of the 18 design experiments, the compression strength of the valve body produced using the optimal PIM process parameters showed a nearly 12% improvement

  17. Automatic polishing process of plastic injection molds on a 5-axis milling center

    OpenAIRE

    Pessoles, Xavier; Tournier, Christophe

    2010-01-01

    The plastic injection mold manufacturing process includes polishing operations when surface roughness is critical or mirror effect is required to produce transparent parts. This polishing operation is mainly carried out manually by skilled workers of subcontractor companies. In this paper, we propose an automatic polishing technique on a 5-axis milling center in order to use the same means of production from machining to polishing and reduce the costs. We develop special algorithms to compute...

  18. Multi-scale filling simulation of micro-injection molding process

    International Nuclear Information System (INIS)

    This work proposes a multi-scale simulation method that can simulate filling during the micro-injection molding process. The multiscale simulation is comprised of two steps. In the first step, the macro-scale flow is analyzed using the conventional method. In the second step, the micro-scale simulation is conducted taking the slip and surface tension into consideration to investigate the filling of microcavity. Moreover, a conservative level set method is employed to accurately track the flow front. First, numerical tests have been done for circular micro-channels. The results show that slip and surface tension play important roles in the micro-regime. Second, to verify the multi-scale method, filling of a thin plate with micro-channel patterns has been simulated. The results show that the proposed multi-scale method is promising for micro-injection molding simulations

  19. Functional nanostructures on injection molded plastic

    DEFF Research Database (Denmark)

    Johansson, Alicia Charlotte; Søgaard, Emil; Andersen, Nis Korsgaard; Sun, Ling; Taboryski, Rafael J.

    Nanotechnology can be used to make inexpensive plastic parts with functional surfaces. The plastic parts can be molded using a standard injection molding process. The nanostructures are directly transferred from the surface of the molding tool to the surface of the molded plastic part during the...... molding process. The main advantage with this method is that surface treatments and chemical additives are avoided, which minimizes health risks and simplifies recycling. Another advantage is that the unique technology enables nanostructuring of free form molded parts. The functional surfaces can have...

  20. Process development of injection molded parts with wound fiber structures for local reinforcement

    Science.gov (United States)

    Heinzle, V.; Huber, T.; Henning, F.; Elsner, P.

    2014-05-01

    Glass and carbon fiber reinforcements in injection molded parts have been used for many decades in combination with thermoplastics. Where short- or long-fiber pellets are used, all areas of the part are nearly equally reinforced by fibers. With local continuous-fiber reinforcements it is possible to reduce fiber usage to the most highly loaded areas of the components along the lines of flux. This method, which draws on principles applied in nature, strengthens the parts with only a slight weight increase compared to non-reinforced parts. The combination of injection molding as a process for large-scale production with the high mechanical properties of continuous-fiber-reinforcements enables the production of high-strength components at reasonable costs. The paper presents the investigation of a process development with injection molded components in combination with wound fiber structures. Fundamental experiments with tensile loaded wound fiber structures regarding to their design influences are presented. On this basis a reinforcement structure for a demonstrator was developed and examined.

  1. Investigation of process parameters for an Injection molding component for warpage and Shrinkage

    Directory of Open Access Journals (Sweden)

    Mohammad Aashiq M1 , Arun A.P1 ,Parthiban M

    2013-04-01

    Full Text Available The purpose of the research is to explore the influence of different mold temperatures on the warpage & shrinkage of the injection molded component’s. The simulation software MOLDEX 3D was used for this study, the simulations were done by varying different mold temperatures and their corresponding warpage & shrinkage were collected. It was found that the different mold wall temperature causes the asymmetrical polymer flow in the cross-section due to which the asymmetrical structure in the parts cross-section occurs and this was observed using the flow analysis software. So it is required to assurehomogeneous mold wall temperature across the entire cavityduring the production of injection molded parts. This researchfinally concludes that warpage and shrinkage decreases for increased values of mold temperature

  2. Optimizing Injection Molding Processing Parameters for Enhanced Mechanical Performance of Oil Palm Empty Fruit Bunch High Density Polyethylene Composites

    OpenAIRE

    M. S. Ramli; M.R. Abdul Latif; P.S.M. Megat-Yusoff

    2011-01-01

    This study reports on the influence of injection molding processing parameters on mechanical properties of oil palm Empty Fruit Bunch (EFB) filled High Density Poly Ethylene (HDPE). The biocomposite pellets were first prepared using an extruder with 20 wt% EFB content before being processed in an injection-molding machine for specimen fabrication. Two processing parameters were varied systematically and independently during the composite sample fabrication. The holding pressure was increased ...

  3. Modeling of the flow continuum and optimal design of control-oriented injection systems in liquid composite molding processes

    Science.gov (United States)

    Gokce, Ali

    Several methodologies are presented in this dissertation that aim to ensure successful filling of the mold cavity consistently, during the mold filling stage of Liquid Composite Molding (LCM) processes such as Resin Transfer Molding (RTM), Vacuum Assisted Resin Transfer Molding (VARTM) and Seemann Composites Resin Infusion Molding (SCRIMP). Key parameters that affect the resin flow in the mold cavity can be divided into two main groups as continuum-related parameters and injection-related parameters. Flow continuum, which consists of all the spaces resin can reach in the mold cavity, has two major components: the porous medium, which is made up of the fiber reinforcements, and the flow channels that are introduced into the flow continuum unintentionally and offer an easy flow path to the resin. The properties that characterize the porous medium and the unintentional flow channels are continuum-related parameters. The injection-related parameters include resin injection locations (gates), resin injection conditions and air drainage locations (vents). Modeling the flow continuum is crucial in predicting the resin flow in the mold cavity. In this study, permeability, the key property of the porous medium, is predicted using the Method of Cells, a proven method to predict macroscopic properties of heterogeneous materials. Unintentional flow channels, which are also called racetracking channels, are modeled using a probabilistic approach. Injection-related parameters are the key tools to influence the resin flow in the mold cavity. In this study, Branch and Bound Search is modified for single gate optimization. Due to its pertinence to injection system design, the parameters that govern gate effectiveness in steering the resin advance are studied. A combinatorial search algorithm is proposed for vent optimization. Vent optimization and gate optimization algorithms are integrated for simultaneous gate and vent optimization. Overall, these methodologies reduce the cycle time and reject ratio of LCM processes by providing an accurate and complete model of the flow continuum and optimal control-oriented injection design solutions, increasing the profitability and feasibility of the process.

  4. Gate/Runner Optimization of Injection Molding Process Using Micro Genetic Algorithm

    International Nuclear Information System (INIS)

    A traditional mold design has been conducted by experience-based trial and error, whereby the mold designer would decide the gate locations based on the caring characteristics and its functional requirements. The paper suggests an optimal runner system in the injection molding using a global search method referred to as micro genetic algorithm(? GA). ? GA yields the optimal solution with a small size of population without respect to design variables for saving time that is needed to calculate the fitness of many individuals. Due to the reason, the paper uses ? GA with a commercial analysis package of injection molding(CAPA) to optimize runner system

  5. Numerical approach of the injection molding process of fiber-reinforced composite with considering fiber orientation

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Thi, T. B., E-mail: thanhbinh.skku@gmail.com, E-mail: yokoyama@kit.ac.jp; Yokoyama, A., E-mail: thanhbinh.skku@gmail.com, E-mail: yokoyama@kit.ac.jp [Department of Advanced Fibro-Science, Kyoto Institute of Technology (Japan); Ota, K., E-mail: kei-ota@toyobo.jp, E-mail: katsuhiro-kodama@toyobo.jp, E-mail: katsuhisa-yamashita@toyobo.jp, E-mail: yumiko-isogai@toyobo.jp, E-mail: kenji-furuichi@toyobo.jp, E-mail: chisato-nonomura@toyobo.jp; Kodama, K., E-mail: kei-ota@toyobo.jp, E-mail: katsuhiro-kodama@toyobo.jp, E-mail: katsuhisa-yamashita@toyobo.jp, E-mail: yumiko-isogai@toyobo.jp, E-mail: kenji-furuichi@toyobo.jp, E-mail: chisato-nonomura@toyobo.jp; Yamashita, K., E-mail: kei-ota@toyobo.jp, E-mail: katsuhiro-kodama@toyobo.jp, E-mail: katsuhisa-yamashita@toyobo.jp, E-mail: yumiko-isogai@toyobo.jp, E-mail: kenji-furuichi@toyobo.jp, E-mail: chisato-nonomura@toyobo.jp; Isogai, Y., E-mail: kei-ota@toyobo.jp, E-mail: katsuhiro-kodama@toyobo.jp, E-mail: katsuhisa-yamashita@toyobo.jp, E-mail: yumiko-isogai@toyobo.jp, E-mail: kenji-furuichi@toyobo.jp, E-mail: chisato-nonomura@toyobo.jp; Furuichi, K., E-mail: kei-ota@toyobo.jp, E-mail: katsuhiro-kodama@toyobo.jp, E-mail: katsuhisa-yamashita@toyobo.jp, E-mail: yumiko-isogai@toyobo.jp, E-mail: kenji-furuichi@toyobo.jp, E-mail: chisato-nonomura@toyobo.jp; Nonomura, C., E-mail: kei-ota@toyobo.jp, E-mail: katsuhiro-kodama@toyobo.jp, E-mail: katsuhisa-yamashita@toyobo.jp, E-mail: yumiko-isogai@toyobo.jp, E-mail: kenji-furuichi@toyobo.jp, E-mail: chisato-nonomura@toyobo.jp [Toyobo Co., LTD. Research Center (Japan)

    2014-05-15

    One of the most important challenges in the injection molding process of the short-glass fiber/thermoplastic composite parts is being able to predict the fiber orientation, since it controls the mechanical and the physical properties of the final parts. Folgar and Tucker included into the Jeffery equation a diffusive type of term, which introduces a phenomenological coefficient for modeling the randomizing effect of the mechanical interactions between the fibers, to predict the fiber orientation in concentrated suspensions. Their experiments indicated that this coefficient depends on the fiber volume fraction and aspect ratio. However, a definition of the fiber interaction coefficient, which is very necessary in the fiber orientation simulations, hasn't still been proven yet. Consequently, this study proposed a developed fiber interaction model that has been introduced a fiber dynamics simulation in order to obtain a global fiber interaction coefficient. This supposed that the coefficient is a sum function of the fiber concentration, aspect ratio, and angular velocity. The proposed model was incorporated into a computer aided engineering simulation package C-Mold. Short-glass fiber/polyamide-6 composites were produced in the injection molding with the fiber weight concentration of 30 wt.%, 50 wt.%, and 70 wt.%. The physical properties of these composites were examined, and their fiber orientation distributions were measured by micro-computed-tomography equipment ?-CT. The simulation results showed a good agreement with experiment results.

  6. Application of knowledge-based vision to closed-loop control of the injection molding process

    Science.gov (United States)

    Marsh, Robert; Stamp, R. J.; Hill, T. M.

    1997-10-01

    An investigation is under way to develop a control system for an industrial process which uses a vision systems as a sensor. The research is aimed at the improvement of product quality in commercial injection molding system. A significant enhancement has been achieved in the level of application of visually based inspection techniques to component quality. The aim of the research has been the investigation, and employment, of inspection methods that use knowledge based machine vision. The application of such techniques in this context is comprehensive, extending from object oriented analysis, design and programming of the inspection program, to the application of rule based reasoning, to image interpretation, vision system diagnostics, component diagnostics and molding machine control. In this way, knowledge handling methods are exploited wherever they prove to be beneficial. The vision knowledge base contains information on the procedures required to achieve successful identification of component surface defects. A collection of image processing and pattern recognition algorithms are applied selectively. Once inspection of the component has been performed, defects are related to process variables which affect the quality of the component, and another knowledge base is used to effect a control action at the molding machine. Feedback from other machine sensor is also used to direct the control procedure. Results from the knowledge based vision inspection system are encouraging. They indicate that rapid and effective fault detection and analysis is feasible, as is the verification of system integrity.

  7. Influence of process parameters on the weld lines of a micro injection molded component

    DEFF Research Database (Denmark)

    Tosello, Guido; Gava, Alberto

    2007-01-01

    The insufficient entanglement of the molecular chains and the stress amplification at the v-notch of a weld line compromise the mechanical strength of a plastic product, also in the micro scale. To investigate the influence of process parameters on the weld lines formation, a special micro cavity was designed and manufactured by µEDM (Electro Discharge Machining). Weld lines were quantitatively characterized both in the two-dimensional (direction and position) and three-dimensional range (surface topography characterization). Results showed that shape and position of weld lines are mainly influenced by mold temperature and injection speed.

  8. Optimization of injection molding process for car fender in consideration of energy efficiency and product quality

    Directory of Open Access Journals (Sweden)

    Hong Seok Park

    2014-10-01

    Full Text Available Energy efficiency is an essential consideration in sustainable manufacturing. This study presents the car fender-based injection molding process optimization that aims to resolve the trade-off between energy consumption and product quality at the same time in which process parameters are optimized variables. The process is specially optimized by applying response surface methodology and using nondominated sorting genetic algorithm II (NSGA II in order to resolve multi-object optimization problems. To reduce computational cost and time in the problem-solving procedure, the combination of CAE-integration tools is employed. Based on the Pareto diagram, an appropriate solution is derived out to obtain optimal parameters. The optimization results show that the proposed approach can help effectively engineers in identifying optimal process parameters and achieving competitive advantages of energy consumption and product quality. In addition, the engineering analysis that can be employed to conduct holistic optimization of the injection molding process in order to increase energy efficiency and product quality was also mentioned in this paper.

  9. Hydrogen silsesquioxane mold coatings for improved replication of nanopatterns by injection molding

    DEFF Research Database (Denmark)

    Hobæk, Thor Christian; Matschuk, Maria; Kafka, Jan; Pranov, Henrik J.; Larsen, Niels Bent

    2015-01-01

    We demonstrate the replication of nanosized pillars in polymer (cyclic olefin copolymer) by injection molding using nanostructured thermally cured hydrogen silsesquioxane (HSQ) ceramic coatings on stainless steel mold inserts with mold nanostructures produced by a simple embossing process. At...

  10. Injection molded superhydrophobic surfaces based on microlithography and black silicon processing

    DEFF Research Database (Denmark)

    Søgaard, Emil; Andersen, Nis Korsgaard; Taboryski, Rafael; Smistrup, Kristian

    2012-01-01

    This work is concerned with the design, development, and testing of nanostructured polymer surfaces with self-cleaning properties that can be manufactured by injection molding. In particular, the superimposed micro- and nanometer length scales of the so-called Lotus effect were investigated in detail with an engineering perspective on choice of materials and manufacturability by injection molding. Microscope slides with superhydrophobic properties were succesfully fabricated. Preliminary results...

  11. Study of soft magnetic iron cobalt based alloys processed by powder injection molding

    Science.gov (United States)

    Silva, Aline; Lozano, Jaime A.; Machado, Ricardo; Escobar, Jairo A.; Wendhausen, Paulo A. P.

    As a near net shape process, powder injection molding (PIM) opens new possibilities to process Fe-Co alloys for magnetic applications. Due to the fact that PIM does not involve plastic deformation of the material during processing, we envisioned the possibility of eliminating vanadium (V), which is generally added to Fe-Co alloys to improve the ductility in order to enable its further shaping by conventional processes such as forging and cold rolling. In our investigation we have found out two main futures related to the elimination of V, which lead to a cost-benefit gain in manufacturing small magnetic components where high-saturation induction is needed at low frequencies. Firstly, the elimination of V enables the achievement of much better magnetic properties when alloys are processed by PIM. Secondly, a lower sintering temperature can be used when the alloy is processed starting with elemental Fe and Co powders without the addition of V.

  12. Optimizing Injection Molding Processing Parameters for Enhanced Mechanical Performance of Oil Palm Empty Fruit Bunch High Density Polyethylene Composites

    Directory of Open Access Journals (Sweden)

    M.S. Ramli

    2011-01-01

    Full Text Available This study reports on the influence of injection molding processing parameters on mechanical properties of oil palm Empty Fruit Bunch (EFB filled High Density Poly Ethylene (HDPE. The biocomposite pellets were first prepared using an extruder with 20 wt% EFB content before being processed in an injection-molding machine for specimen fabrication. Two processing parameters were varied systematically and independently during the composite sample fabrication. The holding pressure was increased from 60 to 90 bars while the injection temperature was varied from 150 to 210°C. The highest tensile strength of the composites was achieved at 70 bar holding pressure and 150°C injection temperature. However, the highest fracture strength was achieved at 80 bars whilst maintaining the injection temperature at 150°C. Flexural strength was shown to be unaffected by the varying pressure. The optimal processing parameters for highest mechanical performance were found to be at holding pressure of 80 bars and injection tempera

  13. Experimental validation of viscous and viscoelastic simulations of micro injection molding process

    DEFF Research Database (Denmark)

    Gava, Alberto; Tosello, Guido

    2009-01-01

    The effects of two different rheological models used in the simulation of the micro injection molding (µIM) process are investigated. The Cross-WLF viscous model and the Giesekus viscoelastic model are selected and their performance evaluated using 3D models implemented on two different commercially available software packages. Simulation results are then compared with the experimental µIM process. Validation parameters for the comparison are the flow front position during filling of the micro cavity. They are respectively obtained by applying the short-shots method and the flow-markers method. The µIM part is a polystyrene tensile bar test weighting 20mg and with three µ-features 300µm wide.

  14. Injection molded superhydrophobic surfaces based on microlithography and black silicon processing

    DEFF Research Database (Denmark)

    SØgaard, Emil; Andersen, Nis Korsgaard

    2012-01-01

    This work is concerned with the design, development, and testing of nanostructured polymer surfaces with self-cleaning properties that can be manufactured by injection molding. In particular, the superimposed micro- and nanometer length scales of the so-called Lotus effect were investigated in detail with an engineering perspective on choice of materials and manufacturability by injection molding. Microscope slides with superhydrophobic properties were succesfully fabricated. Preliminary results indicate a contact angle increase from 95° for the unstructured polymer to a maximum 150°. The lowest drop roll off angles observed were in the range 1° to 5°.

  15. All polymer, injection molded nanoslits, fabricated through two-level UV-LIGA processes

    DEFF Research Database (Denmark)

    Østergaard, Peter Friis; Matteucci, Marco; Marie, Rodolphe; Kristensen, Anders; Taboryski, Rafael J.

    Micro- and nanofluidic systems fabricated in silicon and glass substrates are expensive and have long production cycles. To minimize the time used by researchers to fabricate their systems, rather than using them, medium to high volume throughput of specific chips, containing fluidic channels in...... the micro- and nanoregime is required. To obtain this, injection molding is included in the research process for making several chips (100-1000) with the same layout. The time it takes for the individual chip to be fabricated in this way is much shorter than with conventional cleanroom methods, and...... the price is equally lower. Optimization of the final chip is explored, by looking at which aspects ratios are possible to obtain in polymer chips. Finally, signal to noise ratio of the chips used for fluorescent experiments is investigated, by an expected reduction of the excitation of fluorescent...

  16. All polymer, injection molded nanoslits, fabricated through two-level UV-LIGA processes

    DEFF Research Database (Denmark)

    Østergaard, Peter Friis; Matteucci, Marco

    2012-01-01

    Micro- and nanofluidic systems fabricated in silicon and glass substrates are expensive and have long production cycles. To minimize the time used by researchers to fabricate their systems, rather than using them, medium to high volume throughput of specific chips, containing fluidic channels in the micro- and nanoregime is required. To obtain this, injection molding is included in the research process for making several chips (100-1000) with the same layout. The time it takes for the individual chip to be fabricated in this way is much shorter than with conventional cleanroom methods, and the price is equally lower. Optimization of the final chip is explored, by looking at which aspects ratios are possible to obtain in polymer chips. Finally, signal to noise ratio of the chips used for fluorescent experiments is investigated, by an expected reduction of the excitation of fluorescent states in the polymer with the use of chips in different colors.

  17. Functional nanostructures on injection molded plastic

    DEFF Research Database (Denmark)

    Johansson, Alicia Charlotte; SØgaard, Emil

    Nanotechnology can be used to make inexpensive plastic parts with functional surfaces. The plastic parts can be molded using a standard injection molding process. The nanostructures are directly transferred from the surface of the molding tool to the surface of the molded plastic part during the molding process. The main advantage with this method is that surface treatments and chemical additives are avoided, which minimizes health risks and simplifies recycling. Another advantage is that the unique technology enables nanostructuring of free form molded parts. The functional surfaces can have many different properties including anti-reflective, self-cleaning, anti-stiction or color effects. In this work we focus on the superhydrophobic and self-cleaning properties.

  18. Surface microstructure replication in injection molding

    DEFF Research Database (Denmark)

    Theilade, Uffe ArlØ; Hansen, Hans NØrgaard

    2006-01-01

    In recent years, polymer components with surface microstructures have been in rising demand for applications such as lab-on-a-chip and optical components. Injection molding has proven to be a feasible and efficient way to manufacture such components. In injection molding, the mold surface topography is transcribed onto the plastic part through complex mechanisms. This replication, however, is not perfect, and the replication quality depends on the plastic material properties, the topography itself, and the process conditions. This paper describes and discusses an investigation of injection molding of surface microstructures. The fundamental problem of surface microstructure replication has been studied. The research is based on specific microstructures as found in lab-on-a-chip products and on rough surfaces generated from EDM (electro discharge machining) mold cavities. Emphasis is put on the ability to replicate surface microstructures under normal injection-molding conditions, i.e., with commodity materials within typical process windows. It was found that within typical process windows the replication quality depends significantly on several process parameters, and especially the mold temperature. For the specific microstructures, evidence suggests that step-height replication quality depends linearly on structure width in a certain range

  19. Characterization of Injection Molded Structures

    DEFF Research Database (Denmark)

    Sun, Ling; SØgaard, Emil

    Microscopy has been widely applied to understand surface structures of solid samples. According to the instrumental methodology, there are different microscopy methods: optical microscopy, electron microscopy, and scanning probe microscopy (SPM). These microscopy methods have individual advantages and limitations. Therefore, it would be difficult to characterize complex, especially hierarchical structures by using only one method. Here we present a combined optical microscopy, scanning electron microscopy (SEM), and scanning probe microscopy study on injection molded structures. These structures are used for different applications. We show how to correlate the structures of the polymer replicas with respect to their functionalities. Furthermore, we introduce how we coordinate with all partners in the “Nanoplast” project, and how we utilize the existing facilities of each method to understand structure-properties relationship of the injection molded polymer samples. These results are very important in optimizing injection molding parameters.

  20. Injection molded self-cleaning surfaces

    DEFF Research Database (Denmark)

    SØgaard, Emil

    2014-01-01

    This PhD thesis concerns the development of superhydrophobic surfaces fabricated by injection molding. Today, injection molding is the prevalent production method for consumer plastic products. However, concerns regarding the environmental impact of a plastic production are increasing, especially because the use of potentially toxic self-cleaning coatings is used worldwide in a larger and larger scale. In this context, the work in this PhD project could be seen as a scientific effort towards reducing toxic compounds in manufactured plastic parts by developing injecting molded surfaces that are superhydrophobic based on topography rather than chemical compounds. Therefore, a novel method for fabricating superhydrophobic polymer surfaces with excellent water-repellant properties is developed. The method is based on microstructure fabrication and superposed nanostructures on silicon wafers. The nano- and microstructured silicon is electroplated with nickel and the resulting nickel shim with inverse polarity is used in an injection molding process. A versatile injection molding process capable of producing different nano- and microstructures on areas larger than 10 cm2 is developed. Variotherm mold heating is used to ensure complete filling of the mold and a mold cavity-depacking process step is introduced. The depacking step increases polymer shrinkage allowing the nano- and microstructures to be successfully demolded. A systematic wetting study on injection molded polymer surfaces is performed on periodic hierarchical structures with nanograss and holes. Water wetting tests are carried out using a pressure cell to control the water pressure. Microscopic wetting behavior of the structures is studied by optical transmission microscopy. Interestingly, it is found that the surface chemistry of the polymer changes over time causing a decrease in hydrophobicity. It is concluded that the material properties of the polymer is critical for maintaining superhydrophobicity under water exposure. A range of different structures with and without the hierarchical nanograss, pillars, micro cavities (holes), spruce like micropillars and pyramid shaped structures are examined. By employing deep ultra violet (DUV) projection lithography for mold fabrication, polymer surface feature sizes in the nanometer range could be realized over large surface areas. The superhydrophobic surfaces were fabricated from the amorphous polymer TOPAS 8007-S04 (COC) and the semi crystalline polymer PP HD601CF. An overview of the different types of structures in relation to applications is given. In particular, spruce like micropillars seems interesting. Here, the contact angles increase from 102° for unstructured polymer surfaces, to 172° for structured surfaces with a drop roll-off angle of less than 2°. Thereby, it is shown that an extremely water repellant surface can be injection molded directly with clear perspectives for more environmental and healthier plastic consumer products.

  1. The research of UV curing injection molding

    Science.gov (United States)

    Xie, Pengcheng; Chang, Le; Song, Le; Cai, Tianze; Ding, Yumei; Yang, Weimin

    2015-05-01

    The micro-injection molding technology and the UV (ultraviolet) curing technique are combined to bring about a new plastic forming method, UV curing injection molding. The mean weight of micro-product is an important process characteristic for UV curing injection molding as well as the surface quality of micro-features is another important process characteristic for this new plastic forming method. This research investigates three effects of processing factors on the mass-change rate of micro-product and the surface quality of micro-features. In every particular, the following two factors are considered: UV material system temperature and the packing pressure. The study revealed that as usual, the micro-products gain weight with the imported increasing UV material system temperature and the improved packing pressure. Meanwhile, the increasing packing pressure also improves the surface quality, yet, warming the UV system temperature up has no effect on the quality of the product.

  2. Dynamic of taking out molding parts at injection molding

    Directory of Open Access Journals (Sweden)

    E. Ragan

    2012-10-01

    Full Text Available Most plastic parts used in automobile production are manufactured by injection molding. Their quality depends also on taking out molding and on the manipulators for it. Task of this contribution is to theoretically describe a transport of molding at taking out after injection molding in relation on its regulation. The following quantities are derived at it: the transition characteristic of the taking out system, the blocking diagram of taking out molding regulation, the amplitude and phase characteristic and the transition characteristic of action quantity at taking out molding regulation.

  3. Injection-Molded Long-Fiber Thermoplastic Composites: From Process Modeling to Prediction of Mechanical Properties

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep; Kunc, Vlastimil; Jin, Xiaoshi; Tucker III, Charles L.; Costa, Franco

    2013-12-18

    This article illustrates the predictive capabilities for long-fiber thermoplastic (LFT) composites that first simulate the injection molding of LFT structures by Autodesk® Simulation Moldflow® Insight (ASMI) to accurately predict fiber orientation and length distributions in these structures. After validating fiber orientation and length predictions against the experimental data, the predicted results are used by ASMI to compute distributions of elastic properties in the molded structures. In addition, local stress-strain responses and damage accumulation under tensile loading are predicted by an elastic-plastic damage model of EMTA-NLA, a nonlinear analysis tool implemented in ABAQUS® via user-subroutines using an incremental Eshelby-Mori-Tanaka approach. Predicted stress-strain responses up to failure and damage accumulations are compared to the experimental results to validate the model.

  4. Injection molding of silicon nitride

    International Nuclear Information System (INIS)

    Silicon Nitride with 9-13 vol% liquid phase, recrystallised at 1100-1400 C after sintering at 1850 C (2,5-3,5h) in a powder bed have been produced in near net shape by injection molding. During molding with a binder of polystyrene, micro wax and dispersion agents a maximum powder content of 62 vol% and 59 vol% was obtained for the the two Silicon Nitride powders (UBE, SN-ESP and HCST, S respectively). Due to microcracking during binder removal (Tmax=500 C) in atmospheric air the bending strength was low even at relative theoretical densities of 95,5%. (orig.)

  5. Injection molding of high aspect ratio sub-100 nm nanostructures

    DEFF Research Database (Denmark)

    Matschuk, Maria; Larsen, Niels B

    2013-01-01

    We have explored the use of mold coatings and optimized processing conditions to injection mold high aspect ratio nanostructures (height-to-width >1) in cyclic olefin copolymer (COC). Optimizing the molding parameters on uncoated nickel molds resulted in slight improvements in replication quality as described by height, width and uniformity of the nanoscopic features. Use of a mold temperature transiently above the polymer glass transition temperature (Tg) was the most important factor in increa...

  6. Nanostructuring steel for injection molding tools

    DEFF Research Database (Denmark)

    Al-Azawi, A.; Smistrup, Kristian

    2014-01-01

    The production of nanostructured plastic items by injection molding with ridges down to 400 nm in width, which is the smallest line width replicated from nanostructured steel shims, is presented. Here we detail a micro-fabrication method where electron beam lithography, nano-imprint lithography and ion beam etching are combined to nanostructure the planar surface of a steel wafer. Injection molded plastic parts with enhanced surface properties, like anti-reflective, superhydrophobic and structural colors can be achieved by micro-and nanostructuring the surface of the steel molds. We investigate the minimum line width that can be realized by our fabrication method and the influence of etching angle on the structure profile during the ion beam etching process. Trenches down to 400 nm in width have been successfully fabricated into a 316 type electro-polished steel wafer. Afterward a plastic replica has been produced by injection molding with good structure transfer fidelity. Thus we have demonstrated that by utilizing well-established fabrication techniques, nanostructured steel shims that are used in injection molding, a technique that allows low cost mass fabrication of plastic items, are produced.

  7. Multi-height structures in injection molded polymer

    DEFF Research Database (Denmark)

    Andersen, Nis Korsgaard; Taboryski, Rafael J.

    2015-01-01

    We present the fabrication process for injection molded multi-height surface structures for studies of wetting behavior. We adapt the design of super hydrophobic structures to the fabrication constrictions imposed by industrial injection molding. This is important since many super hydrophobic surfaces are challenging to realize by injection molding due to overhanging structures and very high aspect ratios. In the fabrication process, we introduce several unconventional steps for producing the de...

  8. Smart plastic functionalization by nanoimprint and injection molding

    DEFF Research Database (Denmark)

    Zalkovskij, Maksim; Thamdrup, Lasse Højlund; Smistrup, Kristian; Andén, Thomas; Johansson, Alicia C.; Mikkelsen, Niels Jørgen; Madsen, Morten Hannibal; Garnæs, Jørgen; Kristiansen, Tommy Tungelund; Diemer, Mads; Døssing, Michael; Minzari, Daniel; Tang, Peter Torben; Kristensen, Anders; Taboryski, Rafael J.; Essendrop, Søren; Nielsen, Theodor; Bilenberg, Brian

    2015-01-01

    In this paper, we present a route for making smart functionalized plastic parts by injection molding with sub-micrometer surface structures. The method is based on combining planar processes well known and established within silicon micro and sub-micro fabrication with proven high resolution and high fidelity with truly freeform injection molding inserts. The link between the planar processes and the freeform shaped injection molding inserts is enabled by the use of nanoimprint with flexible mol...

  9. The evaluation of vacuum venting and variotherm process for improving the replication by injection molding of high aspect ratio micro features for biomedical application

    Science.gov (United States)

    Sorgato, Marco; Lucchetta, Giovanni

    2015-05-01

    The aspect ratio achievable in replicating micro features is one of the most important process characteristics and it is a major manufacturing constraint in applying injection molding in a range of micro engineering applications. Vacuum venting has been reported to be an effective technique in replicating micro features by microinjection molding. High surface-to-volume ratio and reduced dimensions of micro parts promote the instantaneous drop of melt temperature and consequently lead to incomplete filling. This study aims to investigate the effects of variotherm process, cavity evacuation and their interaction on the production of a micro fluidic filter for biomedical applications. A low-viscosity polystyrene and a cyclic olefin copolymer were molded applying a combination of mold evacuation and a rapid mold temperature variation that keeps the cavity temperature above the glass transition temperature during the injection phase. The research revealed the importance of these molding technologies in enhancing part filling and the replication quality for high aspect ratio micro features.

  10. Influence of different process settings conditions on the accuracy of micro injection molding simulations: an experimental validation

    DEFF Research Database (Denmark)

    Tosello, Guido; Gava, Alberto

    2009-01-01

    Currently available software packages exhibit poor results accuracy when performing micro injection molding (µIM) simulations. However, with an appropriate set-up of the processing conditions, the quality of results can be improved. The effects on the simulation results of different and alternative process conditions are investigated, namely the nominal injection speed, as well as the cavity filling time and the evolution of the cavity injection pressure as experimental data. In addition, the sensitivity of the results to the quality of the rheological data is analyzed. Simulated results are compared with experiments in terms of flow front position at part and micro features levels, as well as cavity injection filling time measurements.

  11. Progress in Titanium Metal Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    Randall M. German

    2013-08-01

    Full Text Available Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and impurity level. As summarized here, recent research has isolated the four critical success factors in titanium metal powder injection molding (Ti-MIM that must be simultaneously satisfied—density, purity, alloying, and microstructure. The critical role of density and impurities, and the inability to remove impurities with sintering, compels attention to starting Ti-MIM with high quality alloy powders. This article addresses the four critical success factors to rationalize Ti-MIM processing conditions to the requirements for demanding applications in aerospace and medical fields. Based on extensive research, a baseline process is identified and reported here with attention to linking mechanical properties to the four critical success factors.

  12. A method for manufacturing a tool part for an injection molding process, a hot embossing process, a nano-imprint process, or an extrusion process

    DEFF Research Database (Denmark)

    The present invention relates to a method for manufacturing a tool part for an injection molding process, a hot embossing process, nano-imprint process or an extrusion process. First, there is provided a master structure (10) with a surface area comprising nanometre-sized protrusions (11) with a...... into a metal insert (20), the metal insert having a corresponding nanometre-sized pattern (21) from said protrusions, and thirdly, adapting the metal insert into a tool part (30) for enabling nanometre- sized patterns being formed by the tool part. The invention provides an easier and faster way of...

  13. Numerical Analysis of Mold Deformation Including Plastic Melt Flow During Injection Molding

    International Nuclear Information System (INIS)

    In the present study, a numerical analysis of an injection molding process was conducted for predicting the mold deformation considering non-Newtonian flow, heat transfer, and structural behavior. The accurate prediction of mold deformation during the filling stage is important to successfully design and manufacture a precision injection mold. While the local mold deformation can be caused by various factors, a pressure induced by the polymer melt is considered to be one of the most significant ones. In this regard, the numerical simulation considering both the melt filling and the mold deformation was carried out. A mold core for a 2D axisymmetric center-gated disk was used for the demonstration of the present study. The flow behavior inside the mold cavity and temperature distribution were analyzed along with the core displacement. Also, a Taguchi method was employed to investigate the influence of the relevant parameters including flow velocity, mold core temperature, and melt temperature

  14. Numerical Analysis of Mold Deformation Including Plastic Melt Flow During Injection Molding

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Joon Tae; Lee, Bong-Kee [Chonnam National University, Gwangju (Korea, Republic of)

    2014-07-15

    In the present study, a numerical analysis of an injection molding process was conducted for predicting the mold deformation considering non-Newtonian flow, heat transfer, and structural behavior. The accurate prediction of mold deformation during the filling stage is important to successfully design and manufacture a precision injection mold. While the local mold deformation can be caused by various factors, a pressure induced by the polymer melt is considered to be one of the most significant ones. In this regard, the numerical simulation considering both the melt filling and the mold deformation was carried out. A mold core for a 2D axisymmetric center-gated disk was used for the demonstration of the present study. The flow behavior inside the mold cavity and temperature distribution were analyzed along with the core displacement. Also, a Taguchi method was employed to investigate the influence of the relevant parameters including flow velocity, mold core temperature, and melt temperature.

  15. Surface microstructure replication in injection molding

    DEFF Research Database (Denmark)

    Theilade, Uffe Arlø; Hansen, Hans Nørgaard

    In recent years, polymer components with surface microstructures have been in rising demand for applications such as lab-on-a-chip and optical components. Injection molding has proven to be a feasible and efficient way to manufacture such components. In injection molding, the mold surface topogra...

  16. Mold

    International Nuclear Information System (INIS)

    This book consists of three parts, which explains the basic principle of making mold. The first part includes plastic mold with introduction of plastic mold, mold compression, transfer mold, injection mold, heat and cool for mold, runner and gate, making of core and cavity and preparation of mold. The second part indicates die casting mold with zinc die casting mold, aluminum die casting mold, finishing of mold. The third part gives a description of rubber mold with manufacture of rubber mold.

  17. A Fully Coupled Simulation and Optimization Scheme for the Design of 3D Powder Injection Molding Processes

    International Nuclear Information System (INIS)

    The paper is concerned with optimization and parametric identification of Powder Injection Molding process that consists first in injection of powder mixture with polymer binder and then to the sintering of the resulting powders parts by solid state diffusion. In the first part, one describes an original methodology to optimize the injection stage based on the combination of Design Of Experiments and an adaptive Response Surface Modeling. Then the second part of the paper describes the identification strategy that one proposes for the sintering stage, using the identification of sintering parameters from dilatometer curves followed by the optimization of the sintering process. The proposed approaches are applied to the optimization for manufacturing of a ceramic femoral implant. One demonstrates that the proposed approach give satisfactory results

  18. Validation of three-dimensional micro injection molding simulation accuracy

    DEFF Research Database (Denmark)

    Tosello, Guido Technical University of Denmark,

    2011-01-01

    Data analysis and simulations on micro-molding experiments have been conducted. Micro molding simulations have been executed taking into account actual processing conditions implementation in the software. Various aspects of the simulation set-up have been considered in order to improve the simulation accuracy (i.e. decrease deviations from experimental values): injection speed profile, cavity injection pressure, melt and mold temperatures, three-dimensional mesh parameters, and material rheological characterization. Quality factors investigated for the quantitative comparisons were: short shot length, injection pressure profile, molding mass and flow pattern. The importance of calibrated micro molding process monitoring for an accurate implementation strategy of the simulation and its validation has been demonstrated. In fact, inconsistencies and uncertainties in the experimental data must be minimized to avoid introducing uncertainties in the simulation calculations. Simulations of bulky sub-100 milligrams micro molded parts have been validated and a methodology for accurate micro molding simulations was established.

  19. Modelling and monitoring in injection molding

    DEFF Research Database (Denmark)

    Thyregod, Peter

    2001-01-01

    This thesis is concerned with the application of statistical methods in quality improvement of injection molded parts. The methods described are illustrated with data from the manufacturing of parts for a medical device. The emphasis has been on the variation between cavities in multi-cavity molds. >From analysis of quality measurements from a longer period of manufacturing, it was found that differences in cavities was that source of variation with greatest influence on the lenght of the molded parts. The other large contribution to the lenght varation was the different machine settings. Samples taken within the same machine set-point did not cause great variation compared to the two preceding sources of variation. A simple graphical approach is suggested for finding patterns in the cavity differences. Applying this method to data from a 16 cavity mold, a clear connection was found between a parts lenght and the producing cavitys position in the mold. In a designed expriment it was possible to isolate the machine parameters contributing to the variation beteeen cavities. Thus, with a proper choice of levels for the machine variables, it was possible to reduce the varation between cavities substantially. Also an alternative model for the shrinkage of parts from a multi-cavity mold is suggested. From applying the model to data from a shringage study, it seemed that the observed part differences were not only due to differences in cavity dimensions. A model for the in-control varation for a multi-cavity molding process was suggested. Based on this model, control charting proceures have been suggested for monitoring the quality of the molded parts. Moreover, a capability index for multi-cavity molds has been suggested. Furthermore an alternative method for in-line quality charting is suggested. The method is for continuous control by attributes, and it is an alternative to the batch oriented approach mostly used. The procedure is especially efficient for quality requirements of very low proportion non-conformities. For the proposed charts the ARL function is derived. It is shown that in the case where a non-conforning unit is only expected very rarely during sampling, a moving sum chart and a CUSUM chart are equivalent. Finally, the correlation structure of 21 process variables has been studied prior to monitoring the process. Is is illustrated how the process can be analysed with multivariate techniques. It was found that two principal components reflected changes in machine set-points. Thus, there seems to be great potential in monitoring the process variables using a multivariate approach.

  20. Injection molding of high aspect ratio sub-100 nm nanostructures

    DEFF Research Database (Denmark)

    Matschuk, Maria; Larsen, Niels B

    2013-01-01

    We have explored the use of mold coatings and optimized processing conditions to injection mold high aspect ratio nanostructures (height-to-width >1) in cyclic olefin copolymer (COC). Optimizing the molding parameters on uncoated nickel molds resulted in slight improvements in replication quality as described by height, width and uniformity of the nanoscopic features. Use of a mold temperature transiently above the polymer glass transition temperature (Tg) was the most important factor in increasing the replication fidelity. Surface coating of the nickel molds with a fluorocarbon-containing thin film (FDTS) greatly enhanced the quality of replicated features, in particular at transient mold temperatures above Tg. Injection molding using the latter mold temperature regime resulted in a bimodal distribution of pillar heights, corresponding to either full or very poor replication of the individual pillars. The poorly replicated structures on nickel molds with or without FDTS coatings all appeared fractured. We investigated the underlying mechanism in a macroscopic model system and found reduced wetting and strongly decreased adhesion of solidified COC droplets on nickel surfaces after coating with FDTS. Reduced adhesion forces are consistent with lowered friction that reduces the risk of fracturing the nanoscopic pillars during demolding. Optimized mold surface chemistry and associated injection molding conditions permitted the fabrication of square arrays of 40 nm wide and 107 nm high (aspect ratio >2.5) pillars on a 200 nm pitch.

  1. Hydrogen silsesquioxane mold coatings for improved replication of nanopatterns by injection molding

    DEFF Research Database (Denmark)

    Hobæk, Thor Christian; Matschuk, Maria

    2015-01-01

    We demonstrate the replication of nanosized pillars in polymer (cyclic olefin copolymer) by injection molding using nanostructured thermally cured hydrogen silsesquioxane (HSQ) ceramic coatings on stainless steel mold inserts with mold nanostructures produced by a simple embossing process. At isothermal mold conditions, the average pillar height increases by up to 100% and a more uniform height distribution is observed compared to a traditional metal mold insert. Thermal heat transfer simulations predict that the HSQ film retards the cooling of the polymer melt during the initial stages of replication, thus allowing more time to fill the nanoscale cavities compared to standard metal molds. A monolayer of a fluorinated silane (heptadecafluorotrichlorosilane) deposited on the mold surface reduces the mold/polymer interfacial energy to support demolding of the polymer replica. The mechanical stability of thermally cured HSQ makes it a promising material for nanopattern replication on an industrial scale without the need for slow and energy intensive variotherm processes.

  2. Surface microstructure replication in injection molding

    DEFF Research Database (Denmark)

    Theilade, Uffe Arlø; Hansen, Hans Nørgaard

    2006-01-01

    In recent years, polymer components with surface microstructures have been in rising demand for applications such as lab-on-a-chip and optical components. Injection molding has proven to be a feasible and efficient way to manufacture such components. In injection molding, the mold surface topography is transcribed onto the plastic part through complex mechanisms. This replication, however, is not perfect, and the replication quality depends on the plastic material properties, the topography itse...

  3. Hydrogen silsesquioxane mold coatings for improved replication of nanopatterns by injection molding

    DEFF Research Database (Denmark)

    Hobæk, Thor Christian; Matschuk, Maria; Kafka, Jan; Pranov, Henrik J.; Larsen, Niels Bent

    2015-01-01

    We demonstrate the replication of nanosized pillars in polymer (cyclic olefin copolymer) by injection molding using nanostructured thermally cured hydrogen silsesquioxane (HSQ) ceramic coatings on stainless steel mold inserts with mold nanostructures produced by a simple embossing process. At...... isothermal mold conditions, the average pillar height increases by up to 100% and a more uniform height distribution is observed compared to a traditional metal mold insert. Thermal heat transfer simulations predict that the HSQ film retards the cooling of the polymer melt during the initial stages of...... replication, thus allowing more time to fill the nanoscale cavities compared to standard metal molds. A monolayer of a fluorinated silane (heptadecafluorotrichlorosilane) deposited on the mold surface reduces the mold/polymer interfacial energy to support demolding of the polymer replica. The mechanical...

  4. Multi-height structures in injection molded polymer

    DEFF Research Database (Denmark)

    Andersen, Nis Korsgaard; Taboryski, Rafael J.

    2015-01-01

    We present the fabrication process for injection molded multi-height surface structures for studies of wetting behavior. We adapt the design of super hydrophobic structures to the fabrication constrictions imposed by industrial injection molding. This is important since many super hydrophobic surfaces are challenging to realize by injection molding due to overhanging structures and very high aspect ratios. In the fabrication process, we introduce several unconventional steps for producing the desired shapes, using a completely random mask pattern, exploiting the diffusion limited growth rates of different geometries, and electroforming a nickel mold from a polymer foil. The injection-molded samples are characterized by contact angle hysteresis obtained by the tilting method. We find that the receding contact angle depends on the surface coverage of the random surface structure, while the advancing contact angle is practically independent of the structure. Moreover, we argue that the increase in contact angle hysteresis correlates with the concentration of pinning sites among the random surface structures.

  5. Modelling and monitoring in injection molding

    DEFF Research Database (Denmark)

    Thyregod, Peter

    2001-01-01

    This thesis is concerned with the application of statistical methods in quality improvement of injection molded parts. The methods described are illustrated with data from the manufacturing of parts for a medical device. The emphasis has been on the variation between cavities in multi-cavity molds. >From analysis of quality measurements from a longer period of manufacturing, it was found that differences in cavities was that source of variation with greatest influence on the lenght of the molded...

  6. Nanostructuring steel for injection molding tools

    DEFF Research Database (Denmark)

    Al-Azawi, A.; Smistrup, Kristian; Kristensen, Anders

    2014-01-01

    The production of nanostructured plastic items by injection molding with ridges down to 400 nm in width, which is the smallest line width replicated from nanostructured steel shims, is presented. Here we detail a micro-fabrication method where electron beam lithography, nano-imprint lithography and...... replica has been produced by injection molding with good structure transfer fidelity. Thus we have demonstrated that by utilizing well-established fabrication techniques, nanostructured steel shims that are used in injection molding, a technique that allows low cost mass fabrication of plastic items, are...

  7. Injection molding integration of theory and modeling methods

    CERN Document Server

    Zheng, Rong; Fan, Xi-Jun

    2011-01-01

    This practical volume covers the fundamental principles and numerical methods related to modeling the injection molding process. It addresses the cutting edge of our understanding of simulation technologies, without losing sight of useful classical approaches.

  8. CENTRAL CONVEYING & AUTO FEEDING SYSTEMS FOR AN INJECTION MOLDING SHOP

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    2011-08-01

    Full Text Available Nowadays injection molding is probably the most important method of Processing of consumer and industrial goods, and is performed everywhere in the world. The developing of injection molding becomes a competition from day to day. This Process now integrated with computer control make the production better in quality and Better quantity. The trends of producing a plastics product in injection molding industries are recently changing from traditional method to using the FEA analysis. For injection molding industries, time and cost is very important aspects to consider because these two aspectswill directly related to the profits at a company. The next issue toconsider, to get the best parameter for the injection molding process, plastics has been waste. Through the experiment, operator will use large amount of plastics material to get the possibly parameters to setup the machine.To produce the parts with better quality and quantity these molding defects are the major obstacles in achieving the targets with quality & quantity. Various defects like Short shot, colour streaks and low productivity rates are associated with the material mixing and feeding as molded plastics are often a blend of two or more materials. Colors (master batch and other additives are often mixed (blended with the raw plastic material prior to the molding process in molding plants. So it is very necessary to work out auto blending and auto feeding of plasticgranules to the machine hopper. This paper will cover the studyof automatic blending unit & central conveying system for plasticgranule feeding to machine & will help in optimizing the injection molding process.

  9. Injection molding of high aspect ratio sub-100 nm nanostructures

    DEFF Research Database (Denmark)

    Matschuk, Maria; Larsen, Niels B

    2013-01-01

    as described by height, width and uniformity of the nanoscopic features. Use of a mold temperature transiently above the polymer glass transition temperature (Tg) was the most important factor in increasing the replication fidelity. Surface coating of the nickel molds with a fluorocarbon......We have explored the use of mold coatings and optimized processing conditions to injection mold high aspect ratio nanostructures (height-to-width >1) in cyclic olefin copolymer (COC). Optimizing the molding parameters on uncoated nickel molds resulted in slight improvements in replication quality...... individual pillars. The poorly replicated structures on nickel molds with or without FDTS coatings all appeared fractured. We investigated the underlying mechanism in a macroscopic model system and found reduced wetting and strongly decreased adhesion of solidified COC droplets on nickel surfaces after...

  10. Validation of three-dimensional micro injection molding simulation accuracy

    DEFF Research Database (Denmark)

    Tosello, Guido; Costa, F.S.; Hansen, Hans Nørgaard

    2011-01-01

    Data analysis and simulations on micro-molding experiments have been conducted. Micro molding simulations have been executed taking into account actual processing conditions implementation in the software. Various aspects of the simulation set-up have been considered in order to improve the...... length, injection pressure profile, molding mass and flow pattern. The importance of calibrated micro molding process monitoring for an accurate implementation strategy of the simulation and its validation has been demonstrated. In fact, inconsistencies and uncertainties in the experimental data must be...

  11. Injection molding simulation with variothermal mold temperature control of highly filled polyphenylene sulfide

    Science.gov (United States)

    Birkholz, A.; Tschiersky, M.; Wortberg, J.

    2015-05-01

    For the installation of a fuel cell stack to convert chemical energy into electricity it is common to apply bipolar plates to separate and distribute reaction gases and cooling agents. For reducing manufacturing costs of bipolar plates a fully automated injection molding process is examined. The high performance thermoplastic matrix material, polyphenylene sulfide (PPS), defies against the chemical setting and the operation temperature up to 200 °C. To adjust also high electrical and thermal conductivity, PPS is highly filled with various carbon fillers up to an amount of 65 percentage by volume. In the first step two different structural plates (one-sided) with three different gate heights and molds are designed according to the characteristics of a bipolar plate. To cope with the approach that this plate should be producible on standard injection molding machines with variothermal mold temperature control, injection molding simulation is used. Additionally, the simulation should allow to formulate a quality prediction model, which is transferrable to bipolar plates. Obviously, the basis for a precise simulation output is an accurate description of the material properties and behavior of the highly filled compound. This, the design of the structural plate and mold and the optimization via simulation is presented, as well. The influence of the injection molding process parameters, e.g. injection time, cycle times, packing pressure, mold temperature, and melt temperature on the form filling have been simulated to determine optimal process conditions. With the aid of the simulation and the variothermal mold temperature control it was possible to reduce the required melt temperature below the decomposition temperature of PPS. Thereby, hazardous decomposition products as hydrogen sulfide are obviated. Thus, the health of the processor, the longevity of the injection molding machine as well as the material and product properties can be protected.

  12. Innovative use of wood-plastic-composites (WPC) as a core material in the sandwich injection molding process

    Science.gov (United States)

    Moritzer, Elmar; Martin, Yannick

    2016-03-01

    The demand for materials based on renewable raw materials has risen steadily in recent years. With society's increasing interest for climate protection and sustainability, natural-based materials such as wood-plastic-composites (WPC) have gained market share thanks to their positive reputation. Due to advantages over unreinforced plastics such as cost reduction and weight savings it is possible to use WPC in a wide area of application. Additionally, an increase in mechanical properties such as rigidity and strength is achieved by the fibers compared to unreinforced polymers. The combination of plastic and wood combines the positive properties of both components in an innovative material. Despite the many positive properties of wood-plastic-composite, there are also negative characteristics that prevent the use of WPC in many product areas, such as automotive interiors. In particular, increased water intake, which may result in swelling of near-surface particles, increased odor emissions, poor surface textures and distortion of the components are unacceptable for many applications. The sandwich injection molding process can improve this situation by eliminating the negative properties of WPC by enclosing it with a pure polymer. In this case, a layered structure of skin and core material is produced, wherein the core component is completely enclosed by the skin component. The suitability of WPC as the core component in the sandwich injection molding has not yet been investigated. In this study the possibilities and limitations of the use of WPC are presented. The consideration of different fiber types, fiber contents, skin materials and its effect on the filling behavior are the focus of the presented analysis.

  13. Polyethylene ionomer-based nano-composite foams prepared by a batch process and MuCell injection molding

    International Nuclear Information System (INIS)

    To understand the correlation between foamability and melt rheology of polyethylene-based ionomers having different degrees of the neutralization and corresponding nano-composites, we have conducted the foam processing via a batch process in an autoclave and microcellular foam injection molding (FIM) process using the MuCell technology. We have discussed the obtainable morphological properties in both foaming processes. All cellular structures were investigated by using field emission scanning electron microscopy. The competitive phenomenon between the cell nucleation and the cell growth including the coalescence of cell was discussed in light of the interfacial energy and the relaxation rate as revealed by the modified classical nucleation theory and rheological measurement, respectively. The FIM process led to the opposite behavior in the cell growth and coalescence of cell as compared with that of the batch process, where the ionic cross-linked structure has significant contribution to retard the cell growth and coalescence of cell. The mechanical properties of the structural foams obtained by FIM process were discussed.

  14. Polyethylene ionomer-based nano-composite foams prepared by a batch process and MuCell injection molding

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Hidetomo; Mori, Tomoki [Advanced Polymeric Nanostructured Materials Engineering, Graduate School of Engineering, Toyota Technological Institute, Hisakata 2-12-1, Tempaku, Nagoya 468-8511 (Japan); Okamoto, Masami, E-mail: okamoto@toyota-ti.ac.jp [Advanced Polymeric Nanostructured Materials Engineering, Graduate School of Engineering, Toyota Technological Institute, Hisakata 2-12-1, Tempaku, Nagoya 468-8511 (Japan); Yamasaki, Satoshi; Hayami, Hiroshi [Polymer Materials Technology R and D Department Electronics and Materials R and D Laboratories, Sumitomo Electric Industries, Ltd., Shimaya, Konohana-ku, 1-1-3, Osaka, 554-0024 (Japan)

    2010-01-01

    To understand the correlation between foamability and melt rheology of polyethylene-based ionomers having different degrees of the neutralization and corresponding nano-composites, we have conducted the foam processing via a batch process in an autoclave and microcellular foam injection molding (FIM) process using the MuCell technology. We have discussed the obtainable morphological properties in both foaming processes. All cellular structures were investigated by using field emission scanning electron microscopy. The competitive phenomenon between the cell nucleation and the cell growth including the coalescence of cell was discussed in light of the interfacial energy and the relaxation rate as revealed by the modified classical nucleation theory and rheological measurement, respectively. The FIM process led to the opposite behavior in the cell growth and coalescence of cell as compared with that of the batch process, where the ionic cross-linked structure has significant contribution to retard the cell growth and coalescence of cell. The mechanical properties of the structural foams obtained by FIM process were discussed.

  15. Powder Injection Molding of Ceramic Engine Components for Transportation

    Science.gov (United States)

    Lenz, Juergen; Enneti, Ravi K.; Onbattuvelli, Valmikanathan; Kate, Kunal; Martin, Renee; Atre, Sundar

    2012-03-01

    Silicon nitride has been the favored material for manufacturing high-efficiency engine components for transportation due to its high temperature stability, good wear resistance, excellent corrosion resistance, thermal shock resistance, and low density. The use of silicon nitride in engine components greatly depends on the ability to fabricate near net-shape components economically. The absence of a material database for design and simulation has further restricted the engineering community in developing parts from silicon nitride. In this paper, the design and manufacturability of silicon nitride engine rotors for unmanned aerial vehicles by the injection molding process are discussed. The feedstock material property data obtained from experiments were used to simulate the flow of the material during injection molding. The areas susceptible to the formation of defects during the injection molding process of the engine component were identified from the simulations. A test sample was successfully injection molded using the feedstock and sintered to 99% density without formation of significant observable defects.

  16. Mechanical behavior of injection-molded starch-based polymers

    OpenAIRE

    R. L. Reis; Cunha, A. M.; Allan, P S; Bevis, M. J.

    1996-01-01

    This work evaluates the mechanical performance of injection-molded starch-based copolymers, 60/40 (mol/mol) starch/poly(ethylene vinyl alcohol), and the possibility of improving material properties through deliberately induced anisotropy during processing. Different types of samples were produced by conventional and shear-controlled injection molding (Scorim) and tested under tensile and impact loading. The behavior of three distinct grades is discussed in terms of the respective fracture mor...

  17. Design, analysis and simulation in injection in-mold labeling

    OpenAIRE

    Patcharee Larpsuriyakul

    2009-01-01

    Years ago, the production of packaging with the injection-IML has been established. This procedure concept ranks nowadays among the most modern technologies in the area of the plastic packaging. With this manufacturing technique, label and packaging, both are of the same polymer materials, become inseparably connected during the injection molding process. Since thermal conductivity of the polymeric label material is clearly smaller than that of the metal mold wall, thermal induced warpage of ...

  18. Smart plastic functionalization by nanoimprint and injection molding

    DEFF Research Database (Denmark)

    Zalkovskij, Maksim; Thamdrup, Lasse HØjlund

    2015-01-01

    In this paper, we present a route for making smart functionalized plastic parts by injection molding with sub-micrometer surface structures. The method is based on combining planar processes well known and established within silicon micro and sub-micro fabrication with proven high resolution and high fidelity with truly freeform injection molding inserts. The link between the planar processes and the freeform shaped injection molding inserts is enabled by the use of nanoimprint with flexible molds for the pattern definition combined with unidirectional sputter etching for transferring the pattern. With this approach, we demonstrate the transfer of down to 140 nm wide holes on large areas with good structure fidelity on an injection molding steel insert. The durability of the sub-micrometer structures on the inserts have been investigated by running two production series of 102,000 and 73,000 injection molded parts, respectively, on two different inserts and inspecting the inserts before and after the production series and the molded parts during the production series.

  19. A method for manufacturing a tool part for an injection molding process, a hot embossing process, a nano-imprint process, or an extrusion process

    DEFF Research Database (Denmark)

    SØgaard, Emil Technical University of Denmark,

    The present invention relates to a method for manufacturing a tool part for an injection molding process, a hot embossing process, nano-imprint process or an extrusion process. First, there is provided a master structure (10) with a surface area comprising nanometre-sized protrusions (11) with a minimum density of approximately 105 protrusions/mm2, the protrusions being positioned in a non- periodic, irregular pattern, said protrusions being created by a process comprising alternating passivation and etching into the master structure. Secondly, there is made a transfer of the master structure into a metal insert (20), the metal insert having a corresponding nanometre-sized pattern (21) from said protrusions, and thirdly, adapting the metal insert into a tool part (30) for enabling nanometre- sized patterns being formed by the tool part. The invention provides an easier and faster way of manufacturing the master structure, e.g. a black silicon wafer. It is a further advantage of the present invention that it provides an advantageous way of making tools capable of producing self-cleaning surfaces without the need for chemical coating.

  20. An Integrated Approach Linking Process to Structural Modeling With Microstructural Characterization for Injections-Molded Long-Fiber Thermoplastics

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep; Bapanapalli, Satish K.; Smith, Mark T.; Kunc, Vlastimil; Frame, Barbara; Norris, Robert E.; Phelps, Jay; Tucker III, Charles L.; Jin, Xiaoshi; Wang, Jin

    2008-09-01

    The objective of our work is to enable the optimum design of lightweight automotive structural components using injection-molded long fiber thermoplastics (LFTs). To this end, an integrated approach that links process modeling to structural analysis with experimental microstructural characterization and validation is developed. First, process models for LFTs are developed and implemented into processing codes (e.g. ORIENT, Moldflow) to predict the microstructure of the as-formed composite (i.e. fiber length and orientation distributions). In parallel, characterization and testing methods are developed to obtain necessary microstructural data to validate process modeling predictions. Second, the predicted LFT composite microstructure is imported into a structural finite element analysis by ABAQUS to determine the response of the as-formed composite to given boundary conditions. At this stage, constitutive models accounting for the composite microstructure are developed to predict various types of behaviors (i.e. thermoelastic, viscoelastic, elastic-plastic, damage, fatigue, and impact) of LFTs. Experimental methods are also developed to determine material parameters and to validate constitutive models. Such a process-linked-structural modeling approach allows an LFT composite structure to be designed with confidence through numerical simulations. Some recent results of our collaborative research will be illustrated to show the usefulness and applications of this integrated approach.

  1. Two component micro injection molding for MID fabrication

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul; Hansen, Hans Nørgaard; Tang, Peter Torben

    2009-01-01

    Molded Interconnect Devices (MIDs) are plastic substrates with electrical infrastructure. The fabrication of MIDs is usually based on injection molding and different process chains may be identified from this starting point. The use of MIDs has been driven primarily by the automotive sector, but...... recently the medical sector seems more and more interested. In particular the possibility of miniaturization of 3D components with electrical infrastructure is attractive. The paper describes possible manufacturing routes and challenges of miniaturized MIDs based on two component micro injection molding...... and subsequent metallization. The technology will be demonstrated by an industrial component....

  2. Two component micro injection molding for MID fabrication

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul; Hansen, Hans NØrgaard

    2009-01-01

    Molded Interconnect Devices (MIDs) are plastic substrates with electrical infrastructure. The fabrication of MIDs is usually based on injection molding and different process chains may be identified from this starting point. The use of MIDs has been driven primarily by the automotive sector, but recently the medical sector seems more and more interested. In particular the possibility of miniaturization of 3D components with electrical infrastructure is attractive. The paper describes possible manufacturing routes and challenges of miniaturized MIDs based on two component micro injection molding and subsequent metallization. The technology will be demonstrated by an industrial component.

  3. Injection molding of bushes made of tribological PEEK composites

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available Polyetheretherketone (PEEK composites have been extensively studied because of the excellent tribological behavior among plastics. However, laboratory specimens and tests are generally discussed, whereas application studies on industrial components are infrequent. In this paper, an injection molded bush made of tribological PEEK was analyzed to correlate wear behavior and molded material structure. Bushes were tested under unlubricated sliding conditions by means of a short wear test. Surface analysis, differential scanning calorimetry (DSC and optical microscopy were used to evaluate the distribution of the different composite fillers (polytetrafluoroethylene, PTFE, graphite particles and carbon microfibers and their effect on the final bush behavior. A significant lack of homogeneity was observed in the molded bush and black bands appeared on the shaft surface after testing due to the sliding. The bush geometry and the injection molding process should be optimized to allow the best tribological behavior of the molded material under working conditions.

  4. Residual stress distribution in injection molded parts

    Directory of Open Access Journals (Sweden)

    P. Postawa

    2006-08-01

    Full Text Available Purpose: The paper presents the results of the investigations of influence of the amorphous polystyrene (PSprocessing on the diversity of the internal stresses observed in the injection moulded piece.Design/methodology/approach: For the tests, the standardized mould piece designed for the investigations ofthe processing shrinkage of thermoplastics materials has been used. The samples have been prepared using theDesign of Experiment (DoE theory.The state of internal stresses has been analysed by means of photoelastic method (used stress viewer equipmenton the basis of the layout and size of the isochromatics (fields with the same colour, which determine the mouldpiece’s areas where the same value for the difference of main tensions. In the article the results of investigationsof influence of 5 chosen processing parameters such as injection temperature Tw, mould temperature Tf,clamping pressure pd, cooling time tch and the injection speed vw on the changes in isochromatics layout as adeterminant for diversity of internal stresses in injection moulded pieces have been presented.Findings: The performed investigations of the influence of injection conditions on the state of internal stressesreached for injection mould pieces were to determine the parameters of injection at which the achieved state ofthe stresses in the mould piece (described by the difference of main tensions will show the lowest values.Practical implications: Effects of examinations of influence of processing conditions on residual stress ininjection molded parts (presented in the article could find practical application in polymer industry, both smalland large enterprises.Originality/value: New approach to fast estimation of value of residual stresses were present in the paper.

  5. Structural development of HDPE in injection molding

    OpenAIRE

    Sousa, R.A; R. L. Reis; Cunha, A. M.; Bevis, M. J.

    2003-01-01

    This study investigated some relevant structure/properties relationships in shear-controlled orientation in injection molding (SCORIM) of high-density polyethylene (HDPE). SCORIM was used to deliberately induce a strong anisotropic character in the HDPE microstructure. Three grades with different molecular weight characteristics were molded into tensile test bars, which were subsequently characterized in terms of the mechanical behavior by tensile tests and microhardness measurements. The str...

  6. Investigating the Influence of Different Process Parameters on Shrinkage of Injection-Molded Parts

    Directory of Open Access Journals (Sweden)

    A. R. Jafarian

    2005-01-01

    Full Text Available Different models have been proposed to investigate the effects of various process parameters on shrinkage of plastic parts, which in most cases the effect of each parameter is obtained by changing one factor at a time. In this research, a simple flat model has been used and a simulation code has been developed. Then, through this simulation code, the effects of different process parameters have been investigated. This code was run for a typical thermoplastic (polycarbonate and finally, a Design Of Experiments (DOE approach was used to study the effects of multiple variables on shrinkage simultaneously.

  7. Influence of process parameters on the weld lines of a micro injection molded component

    DEFF Research Database (Denmark)

    Tosello, Guido; Gava, Alberto; Hansen, Hans Nørgaard; Lucchetta, Giovanni

    2007-01-01

    The insufficient entanglement of the molecular chains and the stress amplification at the v-notch of a weld line compromise the mechanical strength of a plastic product, also in the micro scale. To investigate the influence of process parameters on the weld lines formation, a special micro cavity was designed and manufactured by µEDM (Electro Discharge Machining). Weld lines were quantitatively characterized both in the two-dimensional (direction and position) and three-dimensional range (surfac...

  8. Injection molded self-cleaning surfaces

    DEFF Research Database (Denmark)

    Søgaard, Emil

    because the use of potentially toxic self-cleaning coatings is used worldwide in a larger and larger scale. In this context, the work in this PhD project could be seen as a scientific effort towards reducing toxic compounds in manufactured plastic parts by developing injecting molded surfaces that are...

  9. Effect of reprocessing cycles on the degradation of polypropylene copolymer filled with talc or montmorillonite during injection molding process

    International Nuclear Information System (INIS)

    Mechanical recycling of polymeric materials is a favorable technique resulting in economic and environmental benefits, especially in the case of polymers with a high production volume as the polypropylene copolymer (PP). However, recycling by reprocessing techniques can lead to thermal, mechanical or thermo-oxidative degradation that can affect the structure of the polymer and subsequently the material properties. PP filled with montmorillonite (MMT) or talc are widely produced and studied, however, its degradation reactions by reprocessing cycles are poorly studied so far. In this study, the effects of reprocessing cycles in the structure and in the properties of the PP/MMT and PP/Talc were evaluated. The samples were mixed with 5% talc or MMT Cloisite C15A in a twin-screw extrusion. After extrusion, this filled material was submitted to five reprocessing cycles through an injection molding process. In order to evaluate the changes induced by reprocessing techniques, the samples were characterized by DSC, FT-IR, Izod impact and tensile strength tests. The study showed that Young modulus, elongation at brake and Izod impact were not affected by reprocessing cycles, except when using talc. In this case, the elongation at brake reduced until the fourth cycle, showing rigidity increase. The DSC results showed that melting and crystallization temperature were not affected. A comparison of FT-IR spectra of the reprocessed indicated that in both samples, between the first and the fifth cycle, no noticeable change has occurred. Thus, there is no evidence of thermo oxidative degradation. In general, these results suggest that PP reprocessing cycles using MMT or talc does not change the material properties until the fifth cycle

  10. Effect of reprocessing cycles on the degradation of polypropylene copolymer filled with talc or montmorillonite during injection molding process

    Energy Technology Data Exchange (ETDEWEB)

    Demori, R.; Mauler, R. S., E-mail: raquel.mauler@ufrgs.br [Chemistry Institute, Federal University of Rio Grande do Sul, UFRGS, Av. Bento Gonçalves, 9500, Porto Alegre, 91501-970 (Brazil); Ashton, E.; Weschenfelder, V. F.; Cândido, L. H. A.; Kindlein, W. [Laboratory of Design LDSM, Federal University of Rio Grande do Sul, UFRGS (Brazil)

    2015-05-22

    Mechanical recycling of polymeric materials is a favorable technique resulting in economic and environmental benefits, especially in the case of polymers with a high production volume as the polypropylene copolymer (PP). However, recycling by reprocessing techniques can lead to thermal, mechanical or thermo-oxidative degradation that can affect the structure of the polymer and subsequently the material properties. PP filled with montmorillonite (MMT) or talc are widely produced and studied, however, its degradation reactions by reprocessing cycles are poorly studied so far. In this study, the effects of reprocessing cycles in the structure and in the properties of the PP/MMT and PP/Talc were evaluated. The samples were mixed with 5% talc or MMT Cloisite C15A in a twin-screw extrusion. After extrusion, this filled material was submitted to five reprocessing cycles through an injection molding process. In order to evaluate the changes induced by reprocessing techniques, the samples were characterized by DSC, FT-IR, Izod impact and tensile strength tests. The study showed that Young modulus, elongation at brake and Izod impact were not affected by reprocessing cycles, except when using talc. In this case, the elongation at brake reduced until the fourth cycle, showing rigidity increase. The DSC results showed that melting and crystallization temperature were not affected. A comparison of FT-IR spectra of the reprocessed indicated that in both samples, between the first and the fifth cycle, no noticeable change has occurred. Thus, there is no evidence of thermo oxidative degradation. In general, these results suggest that PP reprocessing cycles using MMT or talc does not change the material properties until the fifth cycle.

  11. Stability of FDTS monolayer coating on aluminum injection molding tools

    DEFF Research Database (Denmark)

    Cech, Jiri; Taboryski, Rafael J.

    2012-01-01

    The injection molding industry often employs prototype molds and mold inserts from melt spun (rapid solidification processing [1,2]) aluminum, especially for applications in optics [3,4], photonics [5] and microfludics. Prototypes are also used for verification of mold filling. The use of aluminum tools has reduced lead time (days instead of weeks) and manufacturing cost (30% of conventional mold). Moreover, for aluminum, a surface roughness (RMS) below 5 nm can be obtained with diamond machining [3,4,6]. Conventional mold coatings add cost and complexity, and coatings with thicknesses of a few microns can obliterate small features. The nanoimprint lithography community extensively uses functional monolayer coatings on silicon/SiO2 lithographic stamps [7–11]. This treatment dramatically reduces stiction, and improves yield and quality of replicated nanostructures. Here we report on a fluorinated trichloro-silane based coating deposited on aluminum or its alloys by molecular vapor deposition. Wehave tested the stability of this coating in challenging conditions of injection molding, an environment with high shear stress from the molten polymer, pressures up to 200 MPa, temperatures up to 250 ?C, and rapid thermal cycling.

  12. Residual stresses in injection molded products

    Science.gov (United States)

    Jansen, K. M. B.

    2015-12-01

    During the molding process residual stresses are formed due to thermal contraction during cooling as well as the local pressure history during solidification. In this paper a simple analytical model is reviewed which relates residual stresses, product shrinkage as well as warpage to the temperature and pressure histories during molding. Precise excimer laser layer removal measurements were performed to verify the predicted residual stress distributions. In addition, detailed shrinkage and warpage measurements on a large series of polymers and for different molding conditions were performed and are shown to compare well with the model predictions.

  13. Assessment of Current Process Modeling Approaches to Determine Their Limitations, Applicability and Developments Needed for Long-Fiber Thermoplastic Injection Molded Composites

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep; Holbery, Jim; Smith, Mark T.; Kunc, Vlastimil; Norris, Robert E.; Phelps, Jay; Tucker III, Charles L.

    2006-11-30

    This report describes the status of the current process modeling approaches to predict the behavior and flow of fiber-filled thermoplastics under injection molding conditions. Previously, models have been developed to simulate the injection molding of short-fiber thermoplastics, and an as-formed composite part or component can then be predicted that contains a microstructure resulting from the constituents’ material properties and characteristics as well as the processing parameters. Our objective is to assess these models in order to determine their capabilities and limitations, and the developments needed for long-fiber injection-molded thermoplastics (LFTs). First, the concentration regimes are summarized to facilitate the understanding of different types of fiber-fiber interaction that can occur for a given fiber volume fraction. After the formulation of the fiber suspension flow problem and the simplification leading to the Hele-Shaw approach, the interaction mechanisms are discussed. Next, the establishment of the rheological constitutive equation is presented that reflects the coupled flow/orientation nature. The decoupled flow/orientation approach is also discussed which constitutes a good simplification for many applications involving flows in thin cavities. Finally, before outlining the necessary developments for LFTs, some applications of the current orientation model and the so-called modified Folgar-Tucker model are illustrated through the fiber orientation predictions for selected LFT samples.

  14. Injection molding of coarse 316L stainless steel powder

    International Nuclear Information System (INIS)

    Metal injection molding (MIM) process using 316L stainless steel powder of 45 ?m was investigated. The binder system consists of a major fraction of palm stearins and minor fraction of polyethylene with a powder loading of 65 vol. %. The rheological behaviour of the feedstock was determined using Capillary Rheometer. The feedstock then injected using vertical injection molding machine into the tensile test bar. Then molded parts were de bound and sintered in vacuum at temperature of 1360 degree Celsius. The results show that the viscosity of the feedstock decreased with the temperature increased. The best sintered density achieved was about 7.5 g/cm3 with the tensile strength of more than 460 MPa. The properties of the sintered specimens could be increased with the increasing of sintering temperature. (author)

  15. Orientation of Carbon Fibers in Copper matrix Produced by Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    Irfan Shirazi M.

    2014-07-01

    Full Text Available Fiber orientation is a big challenge in short fiber reinforced composites. Powder injection molding (PIM process has some intrinsic fiber alignment associated with it. During PIM process fibers in skin region of moldings are aligned as these regions experience higher shear flow caused by the mold walls. Fibers in the core region remain randomly aligned as these regions are far from mold walls and experience lesser shear flow. In this study short carbon fiber (CF reinforced copper matrix composite was developed by PIM process. Two copper composite feedstock formulations were prepared having 5 vol% and 10 vol% CFs and a wax based binder system. Fiber orientation was controlled during injection molding by using a modified mold that has a diverging sprue. The sprue creates converging flow when feedstock enters into the mold cavity. Fiber orientation was analysed after molding using FESEM. The orientation of fibers can be controlled by controlling flow of feedstock into the mold.

  16. Effect of starch types on properties of biodegradable polymer based on thermoplastic starch process by injection molding technique

    Directory of Open Access Journals (Sweden)

    Yossathorn Tanetrungroj

    2015-04-01

    Full Text Available In this study effects of different starch types on the properties of biodegradable polymer based on thermoplastic starch (TPS were investigated. Different types of starch containing different contents of amylose and amylopectin were used, i.e. cassava starch, mungbean starch, and arrowroot starch. The TPS polymers were compounded and shaped using an internal mixer and an injection molding machine, respectively. It was found that the amount of amylose and amylopectin contents on native starch influence the properties of the TPS polymer. A high amylose starch of TPMS led to higher strength, hardness, degree of crystallization than the high amylopectin starch of TPCS. In addition, function group analysis by Fourier transforms infrared spectrophotometer, water absorption, and biodegradation by soil burial test were also examined.

  17. Packing parameters effect on injection molding of polypropylene nanostructured surfaces

    DEFF Research Database (Denmark)

    Calaon, Matteo; Tosello, Guido; Hansen, Hans Nørgaard; Ravn, C.; Islam, Aminul

    2012-01-01

    having a diameter of 500 nm was employed. The tool insert surface was produced using chemical-based-batch techniques such aluminum anodization and nickel electroplating. During the injection molding process, polypropylene (PP) was employed as material and packing phase parameters (packing time, packing...

  18. Influence of different process settings conditions on the accuracy of micro injection molding simulations: an experimental validation

    DEFF Research Database (Denmark)

    Tosello, Guido; Gava, Alberto; Hansen, Hans Nørgaard; Reinecke, Holger; Lucchetta, Giovanni; Schoth, Andreas

    process conditions are investigated, namely the nominal injection speed, as well as the cavity filling time and the evolution of the cavity injection pressure as experimental data. In addition, the sensitivity of the results to the quality of the rheological data is analyzed. Simulated results are...

  19. Microstructural and mechanical characterization of injection molded 718 superalloy powders

    Energy Technology Data Exchange (ETDEWEB)

    Özgün, Özgür [Bingol University, Faculty of Engineering and Architecture, Mechanical Eng. Dep., 12000 Bingol (Turkey); Gülsoy, H. Özkan, E-mail: ogulsoy@marmara.edu.tr [Marmara University, Technology Faculty, Metallurgy and Materials Eng. Dep., 34722 Istanbul (Turkey); Y?lmaz, Ramazan [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey); F?nd?k, Fehim [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey) and International University of Sarajevo, Faculty of Engineering and Natural Sciences, Department of Mechanical Engineering, 71000 Sarajevo, Bosnia and Herzegovina (Bosnia and Herzegowina)

    2013-11-05

    Highlights: •Microstructural and mechanical properties of injection molded Nickel 718 superalloy were studied. •The maximum sintered density achieved this study was 97.3% at 1290 °C for 3 hours. •Tensile strength of 1022 MPa and elongation of 5.3% were achieved for sintered-heat treated samples. -- Abstract: This study concerns with the determination of optimum production parameters for injection molding 718 superalloy parts. And at the same time, microstructural and mechanical characterization of these produced parts was also carried out. At the initial stage, 718 superalloy powders were mixed with a multi-component binder system for preparing feedstock. Then the prepared feedstock was granulated and shaped by injection molding. Following this operation, the shaped samples were subjected to the debinding process. These samples were sintered at different temperatures for various times. Samples sintered under the condition that gave way to the highest relative density (3 h at 1290 °C) were solution treated and aged respectively. Sintered, solution treated and aged samples were separately subjected to microstructural and mechanical characterization. Microstructural characterization operations such as X-ray diffraction, optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and elemental analysis showed that using polymeric binder system led to plentiful carbide precipitates to be occurred in the injection molded samples. It is also observed that the volume fractions of the intermetallic phases (?? and ??) obtained by aging treatment were decreased due to the plentiful carbide precipitation in the samples. Mechanical characterization was performed by hardness measurements and tensile tests.

  20. Comparison of two setups for induction heating in injection molding

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano; Guerrier, Patrick; Tang, Peter Torben

    To eliminate defects and improve the quality of molded parts, increasing the mold temperature is one of the applicable solutions. A high mold temperature can increase the path flow of the polymer inside the cavity allowing reduction of the number of injection points, reduction of part thickness, ...

  1. Evaluation of stability for monolayer injection molding tools coating

    DEFF Research Database (Denmark)

    Cech, Jiri; Taboryski, Rafael J.

    We tested and characterized molecular coating of Aluminium and Nickel prototype molds and mold inserts for polymer replication via injection molding (IM). X-Ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energy and roughness data have been col...

  2. Preparation and Characterization of Copper Feedstock for Metal Injection Molding

    Directory of Open Access Journals (Sweden)

    Mohd. Afian Omar

    2010-01-01

    Full Text Available Powder loading is one of the most critical factors which have important influence on metal injection molding processes. In this study, four different loading feedstocks were prepared from gas atomized copper powder with wax-based binders. Mixes of four feedstocks with 2 Vol. % incremental powders loading from 55% to 61 Vol. % were carried out in a Z-blade mixer. The injection molding was carried out at low pressure. A combination of solvent and thermal debinding was used for binder removal from the samples and then the sintering process take place in argon gas at 900°C. It was observed that the feedstock containing 59 Vol. % of copper produce a free defect samples which was selected as the optimum feedstock.

  3. Investigation of the effect of nanoclay and processing parameters on the tensile strength and hardness of injection molded Acrylonitrile Butadiene Styrene–organoclay nanocomposites

    International Nuclear Information System (INIS)

    Highlights: • Development of polymer/clay nanocomposites. • Compatibility of ABS and montmorillonite nanoclay and composition capability of them. • Effect of nanoclay content and process parameters on the mechanical properties of nanocomposite. • Analyzing the distribution of nanoclay layers using XRD test. • Dependency of tensile strength and hardness to the nanoclay content and processing conditions. - Abstract: Polymer–clay nanocomposites have attracted considerable interest over recent years due to their dramatic improved mechanical properties. In the present study, compatibility of Acrylonitrile Butadiene Styrene (ABS) and organically modified montmorillonite nanoclay (Cloisite 30B) and composition capability of them are investigated. Polymethylmethacrylate (PMMA) in varying amount (0, 2, and 4 wt%) is used as the compatibilizer. In order to produce nanocomposite parts, the material is first compounded using a twin-screw extruder and then injected into a mold. The effect of the nanoclay percentage and processing parameters on the tensile strength and hardness of nanocomposite parts is also explored using Taguchi Design of Experiments method. Nanoclay content (in three levels: 0, 2 and 4 wt%), melt temperature (in three levels: 190, 200 and 210 °C), holding pressure (in three levels: 80, 105 and 130 MPa) and holding pressure time (in three levels: 1, 2.5 and 4 s) are considered as the variable parameters. Moreover, distribution of nanoclay layers is analyzed using Wide Angle X-ray Diffraction (XRD) test. XRD results displayed that with the presence of PMMA, nanoclay in ABS matrix is compounded in more exfoliated and less intercalated dispersion mode. Adding PMMA also leads to a remarkable increase in the fluidity of the melt during injection molding process. Results also illustrated that nanocomposites with medium loading level (i.e. 2%) of nanoclay have the highest tensile strength, while the highest hardness number belongs to nanocomposites with 4 wt% nanoclay. Obtained results also indicated that injection temperature has the most important effect on tensile strength and hardness of ABS–clay nanocomposites

  4. Injection molding tools with micro/nano-meter pattern

    DEFF Research Database (Denmark)

    Kristensen, Anders Technical University of Denmark,

    The present invention relates to methods for embedded a micrometer and/or nanometer pattern into an injection molding tool. In a first main aspect, a micro/nanometer structured imprinting device is applied in, or on, an active surface so as to transfer the micro/nanometer patterned structure to the tool while the imprinting device is, at least partly, within a cavity of the injection molding tool. In a second main aspect, a base plate with a micro/nanometer structured pattern positioned on an upper part is positioned on the active surface within the tool, the lower part of the base plate facing the tool, the active surface receiving the base plate being non-planar on a macroscopic scale. Both aspects enable a simple and effective way of transferring the pattern, and the pattern may be transferred on the active working site of tool immediately prior to molding without the need for extensive preparations or remounting of the tool before performing the molding process.

  5. Packing parameters effect on injection molding of polypropylene nanostructured surfaces

    DEFF Research Database (Denmark)

    Calaon, Matteo; Tosello, Guido

    2012-01-01

    In today´s industry, applications involving surface patterning of sub-?m to nanometer scale structures have shown a high growth potential. To investigate the injection molding capability of replicating sub-?m surface texture on a large scale area, a 30x80 mm2 tool insert with surface structures having a diameter of 500 nm was employed. The tool insert surface was produced using chemical-based-batch techniques such aluminum anodization and nickel electroplating. During the injection molding process, polypropylene (PP) was employed as material and packing phase parameters (packing time, packing pressure) were investigated. The replicated surface topographies were quantitatively characterized by atomic force microscopy using specific three-dimensional surface parameters and qualitatively inspected by scanning electron microscopy. Results showed that the degree of replication from the tool to the polymer part was mainly influenced by packing pressure level and distance from the gate.

  6. Comparison of injection molding and injection/compression molding for the replication of microstructure

    Science.gov (United States)

    Hong, Seokkwan; Hwang, Jeongho; Kang, Jeongjin; Yoon, Kyunghwan

    2015-11-01

    Because of increasing interest in the functional surfaces including micro- or nano-patterns, the mass production of such surfaces has been actively researched. Both conventional injection molding (CIM) and injection/compression molding (ICM) of micro-patterns were investigated in the present study. The molding subject is a multi-scale structure that consists of a macro-scale thin plate and micro-scale patterns formed regularly on its surface. The transcription ratios of micro pattern made by CIM and ICM for different flow length were experimentally measured, and the origin of the obtained results was identified through numerical analysis. It was found that the cavity pressure and polymer temperature are the most important factors for micro-pattern filling; in particular, the polymer temperature is the key factor determining the transcription ratio. It was also found that the difference in CIM and ICM micro-pattern transcription ratios originates from the differences in the cavity pressure history if other molding conditions are the same.

  7. Fast prototyping of injection molded polymer microfluidic chips

    International Nuclear Information System (INIS)

    We present fast prototyping of injection molding tools by the definition of microfluidic structures in a light-curable epoxy (SU-8) directly on planar nickel mold inserts. Optimized prototype mold structures could withstand injection molding of more than 300 replicas in cyclic olefin copolymer (COC) without any signs of failure or release. The key parameters to avoid mold failure are maximum adhesion strength of the epoxy to the nickel insert and minimum interfacial energy of the epoxy pattern to the molded polymer. Optimal molding of microstructures with vertical sidewalls was found for nickel inserts pre-coated by silicon oxide before applying the structured epoxy, followed by coating of the epoxy by a fluorocarbon layer prior to injection molding. Further improvements in the mold stability were observed after homogeneous coating of the patterned epoxy by a second reflowed layer of epoxy, likely due to the resulting reduction in sidewall steepness. We employed the latter method for injection molding bondable polymer microfluidic chips with integrated conducting polymer electrode arrays that permitted the culture and on-chip analysis of cell spreading by impedance spectroscopy

  8. Fast prototyping of injection molded polymer microfluidic chips

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Selmeczi, David

    2010-01-01

    We present fast prototyping of injection molding tools by the definition of microfluidic structures in a light-curable epoxy (SU-8) directly on planar nickel mold inserts. Optimized prototype mold structures could withstand injection molding of more than 300 replicas in cyclic olefin copolymer (COC) without any signs of failure or release. The key parameters to avoid mold failure are maximum adhesion strength of the epoxy to the nickel insert and minimum interfacial energy of the epoxy pattern to the molded polymer. Optimal molding of microstructures with vertical sidewalls was found for nickel inserts pre-coated by silicon oxide before applying the structured epoxy, followed by coating of the epoxy by a fluorocarbon layer prior to injection molding. Further improvements in the mold stability were observed after homogeneous coating of the patterned epoxy by a second reflowed layer of epoxy, likely due to the resulting reduction in sidewall steepness. We employed the latter method for injection molding bondable polymer microfluidic chips with integrated conducting polymer electrode arrays that permitted the culture and on-chip analysis of cell spreading by impedance spectroscopy.

  9. Modeling injection molding of net-shape active ceramic components.

    Energy Technology Data Exchange (ETDEWEB)

    Baer, Tomas (Gram Inc.); Cote, Raymond O.; Grillet, Anne Mary; Yang, Pin; Hopkins, Matthew Morgan; Noble, David R.; Notz, Patrick K.; Rao, Rekha Ranjana; Halbleib, Laura L.; Castaneda, Jaime N.; Burns, George Robert; Mondy, Lisa Ann; Brooks, Carlton, F.

    2006-11-01

    To reduce costs and hazardous wastes associated with the production of lead-based active ceramic components, an injection molding process is being investigated to replace the current machining process. Here, lead zirconate titanate (PZT) ceramic particles are suspended in a thermoplastic resin and are injected into a mold and allowed to cool. The part is then bisque fired and sintered to complete the densification process. To help design this new process we use a finite element model to describe the injection molding of the ceramic paste. Flow solutions are obtained using a coupled, finite-element based, Newton-Raphson numerical method based on the GOMA/ARIA suite of Sandia flow solvers. The evolution of the free surface is solved with an advanced level set algorithm. This approach incorporates novel methods for representing surface tension and wetting forces that affect the evolution of the free surface. Thermal, rheological, and wetting properties of the PZT paste are measured for use as input to the model. The viscosity of the PZT is highly dependent both on temperature and shear rate. One challenge in modeling the injection process is coming up with appropriate constitutive equations that capture relevant phenomenology without being too computationally complex. For this reason we model the material as a Carreau fluid and a WLF temperature dependence. Two-dimensional (2D) modeling is performed to explore the effects of the shear in isothermal conditions. Results indicate that very low viscosity regions exist near walls and that these results look similar in terms of meniscus shape and fill times to a simple Newtonian constitutive equation at the shear-thinned viscosity for the paste. These results allow us to pick a representative viscosity to use in fully three-dimensional (3D) simulation, which because of numerical complexities are restricted to using a Newtonian constitutive equation. Further 2D modeling at nonisothermal conditions shows that the choice of representative Newtonian viscosity is dependent on the amount of heating of the initially room temperature mold. An early 3D transient model shows that the initial design of the distributor is sub-optimal. However, these simulations take several months to run on 4 processors of an HP workstation using a preconditioner/solver combination of ILUT/GMRES with fill factors of 3 and PSPG stabilization. Therefore, several modifications to the distributor geometry and orientations of the vents and molds have been investigated using much faster 3D steady-state simulations. The pressure distribution for these steady-state calculations is examined for three different distributor designs to see if this can indicate which geometry has the superior design. The second modification, with a longer distributor, is shown to have flatter, more monotonic isobars perpendicular to the flow direction indicating a better filling process. The effects of the distributor modifications, as well as effects of the mold orientation, have also been examined with laboratory experiments in which the flow of a viscous Newtonian oil entering transparent molds is recorded visually. Here, the flow front is flatter and voids are reduced for the second geometry compared to the original geometry. A horizontal orientation, as opposed to the planned vertical orientation, results in fewer voids. Recently, the Navier-Stokes equations have been stabilized with the Dohrman-Bochev PSPP stabilization method, allowing us to calculate transient 3D simulations with computational times on the order of days instead of months. Validation simulations are performed and compared to the experiments. Many of the trends of the experiments are captured by the level set modeling, though quantitative agreement is lacking mainly due to the high value of the gas phase viscosity necessary for numerical stability, though physically unrealistic. More correct trends are predicted for the vertical model than the horizontal model, which is serendipitous as the actual mold is held in a vertical geometry. The full, transient mold fillin

  10. Applications of thin carbon coatings and films in injection molding

    Science.gov (United States)

    Cabrera, Eusebio Duarte

    In this research, the technical feasibility of two novel applications of thin carbon coatings is demonstrated. The first application consists of using thin carbon coatings on molds for molding ultra-thin plastic parts (parts using in mold coated nanoparticle thin films or nanopapers to create a conductive top layer. During this research, the technical feasibility of a new approach was proven which provides injection molding of ultra-thin parts at lower pressures, without the need of fast heating/fast cooling or other expensive mold modification. An in-house developed procedure by other members of our group, was employed for coating the mold surface using chemical vapor deposition (CVD) resulting in a graphene coating with carbide bonding to the mold surface. The coating resulted in a significant decrease of surface friction and consequently easiness of flow when compared to their uncoated counterparts. Thermoplastic polymers and their composites are a very attractive alternative but are hindered by the non-conductive nature of polymers. There are two general approaches used to date to achieve EMI shielding for plastic products. One is to spray a conductive metal coating onto the plastic surface forming a layer that must maintain its shielding effectiveness (SE), and its adhesion to the plastic throughout the expected life of the product. However, metal coatings add undesirable weight and tend to corrode over time. Furthermore, scratching the coating may create shielding failure; therefore, a protective topcoat may be required. The other approach is to use polymer composites filled with conductive fillers such as carbon black (CB), carbon nanofiber (CNF), and carbon nanotube (CNT). While conductive fillers may increase the electrical conductivity of polymer composites, the loading of such fillers often cannot reach a high level (parts was proven using in mold coated nanoparticle thin films or nanopapers to create a conductive top layer. For many years, in-mold coating (IMC) has been commercially applied to Sheet Molding Compound (SMC) compression molded parts, as an environmentally friendly approach to improve its surface quality and provide the required conductivity for electrostatic painting using carbon black (CB). Such process can also be applied to injection molding for creating a top conductive layer. Increasing the amount of CB will increase the surface conductivity of the coated part, thus improving the paint transfer efficiency. However the CB levels needed to achieve the conductivity levels required for achieving EMI shielding would make the coating viscosity too large for proper coating. Nanopaper based composites are excellent candidates for EMI shielding because of the nanopaper's high concentration of carbon nanofibers (CNFs) (~2 wt% to 10 wt% depending on nanopaper/thermoplastic thickness and 71wt.% to 79wt.% in the nanopaper itself after resin infusion) and high conductivity of the nanopaper. Instead of premixing nanoparticles with IMC coating, nanopapers enable the use of low viscosity IMC without CB coating to impregnate the CNF network in order to reach high electrical conductivity and EMI shielding values. (Abstract shortened by UMI.).

  11. Binder Removal from Powder Injection Molded 316L Stainless Steel

    Directory of Open Access Journals (Sweden)

    M.A. Omar

    2011-01-01

    Full Text Available This study reports the results of preparation of 316L stainless steel polymer based injection molded feed stock, rheology of feed stock and injection molding. The plastic binder was extracted from molded samples. The binder extraction was carried out in two steps: by solvent and thermal techniques. The results showed that feed stock prepared was suitable for injection molding and this was confirmed by rheology data measured by using capillary rheometer. The test samples were injection molded without physical defects. Paraffin Wax (major binder was extracted by using solvent extraction for 300 min. The thermal debinding was performed four different heating rates rage 1-7C min-1. The SEM results showed that the PW was completely extracted from the test samples after 300 min.

  12. Comparative Thermal Analysis of Circular and Profiled Cooling Channels for Injection Mold Tools

    Directory of Open Access Journals (Sweden)

    A.M.A. Rani

    2011-01-01

    Full Text Available Injection Mold Thermal Management is a critical issue in plastic injection molding process and has major effects on production cycle times that is directly linked with cost and also has effects on part quality. For this reason, cooling system design has great significance for plastic products industry by injection molding. It is crucial not only to reduce molding cycle time but also it considerably affects the productivity and quality of the product. The cooling channels in injection molding have circular cross section due to the conventional manufacturing technique of drilling. In Rapid Prototyping and Tooling techniques of fabricating conformal cooling channels, the channel cross section is again circular. In circular channel, there can be a problem that the distance from the edges of channel to the cavity is not constant and it is variable even for conformal channels. This can give problem of not having even heat dissipation. In this study, injection mold designing and thermal simulations were performed and comparison is presented between molds having cooling channels of circular cross section with mold with profiled cross section channels. Thermal analysis and simulations can effectively predict the performance of circular channels as compared to profiled channels. Some concepts are also presented for the manufacturing of molds with circular and profiled channels with the use of metal filled epoxies.

  13. Effects of mold geometry on fiber orientation of powder injection molded metal matrix composites

    Science.gov (United States)

    Ahmad, Faiz; Aslam, Muhammad; Altaf, Khurram; Shirazi, Irfan

    2015-07-01

    Fiber orientations in metal matrix composites have significant effect on improving tensile properties. Control of fiber orientations in metal injection molded metal composites is a difficult task. In this study, two mold cavities of dimensions 6x6x90 mm and 10x20x180 mm were used for comparison of fiber orientation in injection molded metal composites test parts. In both mold cavities, convergent and divergent flows were developed by modifying the sprue dimensions. Scanning electron microscope (SEM) was used to examine the fiber orientations within the test samples. The results showed highly aligned fiber in injection molded test bars developed from the convergent melt flow. Random orientation of fibers was noted in the composites test bars produced from divergent melt flow.

  14. The use of stereolithography rapid tools in the manufacturing of metal powder injection molding parts

    Scientific Electronic Library Online (English)

    V. E., Beal; C. H., Ahrens; P. A., Wendhausen.

    2004-03-01

    Full Text Available The utilization of stereolithography molds in the manufacture pre-series for injection molded plastic parts aims to reduce costs throughout the product life-time, but mainly during design and manufacturing phases. The use of this Rapid Tooling technique in powder metal injection molding is evaluated [...] in this work. One of the greatest differences between traditional and stereolithography tools is related to the heat conductivity of the materials employed. For example, steel molds have a heat conductivity coefficient 300 times higher than molds made with the photosensitive resin used in the stereolithography process. The discrepancy regarding the cooling rate of the molded parts during the injection cycle must be compensated with adjustments in the injection molding parameters, such as temperature, pressure and speed. The optimization of these parameters made it possible to eject green parts from the mold without causing defects which would become evident in debinding and sintering stages. The dimensional analysis performed at the end of each case study showed that the shrinking factor of the component after the sintering had the same value obtained for components using traditional metallic molds. Moreover, the dimensional error remains under 2% which can be considered low for a pre-series of components (or prototype series).

  15. Analysis of Cavity Pressure and Warpage of Polyoxymethylene Thin Walled Injection Molded Parts: Experiments and Simulations

    DEFF Research Database (Denmark)

    Guerrier, Patrick; Tosello, Guido

    2014-01-01

    Process analysis and simulations on molding experiments of 3D thin shell parts have been conducted. Moldings were carried out with polyoxymethylene (POM). The moldings were performed with cavity pressure sensors in order to compare experimental process results with simulations. The warpage was characterized by measuring distances using a tactile coordinate measuring machine (CMM). Molding simulations have been executed taking into account actual processing conditions. Various aspects have been considered in the simulation: machine barrel geometry, injection speed profiles, cavity injection pressure, melt and mold temperatures, material rheological and pvT characterization. Factors investigated for comparisons were: injection pressure profile, short shots length, flow pattern, and warpage. A reliable molding experimental database was obtained, accurate simulations were conducted and a number of conclusions concerning improvements to simulation accuracy are presented regarding: pvT data, mesh, short shots, cavity pressure for process control validation as well as molding machine geometry modelling. Eventually, a methodology for improved molding simulations of cavity injection pressure, filling pattern and warpage was established.

  16. An X-ray Scattering Study of Water-Conditioned Injection- Molded Starch during Isothermal Heating

    OpenAIRE

    Cagiao, M.E.; Bayer, R. K.; Rueda, D. R.; Baltá Calleja, F. J.

    2003-01-01

    The in situ structure variation of injection molded starch (as processed and after water conditioning)during heat treatment was investigated by means of wideangle X-ray scattering using synchrotron radiation. Results confirm that the crystal structure of potato starch is destroyed after injection molding, while as-processed corn starch preserves some degree of crystallinity. This residual crystallinity in corn starch is related to the crystalline Vh form,made of complexes of amylose with l...

  17. Replication of diffractive optical elements by injection molding

    Science.gov (United States)

    Carvalho, E. J.; Braga, Edmundo S.; Cescato, Lucila H. D.

    2004-10-01

    In this paper we describe the replication processes of DOE carried out at the Diffractive Optics Laboratory/UNICAMP for replicating DOE. In particular we present the results obtained in the replication by injection molding of microlens array, diffraction gratings and polarizing elements. The measurements of the geometric dimensions of the DOE masters, the nickel shims and the replicated structures were accomplished by perfilometry, AFM and SEM microscopy. The optical properties of both the DOE masters and their replicas were evaluated by measuring of the diffraction efficiency as a function of the incident wavelength, for orthogonal polarizations.

  18. Transparent thermoplastics: Replication of diffractive optical elements using micro-injection molding

    Science.gov (United States)

    Kalima, V.; Pietarinen, J.; Siitonen, S.; Immonen, J.; Suvanto, M.; Kuittinen, M.; Mönkkönen, K.; Pakkanen, T. T.

    2007-10-01

    Small plastic components with sub-micron and micron gratings for diffractive optics were prepared by micro-injection molding. The aim of the work was to improve the filling of binary diffractive gratings with high aspect ratio by varying the molding parameters. Tests were made under conventional processing conditions with four transparent thermoplastics: polycarbonate (PC), cyclo-olefin polymer (COP), styrene-acrylonitrile copolymer (SAN), and hexafluoropropylene-tetrafluoroethylene-ethylene terpolymer (HFP-TFE-Et). Melt and mold temperatures were kept as recommended by the manufacturer. Other molding parameters (injection speed, shot size, vacuum, holding pressure, and injection plunger diameter) were varied, and their effect on the profile of the gratings was measured by atomic force microscopy. The filling of the gratings (500 nm and 1000 nm) was clearly affected by injection speed, shot size, and injection piston diameter, but the most significant factor was the type of material. Replication fidelity was highest with PC and lowest with SAN.

  19. Aplicação das técnicas de planejamento e análise de experimentos no processo de injeção plástica Application design of experiments in the injection molding process

    Directory of Open Access Journals (Sweden)

    Edwin V. Cardoza Galdamez

    2004-04-01

    Full Text Available Experimentos industriais são realizados pelas empresas com o intuito de melhorar o desempenho dos produtos e os processos de fabricação. Nesse sentido, este trabalho tem por objetivo estudar e aplicar as técnicas de planejamento e análise de experimentos na melhoria da qualidade industrial. Especificamente são aplicadas as técnicas de planejamento Fatorial Fracionado 2k-p, Metodologia de Superfície de Resposta e Análise de Variância, em um processo de moldagem por injeção plástica. Com essa pesquisa experimental foi possível identificar os níveis ótimos de regulagem e os parâmetros mais importantes da injeção plástica: temperatura da máquina e pressão de injeção. Para finalizar é avaliado o procedimento de implementação das técnicas de experimentação e as dificuldades práticas encontradas na empresa.Industrial experiments are made by companies in order to improve the quality characteristics of products and production processes. In this sense, the objective of this paper is to study and apply the design of experiments in the industrial quality improvement. In addition, as a part of the objective, an application of the techniques of design Fractional Factorial 2k-p, Analysis of Variance and Response Surface Methodology is done. It is focused in an injection molding process applied by a company, that makes and trades plastic products for the civil construction. Using this experimental study, the most important parameters of plastic injection are identified: machine temperature and injection pressure. At the same time, the optimal levels of adjustment of these parameters are determined. From this study, it is evaluated both the implantation procedures of the designs of experiments as well as the difficulties faced. Also, this study tries to contribute to the university-company relationship.

  20. Aplicação das técnicas de planejamento e análise de experimentos no processo de injeção plástica / Application design of experiments in the injection molding process

    Scientific Electronic Library Online (English)

    Edwin V. Cardoza, Galdamez; Luiz C. Ribeiro, Carpinetti.

    2004-04-01

    Full Text Available Experimentos industriais são realizados pelas empresas com o intuito de melhorar o desempenho dos produtos e os processos de fabricação. Nesse sentido, este trabalho tem por objetivo estudar e aplicar as técnicas de planejamento e análise de experimentos na melhoria da qualidade industrial. Especifi [...] camente são aplicadas as técnicas de planejamento Fatorial Fracionado 2k-p, Metodologia de Superfície de Resposta e Análise de Variância, em um processo de moldagem por injeção plástica. Com essa pesquisa experimental foi possível identificar os níveis ótimos de regulagem e os parâmetros mais importantes da injeção plástica: temperatura da máquina e pressão de injeção. Para finalizar é avaliado o procedimento de implementação das técnicas de experimentação e as dificuldades práticas encontradas na empresa. Abstract in english Industrial experiments are made by companies in order to improve the quality characteristics of products and production processes. In this sense, the objective of this paper is to study and apply the design of experiments in the industrial quality improvement. In addition, as a part of the objective [...] , an application of the techniques of design Fractional Factorial 2k-p, Analysis of Variance and Response Surface Methodology is done. It is focused in an injection molding process applied by a company, that makes and trades plastic products for the civil construction. Using this experimental study, the most important parameters of plastic injection are identified: machine temperature and injection pressure. At the same time, the optimal levels of adjustment of these parameters are determined. From this study, it is evaluated both the implantation procedures of the designs of experiments as well as the difficulties faced. Also, this study tries to contribute to the university-company relationship.

  1. Computer Aided Design of The Cooling System for Plastic Injection Molds

    Directory of Open Access Journals (Sweden)

    Hakan GÜRÜN

    2009-02-01

    Full Text Available The design of plastic injection molds and their cooling systems affect both the dimension, the shape, the quality of a plastic part and the cycle time of process and the cost of mold. In this study, the solid model design of a plastic injection mold and the design of cooling sysytem were possibly carried out without the designer interaction. Developed program permited the use of three types of the cooling system and the different cavity orientations and the multible plastic part placement into the mold cores. The program which was developed by using Visual LISP language and the VBA (Visual BASIC for Application modules, was applicated in the AutoCAD software domain. Trial studies were presented that the solid model design of plastic injection molds and the cooling systems increased the reliability, the flexibility and the speed of the design.

  2. A Review of Effects of Molding Methods, Mold Thickness and Other Processing Parameters on Fiber Orientation in Polymer Composites

    Directory of Open Access Journals (Sweden)

    Ahmed N. Oumer

    2013-01-01

    Full Text Available In injection molded fiber reinforced composites, the mechanical and physical properties of the final product are highly dependent on the patterns of fibers alignment. The orientation of the fibers can be influenced by many factors such as molding methods, materials used, geometry of the part and other processing parameters. Thus, there is considerable interest in studying the factors that affect the fiber orientation, hence the properties of the final product. This study presented a general review on the effects of these factors on fiber orientation in injection molded fiber-reinforced polymer composites. The fiber orientation of a part made by conventional injection molding is compared with those produced by injection-compression and push-pull injection techniques. Effects of injection speed, type of flow and mold thickness on fiber orientation are also discussed. Hence, this review could assist in decisions regarding the design of composite products.

  3. Residual stress distribution in injection molded parts

    OpenAIRE

    P. Postawa; Kwiatkowski, D.

    2006-01-01

    Purpose: The paper presents the results of the investigations of influence of the amorphous polystyrene (PS)processing on the diversity of the internal stresses observed in the injection moulded piece.Design/methodology/approach: For the tests, the standardized mould piece designed for the investigations ofthe processing shrinkage of thermoplastics materials has been used. The samples have been prepared using theDesign of Experiment (DoE) theory.The state of internal stresses has been analyse...

  4. Residual orientation in micro-injection molded parts

    International Nuclear Information System (INIS)

    The residual orientation following micro-injection molding of small rectangular plates with linear polyethylene has been examined using small-angle neutron scattering, and small- and wide-angle X-ray scattering. The effect of changing the molding conditions has been examined, and the residual chain orientation has been compared to the residual orientation of the crystallites as a function of position in the sample. This study has found that, for micromoldings, the orientation of the crystallites decreases with increasing injection speed and increasing mold thickness. The combined data suggest that the majority of the orientation present comes from oriented crystal growth rather than residual chain orientation.

  5. A Recurrent Neural Network for Warpage Prediction in Injection Molding

    Scientific Electronic Library Online (English)

    A., Alvarado-Iniesta; D.J., Valles-Rosales; J.L., García-Alcaraz; A., Maldonado-Macias.

    2012-12-01

    Full Text Available La inyección de plásticos se considera como uno de los procesos de manufactura más flexibles y económicos con un gran volumen de producción de piezas de plástico. Las causas de variación durante la inyección de plásticos se relacionan con el amplio número de factores que intervienen durante un ciclo [...] de producción regular, tales variaciones impactan la calidad del producto final. Un problema común de calidad en productos terminados es la presencia de deformaciones. Así, este estudio tuvo como objetivo diseñar un sistema basado en redes neuronales recurrentes para predecir defectos de deformación en productos fabricados por medio de inyección de plásticos. Se emplean cinco parámetros del proceso por ser considerados críticos y que tienen un gran impacto en la deformación de componentes plásticos. El presente estudio hizo uso del software de análisis finito llamado Moldflow para simular el proceso de inyección de plásticos para recolectar datos con el fin de entrenar y probar la red neuronal recurrente. Redes neuronales recurrentes fueron utilizadas para entender la dinámica del proceso y debido a su capacidad de memorización, los valores de deformación pudieron ser predichos con exactitud. Los resultados muestran que la red diseñada funciona bien en términos de predicción, superando aquellas predicciones generadas por redes de propagación hacia adelante. Abstract in english Injection molding is classified as one of the most flexible and economical manufacturing processes with high volume of plastic molded parts. Causes of variations in the process are related to the vast number of factors acting during a regular production run, which directly impacts the quality of fin [...] al products. A common quality trouble in finished products is the presence of warpage. Thus, this study aimed to design a system based on recurrent neural networks to predict warpage defects in products manufactured through injection molding. Five process parameters are employed for being considered to be critical and have a great impact on the warpage of plastic components. This study used the finite element analysis software Moldflow to simulate the injection molding process to collect data in order to train and test the recurrent neural network. Recurrent neural networks were used to understand the dynamics of the process and due to their memorization ability, warpage values might be predicted accurately. Results show the designed network works well in prediction tasks, overcoming those predictions generated by feedforward neural networks.

  6. Injection molded dielectromagnets prepared from mixture of hard magnetic powders

    International Nuclear Information System (INIS)

    Dielectromagnets are permanent magnets prepared from a hard magnetic powder bonded by binder. These permanent magnets are termed also as bonded permanent magnets. There are two ways to prepare dielectromagnets: compression molding and injection molding. Dielectromagnets prepared by injection molding, from the same hard magnetic powders, have worse magnetic properties than dielectromagnets prepared by compression molding, but they are cheaper. Isotropic dielectromagnets prepared from ferrite powder have low value of magnetic properties, but their advantage is positive value of temperature coefficient of JHc. They are low in price. Dielectromagnets prepared from melt-spun Nd-Fe-B have high values of magnetic properties.Value of temperature coefficient of JHc is their weakness. They are more expensive than ferrite dielectromagnets. Comparison of advantages and disadvantages of dielectromagnets prepared from different kinds of hard magnetic powder has produced an idea of making dielectromagnets from the mixture of these powders prepared by compression molding have magnetic and thermal properties of values between values of dielectromagnets from Nd-Fe-B and ferrite powders. It was described elsewhere. The purpose of this investigation is to prepare injection molded dielectromagnets from mixture of powders of strontium ferrite and melt-spun ribbon Nd-Fe-B and to find correlation between the composition of the mixture and magnetic properties of dielectromagnets. A result of mixture composition on magnetic properties of injection molded dielectromagnets is shown. (author)

  7. Powder Injection Molding of Al-(Steel and Magnet) Hybrid Components

    Science.gov (United States)

    Liu, Z. Y.; Kent, D.; Schaffer, G. B.

    2009-12-01

    A powder injection molding (PIM) process was developed to prepare aluminum hybrid components incorporating low carbon steel, AlNiCo, or BaFeO magnetic inserts. The inserts were securely bound within the powder injection molded aluminum due to sintering shrinkage and physical reaction at the interface. The low sintering temperature of the aluminum alloy ensured a minimal level of interfacial reaction and limited the degradation of the properties of the inserts.

  8. Injection-Molded Soft Magnets Prepared from Fe-Based Metallic Glass: Mechanical and Magnetic Properties

    Science.gov (United States)

    Zhong, Tian; Huang, Ran; Huang, Jia; Ouyang, Wei

    2015-09-01

    The injection-molded metallic glass soft magnet is prepared from the powder of melt-spun ribbon of Fe36Co36B20Si4Nb4 glassy alloy and Nylon 6,6 of wt.% from 5 to 20 via the polymer injection molding technology. The product is characterized by the SEM, mechanical, and magnetic test. The results indicate that this type of materials has comparable mechanical properties and morphological feature with the conventional injection-molded NdFeB magnet and exhibits excellent soft magnetic behaviors. The magnetic properties of the injected magnets are compared with the raw metallic glass, solvent-casted resin bonding magnets, and thermal-treated magnets to confirm that the processing temperature of Nylon injection does not affect the magnetism. The injection technology is a practical processing method to be applied on the metallic glass for potential usage.

  9. Injection-Molded Soft Magnets Prepared from Fe-Based Metallic Glass: Mechanical and Magnetic Properties

    Science.gov (United States)

    Zhong, Tian; Huang, Ran; Huang, Jia; Ouyang, Wei

    2015-10-01

    The injection-molded metallic glass soft magnet is prepared from the powder of melt-spun ribbon of Fe36Co36B20Si4Nb4 glassy alloy and Nylon 6,6 of wt.% from 5 to 20 via the polymer injection molding technology. The product is characterized by the SEM, mechanical, and magnetic test. The results indicate that this type of materials has comparable mechanical properties and morphological feature with the conventional injection-molded NdFeB magnet and exhibits excellent soft magnetic behaviors. The magnetic properties of the injected magnets are compared with the raw metallic glass, solvent-casted resin bonding magnets, and thermal-treated magnets to confirm that the processing temperature of Nylon injection does not affect the magnetism. The injection technology is a practical processing method to be applied on the metallic glass for potential usage.

  10. Design of Multimodel based MPC and IMC control schemes applied to injection molding machine

    Directory of Open Access Journals (Sweden)

    Kanaga Lakshmi

    2014-03-01

    Full Text Available Good control of plastic melt temperature for injection molding is very important in reducing operator setup time, ensuring product quality, and preventing thermal degradation of the melt. The controllability and set points of barrel temperature also depend on the precise monitoring and control of plastic melt temperature. Motivated by the practical temperature control of injection molding, this paper proposes MPC and IMC based control scheme. A robust system identification and control methodology is developed which uses canonical varieties analysis for identification and model predictive control for regulation. The injection molding process consists of three zones and the mathematical model for each of the zone is different. The control output for each zone controller is assigned a weight based on the computed probability of each model and the resulting action is the weighted average of the control moves of the individual zone controllers.   Keywords: Injection-Molding Machine (IMM, IMC Control, Temperature Control.

  11. Fabrication of microstructures with extreme structural heights by vacuum reaction injection molding and electroforming

    International Nuclear Information System (INIS)

    Development work has resulted in a vacuum reaction injection molding (RIM) process which allows to fabricate plastic microstructures having minimum lateral dimensions in the micrometer range and structural heights of several hundred micrometers. The plastic structures generated by this method on an electrically conductive gate plate can be used directly as templates for the production of metallic microstructures through electroforming. The mold inserts for the molding tools used in the RIM process are fabricated by synchrotron radiation lithography and electroforming on an electrically conductive base plate. Particularly stable mold inserts made of one single material with extremely plane surfaces are obtained by electrodeposition of metal such that it stands by several millimeters over the resist structures generated by lithography. The mold insert produced in this way is separated from the base plate and the resist structures are subsequently removed. The molding tests were performed at a purpose developed vacuum RIM apparatus. Methacrylate base casting resins were used with an internal mold release agent added in order to reduce the adhesion of the produced part on the mold insert. By the example of fabrication of separation nozzle structures with minimum lateral dimensions of about 3 ?m and a maximum structural height of 310 ?m it has been demonstrated that molding can be performed at 100% yield and that service lives of the mold inserts can be achieved which are adequate for mass production. (orig./HP)

  12. Experimental Analysis for Factors Affecting the Repeatability of Plastics Injection Molding Tests on the Self-developed Apparatus

    OpenAIRE

    Yuejun Liu; Yugang Huang; Duxin Li

    2013-01-01

    To improve the repeatability of the injection molding test result, the affecting factors were investigated by means of experiments. Besides the traditional processing parameter, the factors of test conditions were also considered. In order to focus on the molding process rather than the molded part, the curve measurement of the melt pressure at the entrance to the nozzle was used as the output characteristic. Experiments for polypropylene (PP) showed that the injected volume was the key proc...

  13. Evaluation of stability for monolayer injection molding tools coating

    DEFF Research Database (Denmark)

    Cech, Jiri; Taboryski, Rafael J.

    2012-01-01

    We tested and characterized molecular coating of Aluminium and Nickel prototype molds and mold inserts for polymer replication via injection molding (IM). X-Ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energy and roughness data have been collected and used to predict coating lifetimes. Samples have been characterized immediately after coating, after 500+ IM cycles to test durability and after 7 months to test temporal stability. Sessile drop contact angle was measured for multiple fluids, namely water, di-iodomethane and benzylacohol. Detectable coating presence was indicated by an increased angle on all post IM samples. To conclude, we present mold coating evaluation method, which is well suited for ultrathin, controlable, covalently bonded coating, that is reasonably durable, affordable, scalable to production, detectable on surface and especially suitable for rapid prototyping and mold geometry testing.

  14. POWDER INJECTION MOLDING OF SIC FOR THERMAL MANAGEMENT V

    Directory of Open Access Journals (Sweden)

    Valmikanathan Onbattuvelli

    2012-06-01

    Full Text Available Silicon carbide (SiC exhibits many functional properties that are relevant to applications in electronics, aerospace, defense and automotive industries. However, the successful translation of these properties into final applications lies in the net-shaping of ceramics into fully dense microstructures. Increasing the packing density of the starting powders is one effective route to achieve high sintered density and dimensional precision. The present paper presents an in-depth study on the effects of nanoparticle addition on the powder injection molding process (PIM of SiC powder-polymer mixtures. In particular, bimodal mixtures of nanoscale and sub-micrometer particles are found to have significantly increased powder packing characteristics (solids loading in the powder-polymer mixtures. The influence of nanoparticle addition on the multi-step PIM process is examined. The above results provide new perspectives which could impact a wide range of materials, powder processing techniques and applications.

  15. A comparative study of Ni-Ti and Ni-Ti-Cu shape memory alloy processed by plasma melting and injection molding

    International Nuclear Information System (INIS)

    Highlights: ? There is only one paper in the literature that uses the PSPP process to fabricate shape memory alloys (SMA). ? Two specific mechanical assemblies have been developed to measure force generated by SMA small strips. ? A relationship between hardness and force generated by the studied Ni-Ti SMA was first established. ? A more focused and specific comparison was still necessary to clarify the effect of copper in Ni-Ti. -- Abstract: Shape memory alloys (SMA) are smart materials that present potential applications in such diverse areas as aeronautics, automotive, electronics, biomedicine and others. This work aimed at comparing some physical and functional properties of a Ni-Ti-Cu and equiatomic Ni-Ti SMA. Therefore, Ni-50Ti and Ni-50Ti-5Cu (at.%) were manufactured using plasma melting followed by injection in metallic mold, named Plasma Skull Push-Pull (PSPP) process. Afterwards, samples of both Ni-Ti based SMA were annealed at 1113 K during 2400 s and water quenched. The obtained specimens were analyzed by optical microscopy, microhardness, differential scanning calorimetry, electrical resistance as a function of temperature, and force generation tests. The results showed that Ni-Ti alloy presented higher levels of hardness and lower generated recover forces during heating when compared to the Ni-Ti-Cu SMA. Moreover, the Ni-Ti alloy holds hysteresis larger than the Ni-Ti-Cu SMA as a result of the presence of the R-phase transformation. There was also a better stability under thermal cycling of NiTiCu SMA compared with the equiatomic NiTi.

  16. Fatigue failure properties of injection molded superalloy compacts

    International Nuclear Information System (INIS)

    Superalloys have been used especially for aerospace and atomic energy applications because of their excellent attributes of high corrosion and oxidation resistance, and high temperature strength. A Inconel 718 is one of representative Ni-base superalloys. However, it is not easy to produce the complicate shaped parts with low cost due to their poor workability. In this study, Metal Injection Molding (MIN) process, one of near net-shape powder forming, has been applied to fabricate the Inconel 718 alloy compacts using type of powder; gas and water atomized powders. By optimizing the MIM process, their obtained relative density was near full density (98 - 99%). However, the fatigue strength of heat treated sintered Inconel 718 compacts showed 65% of heat treated wrought materials due to the remained pores. The effect of remained pores on fatigue strength was discussed by the prediction equation of endurance limit considering the inclusion. (author)

  17. Caracterización del aluminio para la fabricación de insertos de moldes de inyección de plásticos. // Aluminium alloys behaviour used in the manufacturing of cavities in molds for plastic injection process.

    Directory of Open Access Journals (Sweden)

    H. González Zulueta

    2008-09-01

    Full Text Available Se describe una investigación experimental realizada para estudiar el comportamiento en condiciones reales de insertospara cavidades fabricados con dos aleaciones de aluminio diferentes. Se fabricaron 1000 piezas (probetas para ensayo deplásticos de polipropileno, empleando un molde de diseño normalizado con insertos para la cavidad correspondiente,fabricados con cada una de las aleaciones a ensayar. Cada 250 piezas producidas, tanto las cavidades como la piezaelaborada fueron medidas en zonas previamente seleccionadas y estos resultados se emplearon para caracterizar elcomportamiento de las aleaciones ensayadas. Las condiciones de presión y temperatura del proceso de inyección seseleccionaron atendiendo a los requerimientos industriales que corresponden al plástico utilizado.Palabras claves: Moldes, cavidades, aluminio, experimento, inyección de plástico.__________________________________________________________________________Abstract:The behaviour of cavities in molds for plastic injection, manufactured with two different aluminium alloys under realconditions is described by experimental investigation. 1000 pieces (probes for testing mechanical properties of plastics wereproduced from polypropylene, using a normalized designed mold with specially manufactured cavities and the two testedalloys. For the produced pieces, the dimension (width of the cavities and the elaborated pieces were measured in previouslyselected areas, these results were used to characterize the behaviour of the tested alloys. The conditions of pressure andtemperature for the injection process were selected according to the industrial requirements for the plastic used in theinvestigation.Key words: Mold, cavity, aluminium, experiment.

  18. Three dimensional modeling of metal powder injection molding

    International Nuclear Information System (INIS)

    In this work, a three-dimensional transient finite element flow analysis code is used to solve powder injection molding problems. Free surface, non-isothermal flow solutions are obtained by solving the momentum, mass and energy equations. An additional transport equation is solved for the front tracking function indicating the flow front position. The flow of 17-4 stainless steel powder with a water-soluble binder is simulated in a thick three-dimensional part with a diaphragm gate. The compound used is very sensitive to thermal effects because of its high thermal diffusivity and highly sensitive temperature dependence of the viscosity. The simulation predicted several unusual experimentally observed flow patterns: bypass flow (flow external and/or internal to the initial annular flow) and nonuniform flow (nonaxisymmetric flow in a preferred direction through the diaphragm gate). The work considers the effect of filling time, melt/mold temperature, inertia, yield stress, and wall slip on flow patterns, in order to identify the processing conditions that separate regions of uniform and nonuniform flow. (author)

  19. A Simulation Study of Conformal Cooling Channels in Plastic Injection Molding

    OpenAIRE

    Omar A. Mohamed, S.H. Masood, Abul Saifullah

    2013-01-01

    In injection molding process, the cooling channel performance is one of the most crucial factors because it has significant effect on both production rate and the quality of the plastic part. In order to reduce the cycle time, and control the uniform distribution of temperature, it is necessary to create conformal cooling channels, which conform to the shape of the mold cavity and core. This paper presents a simulation study of different types of cooling channe...

  20. Electrical and dielectric properties of foam injection-molded polypropylene/multiwalled carbon nanotube composites

    Energy Technology Data Exchange (ETDEWEB)

    Ameli, A.; Nofar, M.; Saniei, M.; Hossieny, N.; Park, C. B. [Microcellular Plastics Manufacturing Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, 5 King’s College Road, Toronto, Ontario, Canada M5S 3G8 (Canada); Pötschke, P. [Leibniz-Institut für Polymerforschung Dresden e.V. (IPF), Hohe Strasse 6, D-01069 Dresden (Germany)

    2015-05-22

    A combination of high dielectric permittivity (ε′) and low dielectric loss (tan δ) is required for charge storage applications. In percolative systems such as conductive polymer composites, however, obtaining high ε′ and low tan δ is very challenging due to the sharp insulation-conduction transition near the threshold region. Due to the particular arrangement of conductive fillers induced by both foaming and injection molding processes, they may address this issue. Therefore, this work evaluates the application of foam injection molding process in fabricating polymer nanocomposites for energy storage. Polypropylene-multiwalled carbon nanotubes (PP-MWCNT) composites were prepared by melt mixing and foamed in an injection molding process. Electrical conductivity (σ), ε′ and tan δ were then characterized. Also, scanning and transmission electron microscopy (SEM and TEM) was used to investigate the carbon nanotube’s arrangement as well as cellular morphology. The results showed that foam injection-molded composites exhibited highly superior dielectric properties to those of solid counterparts. For instance, foamed samples had ε′=68.3 and tan δ =0.05 (at 1.25 vol.% MWCNT), as opposed to ε′=17.8 and tan δ=0.04 in solid samples (at 2.56 vol.% MWCNT). The results of this work reveal that high performance dielectric nanocomposites can be developed using foam injection molding technologies for charge storage applications.

  1. Electrical and dielectric properties of foam injection-molded polypropylene/multiwalled carbon nanotube composites

    Science.gov (United States)

    Ameli, A.; Nofar, M.; Saniei, M.; Hossieny, N.; Park, C. B.; Pötschke, P.

    2015-05-01

    A combination of high dielectric permittivity (?') and low dielectric loss (tan ?) is required for charge storage applications. In percolative systems such as conductive polymer composites, however, obtaining high ?' and low tan ? is very challenging due to the sharp insulation-conduction transition near the threshold region. Due to the particular arrangement of conductive fillers induced by both foaming and injection molding processes, they may address this issue. Therefore, this work evaluates the application of foam injection molding process in fabricating polymer nanocomposites for energy storage. Polypropylene-multiwalled carbon nanotubes (PP-MWCNT) composites were prepared by melt mixing and foamed in an injection molding process. Electrical conductivity (?), ?' and tan ? were then characterized. Also, scanning and transmission electron microscopy (SEM and TEM) was used to investigate the carbon nanotube's arrangement as well as cellular morphology. The results showed that foam injection-molded composites exhibited highly superior dielectric properties to those of solid counterparts. For instance, foamed samples had ?'=68.3 and tan ? =0.05 (at 1.25 vol.% MWCNT), as opposed to ?'=17.8 and tan ?=0.04 in solid samples (at 2.56 vol.% MWCNT). The results of this work reveal that high performance dielectric nanocomposites can be developed using foam injection molding technologies for charge storage applications.

  2. Electrical and dielectric properties of foam injection-molded polypropylene/multiwalled carbon nanotube composites

    International Nuclear Information System (INIS)

    A combination of high dielectric permittivity (??) and low dielectric loss (tan ?) is required for charge storage applications. In percolative systems such as conductive polymer composites, however, obtaining high ?? and low tan ? is very challenging due to the sharp insulation-conduction transition near the threshold region. Due to the particular arrangement of conductive fillers induced by both foaming and injection molding processes, they may address this issue. Therefore, this work evaluates the application of foam injection molding process in fabricating polymer nanocomposites for energy storage. Polypropylene-multiwalled carbon nanotubes (PP-MWCNT) composites were prepared by melt mixing and foamed in an injection molding process. Electrical conductivity (?), ?? and tan ? were then characterized. Also, scanning and transmission electron microscopy (SEM and TEM) was used to investigate the carbon nanotube’s arrangement as well as cellular morphology. The results showed that foam injection-molded composites exhibited highly superior dielectric properties to those of solid counterparts. For instance, foamed samples had ??=68.3 and tan ? =0.05 (at 1.25 vol.% MWCNT), as opposed to ??=17.8 and tan ?=0.04 in solid samples (at 2.56 vol.% MWCNT). The results of this work reveal that high performance dielectric nanocomposites can be developed using foam injection molding technologies for charge storage applications

  3. The Shrinkage Behavior and Surface Topographical Investigation for Micro Metal Injection Molding

    DEFF Research Database (Denmark)

    Islam, Aminul; Giannekas, Nikolaos

    2014-01-01

    Metal injection molding (MIM) is a near net shape manufacturing technology that can produce highly complex and dimensionally stable parts for high end engineering applications. Despite the recent growth and industrial interest, micro metal molding is yet to be the field of extensive research especially when it is compared with micro molding of thermoplastics. The current paper presents a thorough investigation on the process of metal injection molding where it systematically characterizes the effects of important process conditions on the shrinkage and surface quality of molded parts with micro features. Effects of geometrical factors like feature dimensions and distance from the gate on the replication quality are studied. The influence of process conditions on the achievable roughness for the final metal parts is discussed based on the experimental findings. The test geometry is characterized by 2½D surface structures containing thin ribs of different aspect ratios and thicknesses in the sub-mm dimensional range. The test parts were molded from Catamold 316L with a conventional injection molding machine. Afterwards, the parts were de-binded and sintered to produce the final test samples. Among the different process parameters studied, the melt temperature was the most influential parameters for better replication and dimensional stability of the final part. The results presented in the paper clearly show that the shrinkage in metal part is not uniform in the micro scale. It depends on the feature dimensions and also on the process conditions. A thin section of the part exhibits higher relative shrinkage compared with a thicker section. Based on these findings, it can be concluded that a micro part molded by MIM process will have higher relative shrinkage compared to a macro part made with the same process.

  4. The shrinkage behavior and surface topographical investigation for micro metal injection molding

    Science.gov (United States)

    Islam, A.; Giannekas, N.; Marhöfer, D. M.; Tosello, G.; Hansen, H. N.

    2015-05-01

    Metal injection molding (MIM) is a near net shape manufacturing technology that can produce highly complex and dimensionally stable parts for high end engineering applications. Despite the recent growth and industrial interest, micro metal molding is yet to be the field of extensive research especially when it is compared with micro molding of thermoplastics. The current paper presents a thorough investigation on the process of metal injection molding where it systematically characterizes the effects of important process conditions on the shrinkage and surface quality of molded parts with micro features. Effects of geometrical factors like feature dimensions and distance from the gate on the replication quality are studied. The influence of process conditions on the achievable roughness for the final metal parts is discussed based on the experimental findings. The test geometry is characterized by 2½D surface structures containing thin ribs of different aspect ratios and thicknesses in the sub-mm dimensional range. The test parts were molded from Catamold 316L with a conventional injection molding machine. Afterwards, the parts were de-binded and sintered to produce the final test samples. Among the different process parameters studied, the melt temperature was the most influential parameters for better replication and dimensional stability of the final part. The results presented in the paper clearly show that the shrinkage in metal part is not uniform in the micro scale. It depends on the feature dimensions and also on the process conditions. A thin section of the part exhibits higher relative shrinkage compared with a thicker section. Based on these findings, it can be concluded that a micro part molded by MIM process will have higher relative shrinkage compared to a macro part made with the same process.

  5. EFFECTS OF INJECTION TEMPERATURE ON MECHANICAL PROPERTIES OF BAGASSE/POLYPROPYLENE INJECTION MOLDING COMPOSITES

    OpenAIRE

    Shinichi Shibata; Rahman M. Bozlur; Isao Fukumoto; Yasuyuki Kanda

    2010-01-01

    Effects of injection temperature on thermal degradation and porosity of the bagasse/polypropylene injection molding composites were studied. Above 185 ºC, incomplete filling occurred. The incomplete filling increased with increase of injection temperature. It was found that the gas generated by thermal degradation of bagasse fibers was so accumulated in the injection cylinder that the injected composites ended up with incomplete filling. A modified injection method with the venting of gas inc...

  6. Multiple Performance Optimization for the Best Metal Injection Molding Green Compact

    Directory of Open Access Journals (Sweden)

    M.R. Harun

    2011-01-01

    Full Text Available This study presents and demonstrates the effectiveness of optimizing multiple quality characteristics of the injection molding of the MIM green compacts via Taguchi method-based Grey analysis. The modified algorithm adopted here was successfully used for both detraining the optimum setting of the process parameters and for combining multiple quality characteristics into one integrated numerical value called Grey relational grade. The significant molding parameters were identified as (1 Injection Pressure (2 Injection Temperature (3 Powder Loading (4 Mold Temperature (5 Holding Pressure and (6 Injection Speed. In addition, the multiple quality characteristics required are: (1 less defects (2 strong and (3 denser compact. The result concluded that the powder loading (C is very significant for the combination of the quality characteristics.

  7. Bio-inspired piezoelectric artificial hair cell sensor fabricated by powder injection molding

    Science.gov (United States)

    Han, Jun Sae; Oh, Keun Ha; Moon, Won Kyu; Kim, Kyungseop; Joh, Cheeyoung; Seo, Hee Seon; Bollina, Ravi; Park, Seong Jin

    2015-12-01

    A piezoelectric artificial hair cell sensor was fabricated by the powder injection molding process in order to make an acoustic vector hydrophone. The entire process of powder injection molding was developed and optimized for PMN–PZT ceramic powder. The artificial hair cell sensor, which consists of high aspect ratio hair cell and three rectangular mechanoreceptors, was precisely fabricated through the developed powder injection molding process. The density and the dielectric property of the fabricated sensor shows 98% of the theoretical density and 85% of reference dielectric property of PMN–PZT ceramic powder. With regard to homogeneity, three rectangular mechanoreceptors have the same dimensions, with 3 ?m of tolerance with 8% of deviation of dielectric property. Packaged vector hydrophones measure the underwater acoustic signals from 500 to 800 Hz with ?212 dB of sensitivity. Directivity of vector hydrophone was acquired at 600 Hz as analyzing phase differences of electric signals.

  8. The Shrinkage Behavior and Surface Topographical Investigation for Micro Metal Injection Molding

    DEFF Research Database (Denmark)

    Islam, Aminul; Giannekas, Nikolaos; Marhöfer, David Maximilian; Tosello, Guido; Hansen, Hans Nørgaard

    2014-01-01

    especially when it is compared with micro molding of thermoplastics. The current paper presents a thorough investigation on the process of metal injection molding where it systematically characterizes the effects of important process conditions on the shrinkage and surface quality of molded parts with micro....... Among the different process parameters studied, the melt temperature was the most influential parameters for better replication and dimensional stability of the final part. The results presented in the paper clearly show that the shrinkage in metal part is not uniform in the micro scale. It depends on...... the feature dimensions and also on the process conditions. A thin section of the part exhibits higher relative shrinkage compared with a thicker section. Based on these findings, it can be concluded that a micro part molded by MIM process will have higher relative shrinkage compared to a macro part...

  9. Ion channel recordings on an injection-molded polymer chip

    DEFF Research Database (Denmark)

    Tanzi, Simone; Matteucci, Marco; Christiansen, Thomas Lehrmann; Friis, Søren; Christensen, Mette Thylstrup; Garnæs, Jørgen; Wilson, Sandra; Kutchinsky, Jonatan; Taboryski, Rafael

    2013-01-01

    In this paper, we demonstrate recordings of the ion channel activity across the cell membrane in a biological cell by employing the so-called patch clamping technique on an injection-molded polymer microfluidic device. The findings will allow direct recordings of ion channel activity to be made u...

  10. Fast prototyping of injection molded polymer microfluidic chips

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Selmeczi, David; Larsen, Niels Bent

    2010-01-01

    , likely due to the resulting reduction in sidewall steepness. We employed the latter method for injection molding bondable polymer microfluidic chips with integrated conducting polymer electrode arrays that permitted the culture and on-chip analysis of cell spreading by impedance spectroscopy....

  11. PHYSICAL PROPERTIES OF EXTRUDED AND INJECTION MOLDED CORN GLUTEN MEAL

    Science.gov (United States)

    This study was performed to investigate the compounding of corn gluten meal (CGM) and decanoic acid and to evaluate their mechanical properties. The mixture of CGM and 30% decanoic acid was compounded in a twin screw extruder, followed by injection molding. Scanning electron microscopy (SEM), tens...

  12. Fiber-Based, Injection-Molded Optofluidic Systems

    DEFF Research Database (Denmark)

    Matteucci, Marco; Triches, Marco; Nava, Giovanni; Kristensen, Anders; Pollard, Mark R.; Berg-Sørensen, Kirstine; Taboryski, Rafael J.

    2015-01-01

    We present a method to fabricate polymer optofluidic systems by means of injection molding that allow the insertion of standard optical fibers. The chip fabrication and assembly methods produce large numbers of robust optofluidic systems that can be easily assembled and disposed of, yet allow...

  13. Dimensional changes of acrylic resin denture bases: conventional versus injection-molding technique.

    Directory of Open Access Journals (Sweden)

    Jafar Gharechahi

    2014-08-01

    Full Text Available Acrylic resin denture bases undergo dimensional changes during polymerization. Injection molding techniques are reported to reduce these changes and thereby improve physical properties of denture bases. The aim of this study was to compare dimensional changes of specimens processed by conventional and injection-molding techniques.SR-Ivocap Triplex Hot resin was used for conventional pressure-packed and SR-Ivocap High Impact was used for injection-molding techniques. After processing, all the specimens were stored in distilled water at room temperature until measured. For dimensional accuracy evaluation, measurements were recorded at 24-hour, 48-hour and 12-day intervals using a digital caliper with an accuracy of 0.01 mm. Statistical analysis was carried out by SPSS (SPSS Inc., Chicago, IL, USA using t-test and repeated-measures ANOVA. Statistical significance was defined at P<0.05.After each water storage period, the acrylic specimens produced by injection exhibited less dimensional changes compared to those produced by the conventional technique. Curing shrinkage was compensated by water sorption with an increase in water storage time decreasing dimensional changes.Within the limitations of this study, dimensional changes of acrylic resin specimens were influenced by the molding technique used and SR-Ivocap injection procedure exhibited higher dimensional accuracy compared to conventional molding.

  14. Simulation and measurement of optical aberrations of injection molded progressive addition lenses.

    Science.gov (United States)

    Li, Likai; Raasch, Thomas W; Yi, Allen Y

    2013-08-20

    Injection molding is an important mass-production tool in the optical industry. In this research our aim is to develop a process of combining ultraprecision diamond turning and injection molding to create a unique low-cost manufacturing process for progressive addition lenses (PALs). In industry, it is a well-known fact that refractive index variation and geometric deformation of injection molded lenses due to the rheological properties of polymers will distort their optical performance. To address this problem, we developed a method for determining the optical aberrations of the injection molded PALs. This method involves reconstructing the wavefront pattern in the presence of uneven refractive index distribution and surface warpage using a finite element method. In addition to numerical modeling, a measurement system based on a Shack-Hartmann wavefront sensor was used to verify the modeling results. The measured spherocylindrical powers and aberrations of the PALs were in good agreement with the model. Consequently, the optical aberrations of injection molded PALs were successfully predicted by finite element modeling. In summary, it was demonstrated in this study that numerically based optimization for PAL manufacturing is feasible. PMID:24085007

  15. Effects of Process Parameters on Replication Accuracy of Microinjection Molded Cyclic Olefins Copolymers Parts

    Science.gov (United States)

    Lin, Hsuan-Liang; Chen, Chun-Sheng; Lee, Ruey-Tsung; Chen, Shia-Chung; Chien, Rean-Der; Jeng, Ming-Chang; Hwang, Jiun-Ren

    2013-04-01

    In this study, the effects of various processing parameters of microinjection molding on the replication accuracy of the micro featured fluidic platform used for DNA/RNA tests are investigated. LIGA-like processes were utilized to prepare a silicon-based SU-8 photoresist, followed by electroforming to make a Ni-Co-based stamp. A cyclic olefin copolymer (COC) was used as the injection molding material. The molding parameters associated with the replication accuracy of micro channel parts were investigated. It was found that for microinjection molded devices, the replication accuracies of the imprint width and depth increase with increasing of mold temperature, melt temperature, injection velocity, and packing pressure.

  16. Localized mold heating with the aid of selective induction for injection molding of high aspect ratio micro-features

    International Nuclear Information System (INIS)

    High-frequency induction is an efficient, non-contact means of heating the surface of an injection mold through electromagnetic induction. Because the procedure allows for the rapid heating and cooling of mold surfaces, it has been recently applied to the injection molding of thin-walled parts or micro/nano-structures. The present study proposes a localized heating method involving the selective use of mold materials to enhance the heating efficiency of high-frequency induction heating. For localized induction heating, a composite injection mold of ferromagnetic material and paramagnetic material is used. The feasibility of the proposed heating method is investigated through numerical analyses in terms of its heating efficiency for localized mold surfaces and in terms of the structural safety of the composite mold. The moldability of high aspect ratio micro-features is then experimentally compared under a variety of induction heating conditions.

  17. FPGA-Based Multiprocessor System for Injection Molding Control

    Directory of Open Access Journals (Sweden)

    Roque A. Osornio-Rios

    2012-10-01

    Full Text Available The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic controller, a system manager, an IO processor and a communication processor. Temperature, pressure and position are controlled by the proposed system and experimentation results show its feasibility and robustness. As validation of the present work, a particular sample was successfully injected.

  18. FPGA-based multiprocessor system for injection molding control.

    Science.gov (United States)

    Muñoz-Barron, Benigno; Morales-Velazquez, Luis; Romero-Troncoso, Rene J; Rodriguez-Donate, Carlos; Trejo-Hernandez, Miguel; Benitez-Rangel, Juan P; Osornio-Rios, Roque A

    2012-01-01

    The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA) device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic controller, a system manager, an IO processor and a communication processor. Temperature, pressure and position are controlled by the proposed system and experimentation results show its feasibility and robustness. As validation of the present work, a particular sample was successfully injected. PMID:23202036

  19. Hot mold casting process of ancient East India and Bangladesh

    OpenAIRE

    Barnali Mandal; Prasanta Kumar Datta

    2010-01-01

    Ancient casting process for production of brass or bronze utensils and icons were made in hot molds using clay molded investment casting or piece mold process, as presumed by archaeologists. Piece mold process is still traditionally practiced in many parts of Eastern India and Bangladesh along with investment casting process. Incidentally, Bengal artisans are more accustomed to piece mold process unlike tribal artisans who practiced investment casting process. This piece mold casting process ...

  20. Microinjection molding of thermoplastic polymers: morphological comparison with conventional injection molding

    International Nuclear Information System (INIS)

    The skin–core crystalline morphology of injection-molded semi-crystalline polymers is well documented in the scientific literature. The thermomechanical environment provokes temperature and shear gradients throughout the entire thickness of the part during molding, thus influencing the polymer crystallization. Crystalline morphologies of a high-density polyethylene (HDPE) micromolded part (?part) and a classical part (macropart) are compared with optical, thermal and x-ray diffraction analyses. Results show that the crystalline morphologies with regard to thickness vary between the two parts. While a 'skin–core' morphology is present for the macropart, the ?part exhibits a specific 'core-free' morphology, i.e. no spherulite is present at the center of the thickness. This result seems to be generated under the specific conditions used in microinjection molding that lead to the formation of smaller and more oriented crystalline entities

  1. Microinjection molding of thermoplastic polymers: morphological comparison with conventional injection molding

    Science.gov (United States)

    Giboz, Julien; Copponnex, Thierry; Mélé, Patrice

    2009-02-01

    The skin-core crystalline morphology of injection-molded semi-crystalline polymers is well documented in the scientific literature. The thermomechanical environment provokes temperature and shear gradients throughout the entire thickness of the part during molding, thus influencing the polymer crystallization. Crystalline morphologies of a high-density polyethylene (HDPE) micromolded part (?part) and a classical part (macropart) are compared with optical, thermal and x-ray diffraction analyses. Results show that the crystalline morphologies with regard to thickness vary between the two parts. While a 'skin-core' morphology is present for the macropart, the ?part exhibits a specific 'core-free' morphology, i.e. no spherulite is present at the center of the thickness. This result seems to be generated under the specific conditions used in microinjection molding that lead to the formation of smaller and more oriented crystalline entities.

  2. Dimensional Changes of Acrylic Resin Denture Bases: Conventional Versus Injection-Molding Technique

    Science.gov (United States)

    Gharechahi, Jafar; Asadzadeh, Nafiseh; Shahabian, Foad; Gharechahi, Maryam

    2014-01-01

    Objective: Acrylic resin denture bases undergo dimensional changes during polymerization. Injection molding techniques are reported to reduce these changes and thereby improve physical properties of denture bases. The aim of this study was to compare dimensional changes of specimens processed by conventional and injection-molding techniques. Materials and Methods: SR-Ivocap Triplex Hot resin was used for conventional pressure-packed and SR-Ivocap High Impact was used for injection-molding techniques. After processing, all the specimens were stored in distilled water at room temperature until measured. For dimensional accuracy evaluation, measurements were recorded at 24-hour, 48-hour and 12-day intervals using a digital caliper with an accuracy of 0.01 mm. Statistical analysis was carried out by SPSS (SPSS Inc., Chicago, IL, USA) using t-test and repeated-measures ANOVA. Statistical significance was defined at Presin specimens were influenced by the molding technique used and SR-Ivocap injection procedure exhibited higher dimensional accuracy compared to conventional molding. PMID:25584050

  3. Cooling effects study by considering a turbulence model in injection molding

    Science.gov (United States)

    Hsu, Fu-Hung; Wu, Bo-Han; Huang, Chao-Tsai; Chang, Rong-Yeu

    2014-05-01

    Cooling stage is critical in injection molding process. A well designed cooling system can effectively shorten cycle time and improve product quality. Three-dimensional cooling analysis has been embedded in injection molding simulation which provides a useful tool for cooling system design validation. However, the current simulation tool is not perfect yet since it does not consider turbulent flow and pipe surface roughness effect. In the current study, a latest simulation tool was applied which can predict the turbulent flow effect on cooling. Two cooling systems (conventional and conformal) were simulated and compared to each other. Turbulence model and surface roughness effects were also studied. The simulation results show a good agreement with experimental data which is helpful at the design stage of an injection molding cooling system.

  4. Injection molded pinched flow fractionation device for enrichment of somatic cells in cow milk

    DEFF Research Database (Denmark)

    Jensen, Marie PØdenphant; Marie, Rodolphe

    2014-01-01

    In this paper the continuous microfluidic separation technique pinched flow fractionation is applied to the enrichment of somatic cells from cow milk. Somatic cells were separated from the smallest fat particles and proteins thus better imaging and analysis of the cells can be achieved. The enrichment was performed using an all-polymer pinched flow fractionation device fabricated by injection molding. The polymer chips were bonded to a 500 lm polymer foil using UV assisted thermal bonding. The quality of the final devices was reproducible and the injection molding process combined with the use of cheap materials ensures the possibility for device mass production

  5. Análise do desenvolvimento morfológico da blenda polimérica PBT/ABS durante as etapas de mistura por extrusão e moldagem por injeção Analysis of the morphological development of PBT/ABS blends during the extrusion and injection molding processes

    Directory of Open Access Journals (Sweden)

    Edson N. Ito

    2004-06-01

    Full Text Available O enfoque principal deste trabalho foi observar o desenvolvimento da morfologia de fases da blenda binária PBT/ABS e desta blenda compatibilizada pela adição de um copolímero acrílico reativo, durante a etapa de mistura por extrusão e de moldagem por injeção. A evolução da morfologia das blendas, durante a etapa de mistura, foi analisada através do uso de amostras coletadas de uma extrusora de rosca dupla co-rotacional, com acessório especialmente projetado para coleta in line. A morfologia observada nas amostras obtidas por injeção foi realizada utilizando amostras retiradas de corpos de prova moldados. As amostras obtidas por extrusão e por moldagem por injeção foram posteriormente preparadas através de crio-ultramicrotomia e observadas através de microscopia eletrônica de transmissão (TEM. Uma "Função Dispersão" foi desenvolvida neste trabalho para comparar as diversas morfologias sob diferentes condições de processamento e de compatibilização. A adição de compatibilizante favorece a formação de uma morfologia de domínios de ABS dispersos em PBT, ao longo do canhão da extrusora, e previne satisfatoriamente o fenômeno de coalescência destes domínios durante o processo de moldagem por injeção. A função dispersão foi utilizada principalmente para mostrar a tendência da evolução morfológica e mostrou um bom desempenho para tal.The aim of this work was to observe the development of the phase morphology of the PBT/ABS blends during their extrusion mixing and injection molding steps. The evolution of the blend morphology during the mixing stage was analyzed using a specially designed co-rotational twin-screw extruder with a collecting device located along the barrel. Blend samples were collected in-line along the length of the extruder barrel during the blending process. Blend morphology was also observed from specimens molded through injection molding. All the samples were observed by transmission electron microscopy (TEM. They were prepared by cryo-ultramicrotomy and the rubbery phase of the ABS contained in the blends was stained with osmium tetroxide (OsO4. A special function was established and is proposed to analyze the blend morphology trends through image analysis. In binary blends, the ABS phase showed better dispersion after the mixture passed through the extruder die. However, a coalescence phenomenon was observed during the next molding step. Compatibilized PBT/ABS blends showed better dispersion than binary blends, even after injection molding. The special function used to quantify the dispersion throughout the mixing and molding steps showed an excellent performance.

  6. Análise do desenvolvimento morfológico da blenda polimérica PBT/ABS durante as etapas de mistura por extrusão e moldagem por injeção / Analysis of the morphological development of PBT/ABS blends during the extrusion and injection molding processes

    Scientific Electronic Library Online (English)

    Edson N., Ito; Luiz A., Pessan; Elias, Hage Jr.; José A., Covas.

    2004-06-01

    Full Text Available O enfoque principal deste trabalho foi observar o desenvolvimento da morfologia de fases da blenda binária PBT/ABS e desta blenda compatibilizada pela adição de um copolímero acrílico reativo, durante a etapa de mistura por extrusão e de moldagem por injeção. A evolução da morfologia das blendas, du [...] rante a etapa de mistura, foi analisada através do uso de amostras coletadas de uma extrusora de rosca dupla co-rotacional, com acessório especialmente projetado para coleta in line. A morfologia observada nas amostras obtidas por injeção foi realizada utilizando amostras retiradas de corpos de prova moldados. As amostras obtidas por extrusão e por moldagem por injeção foram posteriormente preparadas através de crio-ultramicrotomia e observadas através de microscopia eletrônica de transmissão (TEM). Uma "Função Dispersão" foi desenvolvida neste trabalho para comparar as diversas morfologias sob diferentes condições de processamento e de compatibilização. A adição de compatibilizante favorece a formação de uma morfologia de domínios de ABS dispersos em PBT, ao longo do canhão da extrusora, e previne satisfatoriamente o fenômeno de coalescência destes domínios durante o processo de moldagem por injeção. A função dispersão foi utilizada principalmente para mostrar a tendência da evolução morfológica e mostrou um bom desempenho para tal. Abstract in english The aim of this work was to observe the development of the phase morphology of the PBT/ABS blends during their extrusion mixing and injection molding steps. The evolution of the blend morphology during the mixing stage was analyzed using a specially designed co-rotational twin-screw extruder with a [...] collecting device located along the barrel. Blend samples were collected in-line along the length of the extruder barrel during the blending process. Blend morphology was also observed from specimens molded through injection molding. All the samples were observed by transmission electron microscopy (TEM). They were prepared by cryo-ultramicrotomy and the rubbery phase of the ABS contained in the blends was stained with osmium tetroxide (OsO4). A special function was established and is proposed to analyze the blend morphology trends through image analysis. In binary blends, the ABS phase showed better dispersion after the mixture passed through the extruder die. However, a coalescence phenomenon was observed during the next molding step. Compatibilized PBT/ABS blends showed better dispersion than binary blends, even after injection molding. The special function used to quantify the dispersion throughout the mixing and molding steps showed an excellent performance.

  7. Injection molding micro patterns with high aspect ratio using a polymeric flexible stamper

    Directory of Open Access Journals (Sweden)

    2011-11-01

    Full Text Available Poor filling occurs during the injection molding process of micro- or nano- scale patterns mainly because the hot polymer melt rapidly cools and its skin quickly solidifies upon contact with the mold surface. In this study, it is proposed to use Polyethylene terephthalate (PET film coated with patterned polyurethane acrylate (PUA as an effective thermal barrier. It can significantly hinder heat transfer into the mold during the molding process and thus may keep the melt viscosity low for longer duration. As a result, the replication would be improved not only during the filling phase but also during the packing phase. In order to verify the validity of the use of polymeric stamper, the melt-film interface temperature was evaluated by numerical simulation. Experimental results indicated that patterns possessing widths within the range of one to tens of micrometers and a height of approximately 10 µm were successfully filled and demolded.

  8. Metal Injection Molding (MIM of NdFeB Magnets

    Directory of Open Access Journals (Sweden)

    Hartwig T.

    2014-07-01

    Full Text Available Due to the increased and unstable prices for Rare Earth elements there are activities to develop alternative hard magnetic materials. Reducing the amount of material necessary to produce complex sintered NdFeB magnets can also help to reduce some of the supply problem. Metal Injection Molding (MIM is able to produce near net shape parts and can reduce the amount of finishing to achieve final geometry. Although MIM of NdFeB has been patented and published fairly soon after the development of the NdFeB magnets there has never been an industrial production. This could be due to the fact that MIM was very young at that time and hardly developed. Thus, the feasibility of the process needs to be revaluated. This paper presents results of our work on determining the process parameters influencing the magnetic properties of the sintered magnets as well as the shrinkage during processing. The role of binder and powder loading on the alignment of the particles as well as on the carbon and oxygen contamination was examined.

  9. Metal Injection Molding (MIM) of NdFeB Magnets

    Science.gov (United States)

    Hartwig, T.; Lopes, L.; Wendhausen, P.; Ünal, N.

    2014-07-01

    Due to the increased and unstable prices for Rare Earth elements there are activities to develop alternative hard magnetic materials. Reducing the amount of material necessary to produce complex sintered NdFeB magnets can also help to reduce some of the supply problem. Metal Injection Molding (MIM) is able to produce near net shape parts and can reduce the amount of finishing to achieve final geometry. Although MIM of NdFeB has been patented and published fairly soon after the development of the NdFeB magnets there has never been an industrial production. This could be due to the fact that MIM was very young at that time and hardly developed. Thus, the feasibility of the process needs to be revaluated. This paper presents results of our work on determining the process parameters influencing the magnetic properties of the sintered magnets as well as the shrinkage during processing. The role of binder and powder loading on the alignment of the particles as well as on the carbon and oxygen contamination was examined.

  10. Modeling morphology evolution during injection molding of thermoplastic polymers

    Science.gov (United States)

    Pantani, R.; De Santis, F.; Speranza, V.; Titomanlio, G.

    2015-05-01

    The effect of temperature, pressure and flow on relaxation time (or spectrum), crystallization time, nucleation density and rate, spherulite growth rate, the interrelation among these quantities and the distributions of deformation rate and cooling time during the process all together determine the morphology distribution in the final object. A simple model linking all these quantities was developed to describe morphology evolution during polymer processing. The effect of flow on nucleation density and growth rate of an isotactic polypropylene (iPP) is described on the basis of a molecular stretch parameter and the stretch evolution is described by a simple nonlinear Maxwell model, whose relaxation time, in its turn, is determined by the molecular stretch and, obviously, temperature pressure and crystallinity [1]. The model is applied to the description of morphology evolution during the injection molding process of a very accurately characterized iPP as far as rheology, quiescent crystallization and effect of flow on nucleation and spherulitic growth rates. Main characteristics of final morphology are reproduced by the simulations.

  11. Single Performance Optimization of Micro Metal Injection Molding for the Highest Green Strength by Using Taguchi Method

    Directory of Open Access Journals (Sweden)

    M.H.I Ibrahim

    2010-06-01

    Full Text Available Micro metal injection molding is drawing attention recently as one the most cost effective processes in powder metallurgy to produce small-scale intricate part and competitive cost for mass production of micro components where it is greatly influenced by injection parameter. Thus, this paper investigated the optimization of highest green strength which plays an important characteristic in determining the successful of micro MIM. Stainless steel SS 316L was used with composite binder, which consists of PEG and PMMA while SA works as a surfactant. Feedstock with 61.5% with several injection parameters were optimized which highly significant through screening experiment such as injection pressure(A, injection temperature(B, mold temperature(C, injection time(D and holding time(E. Besides that, interaction effects between injection pressure, injection temperature and mold temperature were also considered to optimize in the Taguchi’s orthogonal array. Analysis of variance (ANOVA in terms of signal-to-noise ratio (S/N-larger is better for green strength was also presented in this paper. Result shows that interaction between injection temperature and mold temperature (BxC give highest significant factor followed by interaction between injection pressure and injection temperature (AxB. Single factor that also contributes to significant optimization are mold temperature(C, injection time (D and injection pressure (A. Overall, this study shows that Taguchi method would be among the best method to solve the problem with minimum number of trials.

  12. Micro Machining of Injection Mold Inserts for Fluidic Channel of Polymeric Biochips

    Directory of Open Access Journals (Sweden)

    Myeong-Woo Cho

    2007-08-01

    Full Text Available Recently, the polymeric micro-fluidic biochip, often called LOC (lab-on-a-chip, has been focused as a cheap, rapid and simplified method to replace the existing biochemical laboratory works. It becomes possible to form miniaturized lab functionalities on a chip with the development of MEMS technologies. The micro-fluidic chips contain many micro-channels for the flow of sample and reagents, mixing, and detection tasks. Typical substrate materials for the chip are glass and polymers. Typical techniques for micro-fluidic chip fabrication are utilizing various micro pattern forming methods, such as wet-etching, micro-contact printing, and hot-embossing, micro injection molding, LIGA, and micro powder blasting processes, etc. In this study, to establish the basis of the micro pattern fabrication and mass production of polymeric micro-fluidic chips using injection molding process, micro machining method was applied to form micro-channels on the LOC molds. In the research, a series of machining experiments using micro end-mills were performed to determine optimum machining conditions to improve surface roughness and shape accuracy of designed simplified micro-channels. Obtained conditions were used to machine required mold inserts for micro-channels using micro end-mills. Test injection processes using machined molds and COC polymer were performed, and then the results were investigated.

  13. Pressureless sintering behavior of injection molded alumina ceramics

    Directory of Open Access Journals (Sweden)

    Liu W.

    2014-01-01

    Full Text Available The pressureless sintering behaviors of two widely used submicron alumina (MgOdoped and undoped with different solid loadings produced by injection molding have been studied systematically. Regardless of the sinterability of different powders depending on their inherent properties, solid loading plays a critical role on the sintering behavior of injection molded alumina, which greatly determines the densification and grain size, and leads to its full densification at low temperatures. As compared to the MgO-doped alumina powder, the undoped specimens exhibit a higher sinterability for its smaller particle size and larger surface area. While full densification could be achieved for MgO-doped powders with only a lower solid loading, due to the fact that MgO addition can reduce the detrimental effect of the large pore space on the pore-boundary separation.

  14. On the Injection Molding of Nanostructured Polymer Surfaces

    DEFF Research Database (Denmark)

    Pranov, Henrik; Rasmussen, Henrik K.; Larsen, Niels Bent; Gadegaard, Nikolaj

    2006-01-01

    Well-defined nano-topographies were prepared by electron-beam lithography and electroplated to form nickelshims. The surface pattern consisted of square pillars repeated equidistantly within the plane of the surface in a perpendicular arrangement. The width and distance between the squares both ranged from 310 to 3100 rim. All the pillars were 220 nm high. The nickel-shim was used as a surface-template during injection molding of polycarbonate. Secondly, a nickel shim, with a surface pattern con...

  15. Study of microcellular injection-molded polypropylene/waste ground rubber tire powder blend

    International Nuclear Information System (INIS)

    Microcellular polypropylene/waste ground rubber tire powder blend processing was performed on an injection-molding machine with a chemical foaming agent. The molded samples produced based on the design of experiments (DOE) matrices were subjected to tensile testing and scanning electron microscope (SEM) analyses. Molding conditions and waste ground rubber tire (WGRT) powder have been found to have profound effects on the cell structures and mechanical properties of polypropylene (PP) and waste ground rubber tire powder composite samples. The result shows that microcellular PP/WGRT blend samples exhibit smaller cell size and higher cell density compare with polypropylene resin. Among the molding parameters studied, chemical foaming agent weight percentage has the most significant effect on cell size, cell density, and tensile strength. The results also suggest that tensile strength of microcellular PP/WGRT composites is sensitive to weight reduction, and skin thickness.

  16. Reinforcement and structure development in injection molding of bone-analogue composites

    OpenAIRE

    Sousa, R.A; R. L. Reis; Cunha, A. M.; Bevis, M. J.

    2002-01-01

    Composites of high density polyethylene (HDPE) with hydroxyapatite (HA—the main inorganic constituent of human bone) were produced by extrusion compounding and subsequent injection molding. Shear controlled orientation in injection molding (SCORIM) was used deliberately to induce a strong anisotropic character in the composite materials. Bi-composite moldings featuring a sandwich like morphology were also produced by mono-sandwich injection molding. These composites combine ...

  17. Experimental Study of Fiber Length and Orientation in Injection Molded Natural Fiber/Starch Acetate Composites

    DEFF Research Database (Denmark)

    Peltola, Heidi; Madsen, Bo; Joffe, Roberts; Nättinen, Kalle

    2011-01-01

    Composite compounds based on triethyl citrate plasticized starch acetate and hemp and flax fibers were prepared by melt processing. Plasticizer contents from 20 to 35 wt% and fiber contents of 10 and 40 wt% were used. The compounded composites were injection molded to tensile test specimens. The ...

  18. Initial verification of an induction heating set-up for injection molding

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans NØrgaard

    2013-01-01

    Molding of thin and long parts by injection molding leads to special requirements for the mold in order to ensure proper filling and acceptable cycle time. This paper investigates the applicability of embedded induction heating for the improvement of the filling of thin long parts. The object selected for the investigation is a thin spiral. For the complete molding of the component, elevated mold temperatures are required. For this propose a new injection molding set-up was developed, which allows rapid heating of the cavity wall by an induction heating system. The temperature was measured by two thermocouples placed in the die insert. The system was used to heat up the cavity wall with heating rates of up to 10 °C/s. Experiments were carried out with ABS material. The lengths of the object were measured by a suitable measurement set up. The experimental result show that the use of the induction heating system process is an efficient way for improving the filling of the cavity.

  19. Integrated mold/surface-micromachining process

    Energy Technology Data Exchange (ETDEWEB)

    Barron, C.C.; Fleming, J.G.; Montague, S.; Sniegowski, J.J.; Hetherington, D.L.

    1996-03-01

    We detail a new monolithically integrated silicon mold/surface-micromachining process which makes possible the fabrication of stiff, high-aspect-ratio micromachined structures integrated with finely detailed, compliant structures. An important example, which we use here as our process demonstration vehicle, is that of an accelerometer with a large proof mass and compliant suspension. The proof mass is formed by etching a mold into the silicon substrate, lining the mold with oxide, filling it with mechanical polysilicon, and then planarizing back to the level of the substrate. The resulting molded structure is recessed into the substrate, forming a planar surface ideal for subsequent processing. We then add surface-micromachined springs and sense contacts. The principal advantage of this new monolithically integrated mold/surface-micromachining process is that it decouples the design of the different sections of the device: In the case of a sensitive accelerometer, it allows us to optimize independently the proof mass, which needs to be as large, stiff, and heavy as possible, and the suspension, which needs to be as delicate and compliant as possible. The fact that the high-aspect-ratio section of the device is embedded in the substrate enables the monolithic integration of high-aspect-ratio parts with surface-micromachined mechanical parts, and, in the future, also electronics. We anticipate that such an integrated mold/surface micromachining/electronics process will offer versatile high-aspect-ratio micromachined structures that can be batch-fabricated and monolithically integrated into complex microelectromechanical systems.

  20. A Simulation Study of Conformal Cooling Channels in Plastic Injection Molding

    Directory of Open Access Journals (Sweden)

    Omar A. Mohamed, S.H. Masood, Abul Saifullah

    2013-09-01

    Full Text Available In injection molding process, the cooling channel performance is one of the most crucial factors because it has significant effect on both production rate and the quality of the plastic part. In order to reduce the cycle time, and control the uniform distribution of temperature, it is necessary to create conformal cooling channels, which conform to the shape of the mold cavity and core. This paper presents a simulation study of different types of cooling channels in an injection molded plastic part and compares the performance in terms of time to ejectiontemperature, shrinkage, temperature profile, and part warpage to determine which configuration is more appropriate to provide uniform cooling with minimum cycle time. Autodesk Moldflow Insight (AMI simulation software is used to examine the results of the cooling channels performance.

  1. Powder Injection Molding of Ceria-Stabilized, Zirconia-Toughened Mullite Parts for UAV Engine Components

    Science.gov (United States)

    Martin, Renee; Vick, Michael; Enneti, Ravi K.; Atre, Sundar V.

    2013-11-01

    Powder injection molding (PIM) of ceria-stabilized, zirconia-toughened mullite composites were investigated in the present article with the goal of obtaining performance enhancement in complex geometries for energy and transportation applications. A powder-polymer mixture (feedstock) was developed and characterized to determine its suitability for fabricating complex components using the PIM process. Test specimens were injection molded and subsequently debound and sintered. The sintered properties indicated suitable properties for engine component applications used in unmanned aerial vehicles (UAVs). The measured feedstock properties were used in computer simulations to assess the mold-filling behavior for a miniature turbine stator. The results from the measurements of rheological and thermal properties of the feedstock combined with the sintered properties of the ceria-stabilized, zirconia-toughened mullite strongly indicate the potential for enhancing the performance of complex geometries used in demanding operating conditions in UAV engines.

  2. Carbon Nanotubes Reinforced Copper Matrix Nanocomposites via Metal Injection Molding Technique

    Directory of Open Access Journals (Sweden)

    Norani M. Mohamed

    2012-01-01

    Full Text Available New thermal management solutions are required to provide cost-effective means of dissipating heat from next generation microelectronic devices. In this paper, fabrication of heat sink nanocomposite made of copper reinforced by multiwalled carbon nanotubes up to 10 Vol. % using metal injection molding technique is presented. A mixture of Cu-MWNTs was compounded using internal mixer machine for homogenous dispersion of the solid powder in the binder. To ensure a flow able feedstock during injection molding process, different binder systems and their Cu-MWNTs feedstocks were examined using capillary rheometer machine. In order to avoid binder degradation, TGA test was carried out. The TGA results showed that the processing temperature such as mixing and injection molding should be lower than 170°C. The injection molding was carried out at low pressure. A combination of solvent and thermal debinding was used for binder removal, and then the samples were isothermally sintered at different sintering temperatures (900-1050°C in argon atmosphere. The results showed that the sintered samples experienced an isotropic shrinkage around 17% with relatively homogeneous dispersion of MWNTs in the copper matrix which is expected to enhance the physical and mechanical properties of the final product.

  3. Near net shaping of Nb-Al injection molded compacts using pulse current sintering process under pseudo hot isostatic pressing; Gi HIP-hoden shoketsuho ni yoru Nb-Al shashutsu seikeitai no near net shape koka gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, A.; Kato, K.; Kato, M. [National Industrial Research Institute of Nagoya,Nagoya (Japan)

    1999-02-22

    The consolidation of injection molded Nb-Al specimen by Pulse Current Sintering Process, that combines a very short time at high temperature with pressure application in various environments, is proposed as a novel process of near net forming(PHIP-PCS). The proposed PHIP technique using a pressure-transmitting medium of spherical graphite powder makes it possible to manufacture Nb-Al compacts with three dimensional shapes. Fine Nb{sub 3}Al powders, Nb-23at%Al, Nb-26at%Al-37at%Mo and Nb-27at%Al-31.5at%Mo-10W (hereafter at% being omitted), with A15 structure, were prepared by self-propagating high temperature synthesis method. The powders, mixed with 44 vol% organic binder, were injection molded. After debound in 100 Torr Ar atmosphere at 380 degree C, they were consolidated by PHIP-PCS process. Contraction percentage of the compacts prepared by PHIP-PCS was 36% for longitudinal (loading) direction, while 1% for transverse direction. Compressive flow stress at 1,800 degree C for Nb-23Al, Nb-26Al-37Mo and Nb-27Al-31.5Mo-10W compacts were respectively 27MPa, 65MPa and 95MPa.. (author)

  4. Advancements on the simulation of the micro injection moulding process

    DEFF Research Database (Denmark)

    Marhöfer, David Maximilian; Tosello, Guido

    2013-01-01

    Process simulations are applied in micro injection molding with the same purpose as in conventional injection molding: aiming at optimization and support of the design of mold, inserts, plastic products, and the process itself. Available software packages are however not well suited for micro injection molding, because they are developed for macro plastic parts and they are therefore limited in the capability of modeling the polymer flow in micro cavities properly. However, new opportunities for improved accuracy have opened up due to current developments of the simulation technology. Hence, new strategies and aspects for comprehensive simulation models which provide more precise results for micro injection molding are discussed. Modeling and meshing recommendations are presented, leading to a multi-scale mesh of all relevant units in the injection molding process. The implementation of the process boundary conditions is described, being followed by results illustrating their importance on the simulation output. Finally, the influence of the cooling simulation settings is analyzed.

  5. A review on the importance of surface coating of micro/nano-mold in micro/nano-molding processes

    Science.gov (United States)

    Saha, Biswajit; Toh, Wei Quan; Liu, Erjia; Beng Tor, Shu; Hardt, David E.; Lee, Junghoon

    2016-01-01

    Micro/nano hot-embossing and injection molding are two promising manufacturing processes for the mass production of workpieces bearing micro/nanoscale features. However, both the workpiece and micro/nano-mold are susceptive to structural damage due to high thermal stress, adhesion and friction, which occur at the interface between the workpiece and the mold during these processes. Hence, major constraints of micro/nano-molds are mainly attributed to improper replication and their inability to withstand a prolonged sliding surface contact because of high sidewall friction and/or high adhesion. Consequently, there is a need for proper surface coating as it can improve the surface properties of micro/nano-molds such as having a low friction coefficient, low adhesion and low wear rate. This review deals with the physical, mechanical and tribological properties of various surface coatings and their impact on the replication efficiency and lifetime of micro/nano-molds that are used in micro/nano hot-embossing and injection molding processes.

  6. A Review of Effects of Molding Methods, Mold Thickness and Other Processing Parameters on Fiber Orientation in Polymer Composites

    OpenAIRE

    Ahmed N. Oumer; Othman Mamat

    2013-01-01

    In injection molded fiber reinforced composites, the mechanical and physical properties of the final product are highly dependent on the patterns of fibers alignment. The orientation of the fibers can be influenced by many factors such as molding methods, materials used, geometry of the part and other processing parameters. Thus, there is considerable interest in studying the factors that affect the fiber orientation, hence the properties of the final product. This study presented a gen...

  7. Micro Injection Molding of Thin Walled Geometries with Induction Heating System

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano; Grev, Nathaniel Ryan; Tang, Peter Torben

    2014-01-01

    To eliminate defects and improve the quality of molded parts, increasing the mold temperature is one of the applicable solutions. A high mold temperature can increase the path flow of the polymer inside the cavity allowing reduction of the number of injection points, reduction of part thickness and moulding of smaller and more complex geometries. The last two aspects are very important in micro injection molding. In this paper a new embedded induction heating system is proposed and validated. An...

  8. Aplicação de redes Neuro Fuzzy ao processamento de peças automotivas por meio de injeção de polímeros / Application of neurofuzzy networks for the processing of automotive parts by polymer injection molding

    Scientific Electronic Library Online (English)

    Carlos de Oliveira, Affonso; Renato José, Sassi.

    Full Text Available O processamento de peças automotivas por meio de injeção de polímeros envolve vários fenômenos físicos que ocorrem simultaneamente e que possuem caráter não linear e multivariável. Softwares comerciais podem ser utilizados na previsão dos parâmetros do processo, o que pode ser caro e inviável. Pode- [...] se determinar os parâmetros de forma analítica, mas o tratamento desse problema requer a aplicação de teorias clássicas dos fenômenos de transporte, de difícil equacionamento. As redes NeuroFuzzy são aplicáveis a esse problema porque reúnem a capacidade de aprender das redes neurais artificiais com a capacidade da lógica Fuzzy de transformar variáveis linguísticas em regras. Neste trabalho combinou-se uma rede neural artificial Multilayer Perceptron e uma rede neural artificial Radial Basis Function à lógica Fuzzy para construir-se um modelo de inferência que previu o tempo de ciclo de processos de injeção de polímeros. Os resultados obtidos confirmam as redes NeuroFuzzy como opção para esse tipo de problema. Abstract in english The injection molding of automotive parts is a complex process due to the many non-linear and multivariable phenomena that occur simultaneously. Commercial software applications exist for modeling the parameters of polymer injection but can be prohibitively expensive. It is possible to identify thes [...] e parameters analytically, but applying classical theories of transport phenomena requires accurate information about the injection machine, product geometry, and process parameters. However, neurofuzzy networks, which achieve a synergy by combining the learning capabilities of an artificial neural network with a fuzzy set's inference mechanism, have shown success in this field. The purpose of this paper was to use a multilayer perceptron artificial neural network and a radial basis function artificial neural network combined with fuzzy sets to produce an inference mechanism that could predict injection mold cycle times. The results confirmed neurofuzzy networks as an effective alternative to solving such problems.

  9. Aplicação de redes Neuro Fuzzy ao processamento de peças automotivas por meio de injeção de polímeros / Application of neurofuzzy networks for the processing of automotive parts by polymer injection molding

    Scientific Electronic Library Online (English)

    Carlos de Oliveira, Affonso; Renato José, Sassi.

    2015-03-01

    Full Text Available O processamento de peças automotivas por meio de injeção de polímeros envolve vários fenômenos físicos que ocorrem simultaneamente e que possuem caráter não linear e multivariável. Softwares comerciais podem ser utilizados na previsão dos parâmetros do processo, o que pode ser caro e inviável. Pode- [...] se determinar os parâmetros de forma analítica, mas o tratamento desse problema requer a aplicação de teorias clássicas dos fenômenos de transporte, de difícil equacionamento. As redes NeuroFuzzy são aplicáveis a esse problema porque reúnem a capacidade de aprender das redes neurais artificiais com a capacidade da lógica Fuzzy de transformar variáveis linguísticas em regras. Neste trabalho combinou-se uma rede neural artificial Multilayer Perceptron e uma rede neural artificial Radial Basis Function à lógica Fuzzy para construir-se um modelo de inferência que previu o tempo de ciclo de processos de injeção de polímeros. Os resultados obtidos confirmam as redes NeuroFuzzy como opção para esse tipo de problema. Abstract in english The injection molding of automotive parts is a complex process due to the many non-linear and multivariable phenomena that occur simultaneously. Commercial software applications exist for modeling the parameters of polymer injection but can be prohibitively expensive. It is possible to identify thes [...] e parameters analytically, but applying classical theories of transport phenomena requires accurate information about the injection machine, product geometry, and process parameters. However, neurofuzzy networks, which achieve a synergy by combining the learning capabilities of an artificial neural network with a fuzzy set's inference mechanism, have shown success in this field. The purpose of this paper was to use a multilayer perceptron artificial neural network and a radial basis function artificial neural network combined with fuzzy sets to produce an inference mechanism that could predict injection mold cycle times. The results confirmed neurofuzzy networks as an effective alternative to solving such problems.

  10. Influence of the local morphology on the surface tension of injection molded polypropylene

    Science.gov (United States)

    Gomes, M.; Pontes, A. J.; Viana, J. C.

    2014-05-01

    In this work, we investigate the development of the morphology of an injection molding polypropylene under the local thermomechanical environment imposed during processing, and its effect on the contact angle and, hence, on the surface tension of the moldings. Melt and mold temperatures were varied in two levels. The local thermomechanical environment was characterized by mold filling computational simulations that allow the calculation of thermomechanical variables (e.g., local temperatures, shear stresses) and indices (related to the local morphology development). In order to investigate the structural hierarchy variations of the moldings in the thickness direction, samples from skin to core were used. The molecular orientation and degree of crystallinity were determined as function of the thickness, as well as the contact angle. The variations of the degree of crystallinity were assessed by differential scanning calorimetry. The level of molecular orientation was evaluated by birefringence measurements. The contact angles were measured in deionized water by sessile drop (needle in) method at room temperature, to determine the wettability of the samples. The contact angles were found to vary along the molding thickness in the skin, transition and core layers. These variations are related to the local morphologies developed. Results suggest that water contact angle increases with the level of molecular orientation and for finer microstructures.

  11. Ion channel recordings on an injection-molded polymer chip

    DEFF Research Database (Denmark)

    Tanzi, Simone; Matteucci, Marco

    2013-01-01

    In this paper, we demonstrate recordings of the ion channel activity across the cell membrane in a biological cell by employing the so-called patch clamping technique on an injection-molded polymer microfluidic device. The findings will allow direct recordings of ion channel activity to be made using the cheapest materials and production platform to date and with the potential for very high throughput. The employment of cornered apertures for cell capture allowed the fabrication of devices without through holes and via a scheme comprising master origination by dry etching in a silicon substrate, electroplating in nickel and injection molding of the final part. The most critical device parameters were identified as the length of the patching capillary and the very low surface roughness on the inside of the capillary. The cross-sectional shape of the orifice was found to be less critical, as both rectangular and semicircular profiles seemed to have almost the same ability to form tight seals with cells with negligible leak currents. The devices were functionally tested using human embryonic kidney cells expressing voltage-gated sodium channels (Nav1.7) and benchmarked against a commercial state-of-the-art system for automated ion channel recordings. These experiments considered current–voltage (IV) relationships for activation and inactivation of the Nav1.7 channels and their sensitivity to a local anesthetic, lidocaine. Both IVs and lidocaine dose–response curves obtained from the injection-molded polymer device were in good agreement with data obtained from the commercial system.

  12. Metal injection molding (MIM) of NdFeB magnets

    OpenAIRE

    Hartwig T.; Lopes L.; Wendhausen P.; Ünal N.

    2014-01-01

    Due to the increased and unstable prices for Rare Earth elements there are activities to develop alternative hard magnetic materials. Reducing the amount of material necessary to produce complex sintered NdFeB magnets can also help to reduce some of the supply problem. Metal Injection Molding (MIM) is able to produce near net shape parts and can reduce the amount of finishing to achieve final geometry. Although MIM of NdFeB has been patented and published fairly soon after the development of ...

  13. Environmental impact estimation of mold making process

    Science.gov (United States)

    Kong, Daeyoung

    Increasing concern of environmental sustainability regarding depletion of natural resources and resulting negative environmental impact has triggered various movements to address these issues. Various regulations about product life cycle have been made and applied to industries. As a result, how to evaluate the environmental impact and how to improve current technologies has become an important issue to product developers. Molds and dies are very generally used manufacturing tools and indispensible parts to the production of many products. However, evaluating environmental impact in mold and die manufacturing is not well understood and not much accepted yet. The objective of this thesis is to provide an effective and straightforward way of environmental analysis for mold and die manufacturing practice. For this, current limitations of existing tools were identified. While conventional life cycle assessment tools provide a lot of life cycle inventories, reliable data is not sufficient for the mold and die manufacturer. Even with comprehensive data input, current LCA tools only provide another comprehensive result which is not directly applicable to problem solving. These issues are critical especially to the mold and die manufacturer with limited resource and time. This thesis addresses the issues based on understanding the needs of mold and die manufacturers. Computer aided manufacturing (CAM) is the most frequently used software tool and includes most manufacturing information including the process definition and sometimes geometric modeling. Another important usage of CAM software tools is problem identification by process simulation. Under the virtual environment, possible problems are detected and solved. Environmental impact can be handled in the same manner. To manufacture molds and dies with minimizing the associated environmental impact, possible environmental impact sources must be minimized before the execution in the virtual environment. Molds and dies are manufacturing intensive products and most of their environmental impact is generated by the energy consumption during the machining processes. Milling and EDM operations were selected as the most influential mold and die manufacturing processes. Process variability was found to be the key issue which must be addressed for reliable analysis. Acceleration and deceleration in the milling process and the dielectric contamination and resultant decrease of MRR in the EDM process were identified as main factors for the variability. Energy consumption of these two processes were analyzed and modeled including the variability. Experiments were carried out to validate and improve this model. Finally, this model is implemented as simulation software tools on the basis of CAM software (Esprit CAM(TM)). The CAM-based tool developed in this study can be more easily used in the mold and die manufacturing practice. Considering the variety of mold and die and their application, this tool would be just a small step to a long way to the environmentally benign mold and die manufacturing. However, with further research, the tool developed in this thesis will result in effective way to address environmentally benign mold and die manufacturing.

  14. A Study on the Sensitivity and Optimization for Gate Location in Injection Mold Filling

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Yeongeun [LG Chemical Ltd., Seoul (Korea, Republic of); Tucker III, Charles L. [Univ. of Illinois at Urbana-Champaign, Illinois (United States)

    2002-11-15

    A manufacturing process design methodology is presented to optimize the gate location in injection molding. The design methodology employs polymer process modeling, design sensitivity analysis, and numerical optimization. To solve the design problem, design sensitivities are used with numerical optimization. A new method to apply inlet boundary condition is presented to locate the gate arbitrarily on the mold and the gate pressure is evaluated from the result pressure field with efficiency. The sensitivities are evaluated with respect to gate locations. During the optimization, a method to measure distance on the curved surface in the unit of element is introduced to keep the gate inside the mold. The method developed in this study is applied to some geometries of application and the optimal location is obtained effectively.

  15. A Study on the Sensitivity and Optimization for Gate Location in Injection Mold Filling

    International Nuclear Information System (INIS)

    A manufacturing process design methodology is presented to optimize the gate location in injection molding. The design methodology employs polymer process modeling, design sensitivity analysis, and numerical optimization. To solve the design problem, design sensitivities are used with numerical optimization. A new method to apply inlet boundary condition is presented to locate the gate arbitrarily on the mold and the gate pressure is evaluated from the result pressure field with efficiency. The sensitivities are evaluated with respect to gate locations. During the optimization, a method to measure distance on the curved surface in the unit of element is introduced to keep the gate inside the mold. The method developed in this study is applied to some geometries of application and the optimal location is obtained effectively

  16. A study of magneto-crystalline alignment in sintered barium hexaferrite fabricated by powder injection molding

    International Nuclear Information System (INIS)

    Barium hexaferrite permanent magnets were produced by powder injection molding. Starting barium hexaferrite powder was prepared from a Fe2O3 and BaCO3 powder mixture by calcination followed by milling. The feedstock for powder injection molding was prepared by mixing barium hexaferrite powder with a low viscosity binder. Magnetic alignment was achieved by applying a high intensity magnetic field to the melted feedstock during the injection process. Green samples (with and without magnetic alignment) were subjected to solvent debinding and subsequent thermal debinding followed by sintering. Sintering conditions were optimized in order to achieve a maximum energy product value. Magneto-crystalline aligning in barium hexaferrite was studied on both green and sintered samples using X-ray diffraction, scanning electron microscope (SEM) and magnetic measurements (hysteresisgraphs). All measurements were made both in a parallel and perpendicular direction to the aligning magnetic field. The obtained results confirmed magneto-crystalline alignment

  17. A study of magneto-crystalline alignment in sintered barium hexaferrite fabricated by powder injection molding

    Science.gov (United States)

    Zlatkov, B. S.; Nikolic, M. V.; Aleksic, O.; Danninger, H.; Halwax, E.

    2009-02-01

    Barium hexaferrite permanent magnets were produced by powder injection molding. Starting barium hexaferrite powder was prepared from a Fe 2O 3 and BaCO 3 powder mixture by calcination followed by milling. The feedstock for powder injection molding was prepared by mixing barium hexaferrite powder with a low viscosity binder. Magnetic alignment was achieved by applying a high intensity magnetic field to the melted feedstock during the injection process. Green samples (with and without magnetic alignment) were subjected to solvent debinding and subsequent thermal debinding followed by sintering. Sintering conditions were optimized in order to achieve a maximum energy product value. Magneto-crystalline aligning in barium hexaferrite was studied on both green and sintered samples using X-ray diffraction, scanning electron microscope (SEM) and magnetic measurements (hysteresisgraphs). All measurements were made both in a parallel and perpendicular direction to the aligning magnetic field. The obtained results confirmed magneto-crystalline alignment.

  18. Correlation between Rheotens measurements and reinforcement of polymer nanocomposites in the injection molding compounder

    Science.gov (United States)

    Battisti, Markus G.; Friesenbichler, Walter; Duretek, Ivica; Guttmann, Peter

    2015-04-01

    The evaluation of the effectiveness of reinforcement of polymers and polymer nanocomposites(PNCs), in particular the improvement of Young's modulus, is made by performing standardized tensile tests. Structural and morphological characterizations typically are investigated using expensive techniques like transmission electron microscopy (TEM), X- ray scattering and sometimes also rheological analyses (rotational rheometry). The objective of this study is to generate faster and economically advantageous data to verify the quality of the produced PNC-compound in an on-line measurement system. Subsequently injection molded parts are processed by using the Injection Molding Compounder (PNC-IMC) “by only one plasticizing process”. In comparison to the conventional compounding process, where the compound has to be pelletized and fed into the injection molding machine for the second plasticizing process, injection molding compounding combines these two processing steps. This paper shows first results and problems with the implementation of the Rheotens equipment into the concept of the IMC. Different processing techniques and various processing conditions were compared and the occurring effects were detected both with tensile testing and extensional melt rheology. Both, the increase of the Young's modulus by using layered silicates as nanofillersis compared to the virgin polypropylene and the correlation of the level of melt strength with Rheotens measurements is shown. These results give a good overview on both the possibilities and the limitations of the material pre-tests by the use of extensional rheology in the concept of the IMC for producing PNCs. Further studies to enable a fast and efficient way of estimating the level of reinforcement in PNCs by means of Rheotens measurements will be carried out towards industrial usability. Furthermore the verification of exfoliation and intercalation of the layered silicates in the polymer matrix using small angle X- ray scattering is planned.

  19. Effect of injection molding parameters on nanofillers dispersion in masterbatch based PP-clay nanocomposites

    Directory of Open Access Journals (Sweden)

    J. Soulestin

    2012-03-01

    Full Text Available The effect of injection molding parameters (screw rotational speed, back pressure, injec-tion flow rate and holding pressure on the nanofiller dispersion of melt-mixed PP/clay nanocomposites was investigated. The nanocomposites containing 4 wt% clay were obtained by dilution of a PP/clay masterbatch into a PP matrix. The evaluation of the dispersion degree was obtained from dynamic rheological measurements. The storage modulus and complex viscosity exhibit significant dependence on the injection molding parameters. PP/clay nanocomposite molded using more severe injection parameters (high shear and long residence time displays the highest storage modulus and complex viscosity, which illustrates the improved dispersion of clay platelets. This better dispersion leads to better mechanical properties particularly higher Young modulus, tensile strength and unnotched impact strength. A Taguchi analysis was used to identify the influence of individual process parameters. The major individual parameter is the injection flow rate, whose increase improves nanoclay dispersion. The combination of high back pressure and high screw rotational speed is also necessary to optimize the dispersion of clay nanoplatelets.

  20. On the Injection Molding of Nanostructured Polymer Surfaces

    DEFF Research Database (Denmark)

    Pranov, Henrik; Rasmussen, Henrik K.

    2006-01-01

    Well-defined nano-topographies were prepared by electron-beam lithography and electroplated to form nickelshims. The surface pattern consisted of square pillars repeated equidistantly within the plane of the surface in a perpendicular arrangement. The width and distance between the squares both ranged from 310 to 3100 rim. All the pillars were 220 nm high. The nickel-shim was used as a surface-template during injection molding of polycarbonate. Secondly, a nickel shim, with a surface pattern consisted of a squared sine with a period of 700 nm and amplitude of 450 nm, was mounted on, and it was in good thermal contact with the upper plate in a hot-press. Polycarbonate/polystyrene was melted on the lower plate while the temperature of the shim was kept below the glass transition temperature. The upper plate was lowered until the shim was in contact with the melt. Experiments were carried out with a clean shim and a shim coated with a monolayer of fluorocarbonsilane. As a result of the surface coating, the amplitude of the replicated grating decreased from about 350 nm in polycarbonate and 100 nm in polystyrene to less than 10 nm. The experiments strongly suggest that the possibility to injection mold sub-micrometer surface structures in polymers mainly relates to adhesive energy between polymer and shim.

  1. Injection molding of nanopatterned surfaces in the sub-micrometer range with induction heating aid

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano; Calaon, Matteo; Tang, Peter Torben; Ravn, Christian

    Replication of sub-micrometer structures by injection molding leads to special requirements for the mold in order to ensure proper replica and acceptable cycle time. This paper investigates the applicability of induction heating embedded into the mold for the improvement of nanopattern replicatio...

  2. Anisotropic injection molding of strontium ferrite powder using a PP/PEG binder system

    Science.gov (United States)

    Lee, S. H.; Jeung, W. Y.

    2001-05-01

    In this study, new binder system for anisotropic injection molding of Sr-ferrite was developed and a process for injection molding of Sr-ferrite was optimized. The developed binder system is composed of 30 vol% PP, 60 vol% PEG-20 000 and 10 vol% PEG-4000. The extraction by water was applied to remove the major binder components PEGs and the minor binder component, PP, was subsequently burned out in air. Behaviors of extraction and thermal debinding with time and debinding atmosphere and variations of the magnetic properties with sintering temperature were studied. The sintered magnets made by PIM process showed residual carbon content of 230 ppm and a maximum energy product of 4.2 MGOe.

  3. Anisotropic injection molding of strontium ferrite powder using a PP/PEG binder system

    International Nuclear Information System (INIS)

    In this study, new binder system for anisotropic injection molding of Sr-ferrite was developed and a process for injection molding of Sr-ferrite was optimized. The developed binder system is composed of 30 vol% PP, 60 vol% PEG-20 000 and 10 vol% PEG-4000. The extraction by water was applied to remove the major binder components PEGs and the minor binder component, PP, was subsequently burned out in air. Behaviors of extraction and thermal debinding with time and debinding atmosphere and variations of the magnetic properties with sintering temperature were studied. The sintered magnets made by PIM process showed residual carbon content of 230 ppm and a maximum energy product of 4.2 MGOe

  4. Mechanical and microstructural investigations of tungsten and doped tungsten materials produced via powder injection molding

    OpenAIRE

    Antusch, S.; Armstrong, D.E.J.; Britton, T. B.; Commin, L.; Gibson, J.S.K.L.; Greuner, H.; Hoffmann, J.; Knabl, W.; Pintsuk, G.; Rieth, M.; Roberts, S. G.; Weingaertner, T.

    2015-01-01

    Abstract The physical properties of tungsten such as the high melting point of 3420°C, the high strength and thermal conductivity, the low thermal expansion and low erosion rate make this material attractive as a plasma facing material. However, the manufacturing of such tungsten parts by mechanical machining such as milling and turning is extremely costly and time intensive because this material is very hard and brittle. Powder Injection Molding (PIM) as special process allows the mass produ...

  5. Analysis of Incomplete Filling Defect for Injection-Molded Air Cleaner Cover Using Moldflow Simulation

    OpenAIRE

    Hyeyoung Shin; Eun-Soo Park

    2013-01-01

    A large-sized cover part for air cleaner was injection molded with ABS resin, and its incomplete filling defect was analyzed using commercial Moldflow software. To investigate the effect of processing temperature on incomplete filling defect, tensile properties, weight loss, and phase separation behavior of ABS resin were evaluated. The tensile properties of dumbbell samples were not changed up to 250°C and decreased significantly thereafter. SEM micrographs indicated no significant changes i...

  6. Injection molding of nanopatterned surfaces in the sub-micrometer range with induction heating aid

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano; Calaon, Matteo; Tang, Peter Torben; Ravn, Christian

    2014-01-01

    Replication of sub-micrometer structures by injection molding leads to special requirements for the mold in order to ensure proper replica and acceptable cycle time. This paper investigates the applicability of induction heating embedded into the mold for the improvement of nanopattern replication. A tool insert having a surface containing functional geometries in the sub-micrometer range was produced using aluminum anodization and nickel electroplating. In order to provide elevated mold tempera...

  7. Dynamic penetration behavior of core-material in multi-cavity co-injection molding

    Science.gov (United States)

    Huang, Chao-Tsai CT; Yang, Jackie; Chang, Rong-Yeu

    2015-12-01

    Co-Injection Molding and multi-cavity molding are very common processes for plastic manufacturing. These two systems are sometimes combined and applied to some structure products. The core penetration and flow balance control problems are very difficult to manage. The inside mechanism of co-injection multi-cavity system is not fully figured out yet. In this study, we have focused on the penetration phenomena of core-material in a co-injection multi-cavity molding. The dynamic penetration behavior of core is very sensitive to injection flow rate and skin/core ratio. The longest core penetration has been shown to change dramatically from one runner to the other. In addition, the core penetration behavior will display imbalance at the end of filling. The more core ratio it is, the longer core penetration flows through runner to cavity. However, due to the multi-cavity geometrical structure, the balance of the core penetration for multi-cavity is still challenging. Finally, the simulation is validated with some literature. The results showed that both simulation and experiment are in a good agreement in trend

  8. Color measurement of plastics - From compounding via pelletizing, up to injection molding and extrusion

    Science.gov (United States)

    Botos, J.; Murail, N.; Heidemeyer, P.; Kretschmer, K.; Ulmer, B.; Zentgraf, T.; Bastian, M.; Hochrein, T.

    2014-05-01

    The typical offline color measurement on injection molded or pressed specimens is a very expensive and time-consuming process. In order to optimize the productivity and quality, it is desirable to measure the color already during the production. Therefore several systems have been developed to monitor the color e.g. on melts, strands, pellets, the extrudate or injection molded part already during the process. Different kinds of inline, online and atline methods with their respective advantages and disadvantages will be compared. The criteria are e.g. the testing time, which ranges from real-time to some minutes, the required calibration procedure, the spectral resolution and the final measuring precision. The latter ranges between 0.05 to 0.5 in the CIE L*a*b* system depending on the particular measurement system. Due to the high temperatures in typical plastics processes thermochromism of polymers and dyes has to be taken into account. This effect can influence the color value in the magnitude of some 10% and is barely understood so far. Different suitable methods to compensate thermochromic effects during compounding or injection molding by using calibration curves or artificial neural networks are presented. Furthermore it is even possible to control the color during extrusion and compounding almost in real-time. The goal is a specific developed software for adjusting the color recipe automatically with the final objective of a closed-loop control.

  9. Injection Molding Parameter Optimization of Titanium Alloy Powder Mix with Palm Stearin and Polyethylene for Multiple Performance Using Grey Relational Analysis

    Directory of Open Access Journals (Sweden)

    K.R. Jamaludin

    2011-01-01

    Full Text Available This paper outlines the optimization the process of injection molding parameters for feedstock of titanium alloy powder and palm stearin binder using grey relational analysis method. A Grey Relational Grade (GRG obtained from the Grey Relational Analysis (GRA is used to solve the injection molding operations with the multiple performance characteristic. The L27 (313 of orthogonal array of Taguchi method were performed. Defects, strength and density are important characteristics in determine the quality of the green part. Using these characteristics, the injection pressure, injection temperature, powder loading, mold temperature, holding pressure and injection speed are optimized in the study. From the analysis of variance (ANOVA, the injection temperature has the highest contribution to the quality of green part followed by injection pressure, powder loading, mold temperature, injection rate and holding pressure.

  10. Imprinted and injection-molded nano-structured optical surfaces

    DEFF Research Database (Denmark)

    Christiansen, Alexander Bruun Technical University of Denmark,

    2013-01-01

    Inspired by nature, nano-textured surfaces have attracted much attention as a method to realize optical surface functionality. The moth-eye antireflective structure and the structural colors of Morpho butterflies are wellknown examples used for inspiration for such biomimetic research. In this paper, nanostructured polymer surfaces suitable for up-scalable polymer replication methods, such as imprinting/embossing and injection-molding, are discussed. The limiting case of injection-moulding compatible designs is investigated. Anti-reflective polymer surfaces are realized by replication of Black Silicon (BSi) random nanostructure surfaces. The optical transmission at normal incidence is measured for wavelengths from 400 nm to 900 nm. For samples with optimized nanostructures, the reflectance is reduced by 50 % compared to samples with planar surfaces. The specular and diffusive reflection of light from polymer surfaces and their implication for creating structural colors is discussed. In the case of injection-moulding compatible designs, the maximum reflection of nano-scale textured surfaces cannot exceed the Fresnel reflection of a corresponding flat polymer surface, which is approx. 4 % for normal incidence. Diffraction gratings provide strong color reflection defined by the diffraction orders. However, the apperance varies strongly with viewing angles. Three different methods to address the strong angular-dependence of diffraction grating based structural color are discussed.

  11. Molds

    Science.gov (United States)

    Molds are fungi that can be found both outdoors and indoors. They grow best in warm, damp and humid conditions. If ... spots in your house, you will probably get mold. Molds can cause health problems. Inhaling or touching ...

  12. Characterization Of Metal Injection Molding (MIM Feedstock Based On Water Soluble Binder System

    Directory of Open Access Journals (Sweden)

    Norhamidi Muhamad

    2008-08-01

    Full Text Available Metal Injection Molding (MIM is a new manufacturing technique especially to produce small and complex precision parts. Characterization of feedstock is one of the important tasks in order to evaluate the homogeneity level of the feedstock prepared and to control the quality of the parts during injection molding process. This paper attempts to investigate the characteristics of the MIM feedstock by performing rheological test using the feedstock consisted of 316L stainless steel powder with a mean particle size of 12 micrometer and a major fraction of water soluble binder system known as polyethylene glycol (PEG. Three different weight percentage of PEG at 65, 75, and 85 respectively were used during the investigation. The viscosity of MIM feedstock at different temperatures and shear rates were measured and evaluated. Results show that increasing the PEG content would decrease the viscosity of the feedstock. The rheological properties of the feedstock showed that the proposed method of mixing is adequate to produce a homogeneous feedstock that is favorable for injection molding process.

  13. Injection molded nanofluidic chips: Fabrication method and functional tests using single-molecule DNA experiments

    DEFF Research Database (Denmark)

    Utko, Pawel; Persson, Karl Fredrik; Kristensen, Anders; Larsen, Niels Bent

    2011-01-01

    We demonstrate that fabrication of nanofluidic systems can be greatly simplified by injection molding of polymers. We functionally test our devices by single-molecule DNA experiments in nanochannels.......We demonstrate that fabrication of nanofluidic systems can be greatly simplified by injection molding of polymers. We functionally test our devices by single-molecule DNA experiments in nanochannels....

  14. Mold design

    International Nuclear Information System (INIS)

    This book introduce the history injection mold, development of plastic industry and production of mold, development property of synthetic resins industry, prospect mold technology, structure and design injection mold with summary for injection mold and mold design for under cut mold goods, design for main part of mold goods design for main part of mold like platen, locate ring, runner and side core pin, sprue, runner and gate, ejector device, plan for strength of mold, faulty of mold like short shot and flow mark, kinds and property of synthetic resins, molder and function and injection terms.

  15. In-mold sensor concept to calculate process-specific rheological properties

    Science.gov (United States)

    Pacher, G. A.; Berger, G. R.; Friesenbichler, W.; Gruber, D. P.; Macher, J.

    2014-05-01

    To gain extended knowledge on the flow behavior of polymer melts during filling phase of the injection molding process, an injection mold featuring complex sensor technology was developed. Three triple-combined FOS MTPS408 cavity sensors (FOS Messtechnik GmbH) are aligned along the flow path of a plate-shaped cavity. Each sensor features an infrared detector, a type K thermocouple, and a piezo-electric pressure detector. This configuration enables the local and transient recording of melt temperature, mold temperature and cavity pressure near gate, part center and end of part simultaneously. Averaged melt velocities are determined by evaluating the differing times of the rising edges of the infrared sensors. Local melt velocities and viscosities are calculated at each sensor position by evaluation of the gradients of temperature and pressure. Moreover, the used injection mold is equipped with RHCM technologies to additionally influence the mold surface temperature and hence the filling of the cavity. The specimens are plate-shaped parts having cut-outs and ribs similar to geometries found in numerous industrial applications such as cover panels. The application of this in-mold sensor concept provides novel possibilities for the systematic in-line analysis and evaluation of process-parameters in injection molding. Further studies will be carried out to connect the process-specific properties to the specimen morphology; aiming at controlling morphology by adjusting process parameters.

  16. Low Cost Injection Mold Creation via Hybrid Additive and Conventional Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Dehoff, Ryan R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Watkins, Thomas R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); List, III, Frederick Alyious [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carver, Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); England, Roger [Cummins, Inc, Knoxville, TN (United States)

    2015-12-01

    The purpose of the proposed project between Cummins and ORNL is to significantly reduce the cost of the tooling (machining and materials) required to create injection molds to make plastic components. Presently, the high cost of this tooling forces the design decision to make cast aluminum parts because Cummins typical production volumes are too low to allow injection molded plastic parts to be cost effective with the amortized cost of the injection molding tooling. In addition to reducing the weight of components, polymer injection molding allows the opportunity for the alternative cooling methods, via nitrogen gas. Nitrogen gas cooling offers an environmentally and economically attractive cooling option, if the mold can be manufactured economically. In this project, a current injection molding design was optimized for cooling using nitrogen gas. The various components of the injection mold tooling were fabricated using the Renishaw powder bed laser additive manufacturing technology. Subsequent machining was performed on the as deposited components to form a working assembly. The injection mold is scheduled to be tested in a projection setting at a commercial vendor selected by Cummins.

  17. Measurements of Powder-Polymer Mixture Properties and Their Use in Powder Injection Molding Simulations for Aluminum Nitride

    Science.gov (United States)

    Kate, Kunal H.; Onbattuvelli, Valmikanathan P.; Enneti, Ravi K.; Lee, Shi W.; Park, Seong-Jin; Atre, Sundar V.

    2012-09-01

    Aluminum nitride has been favored for applications in manufacturing substrates for heat sinks due to its elevated temperature operability, high thermal conductivity, and low thermal expansion coefficient. Powder injection molding is a high-volume manufacturing technique that can translate these useful material properties into complex shapes. In order to design and fabricate components from aluminum nitride, it is important to know the injection-molding behavior at different powder-binder compositions. However, the lack of a materials database for design and simulation at different powder-polymer compositions is a significant barrier. In this paper, a database of rheological and thermal properties for aluminum nitride-polymer mixtures at various volume fractions of powder was compiled from experimental measurements. This database was used to carry out mold-filling simulations to understand the effects of powder content on the process parameters and defect evolution during the injection-molding process. The experimental techniques and simulation tools can be used to design new materials, select component geometry attributes, and optimize process parameters while eliminating expensive and time-consuming trial-and-error practices prevalent in the area of powder injection molding.

  18. Local mechanical properties of LFT injection molded parts: Numerical simulations versus experiments

    Science.gov (United States)

    Desplentere, F.; Soete, K.; Bonte, H.; Debrabandere, E.

    2014-05-01

    In predictive engineering for polymer processes, the proper prediction of material microstructure from known processing conditions and constituent material properties is a critical step forward properly predicting bulk properties in the finished composite. Operating within the context of long-fiber thermoplastics (LFT, length filled compound to compare the measured data with the numerical simulation results. In this investigation, tensile tests and 3 point bending tests are considered. To characterize the fiber length distribution of the polymer melt entering the mold (necessary for the numerical simulations), air shots were performed. For those air shots, similar homogenization conditions were used as during the injection molding tests. The fiber length distribution is characterized using automated optical method on samples for which the matrix material is burned away. Using the appropriate settings for the different experiments, good predictions of the local mechanical properties are obtained.

  19. Development of Defects Free Stainless Steel Parts Using Powder Injection Molding

    Directory of Open Access Journals (Sweden)

    M.A. Omar

    2013-01-01

    Full Text Available Austenitic 316L Stainless Steel (SS is widely used in aerospace, automotive, sports and medical industries due to its mechanical properties and corrosion resistance. Defects free molding of parts depends upon the features of feedstock. In powder injection molding, feedstock preparation is critical step and any deficiency at this stage cannot be retrieve in latter steps. The objective of this research work is to optimize solid loading for defects free injection molded parts. During the present research work five formulations having solid loading 60-71 vol% were prepared by using multi component binder system. The degradation temperature of feedstocks was determined by using Thermogravimetric analysis (TGA and flow behavior through rheometer. Homogeneity of the feedstock was verified by using Scanning Electron Microscopy (SEM. Finally, injection molding was done and it was found that the feedstocks having solid loading up to 69 vol% were successfully injection molded and components were without physical defects.

  20. Modeling of the injection of loaded thermoplastic mixtures with application in metal injection molding

    International Nuclear Information System (INIS)

    The study is focussed on the modeling and numerical simulation of the loaded thermoplastic mixtures currently used in metal injection molding. Due to the fact that the mixture is highly concentrated in metallic powders, the models based on the homogenization theory and using an equivalent viscosity are no longer suitable. So a biphasic formulation has been developed to describe the flow of such mixtures. An interaction term between powder and thermoplastic fluid polymer accounts for segregation or debinding effects. In this type of the problem, the solid phase fraction is a key fields variable. The associated equations are solved separately for each phase taking into account interactions and coupling effects. A general solver in 2D and 3D has been developed that account propagation of fluid front by the extension to biphasic cases of the VOF method. For solving the velocity/pressure problem the fractional step method has been extended to the biphasic cases. Numerical simulations have been compared to the experimental results obtained by a using multiple cavity with pressure and temperature sensors. Comparisons between numerical simulation results and experiments show good agreements in terms of pressure and temperature evolutions during molding. It is also demonstrated that the numerical results are accurate and sensitive to variation of the injection molding marameters. (author)

  1. Optimization of Micro Metal Injection Molding By Using Grey Relational Grade

    International Nuclear Information System (INIS)

    Micro metal injection molding (?MIM) which is a variant of MIM process is a promising method towards near net-shape of metallic micro components of complex geometry. In this paper, ?MIM is applied to produce 316L stainless steel micro components. Due to highly stringent characteristic of ?MIM properties, the study has been emphasized on optimization of process parameter where Taguchi method associated with Grey Relational Analysis (GRA) will be implemented as it represents novel approach towards investigation of multiple performance characteristics. Basic idea of GRA is to find a grey relational grade (GRG) which can be used for the optimization conversion from multi objectives case which are density and strength to a single objective case. After considering the form 'the larger the better', results show that the injection time(D) is the most significant followed by injection pressure(A), holding time(E), mold temperature(C) and injection temperature(B). Analysis of variance (ANOVA) is also employed to strengthen the significant of each parameter involved in this study.

  2. Initial verification of an induction heating set-up for injection molding

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano; Tang, Peter T.; Ravn, Christian

    selected for the investigation is a thin spiral. For the complete molding of the component, elevated mold temperatures are required. For this propose a new injection molding set-up was developed, which allows rapid heating of the cavity wall by an induction heating system. The temperature was measured by...... two thermocouples placed in the die insert. The system was used to heat up the cavity wall with heating rates of up to 10 °C/s. Experiments were carried out with ABS material. The lengths of the object were measured by a suitable measurement set up. The experimental result show that the use of the......Molding of thin and long parts by injection molding leads to special requirements for the mold in order to ensure proper filling and acceptable cycle time. This paper investigates the applicability of embedded induction heating for the improvement of the filling of thin long parts. The object...

  3. Electroforming of Tool Inserts for Injection Molding of Optical or Microfluidic Components

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Christensen, Thomas R.

    2004-01-01

    With a rapidly increasing international interest in “Lab-on-a-chip”-systems as well as affordable polymer optics, the combination of electroforming and injection molding offers an attractive fabrication solution. Miniaturized analysis systems can be used for medical, security (anti terror monitoring) and environmental (waste water monitoring) applications. Optical components in polymer materials can be used for consumer electronics and for sensor systems. The presentation will include the complete fabrication scheme for tool inserts based on machining and electroforming. Electroforming processes for nickel and copper will be disclosed. Processing parameters for the different types of tools as well as quality control measures will be presented.

  4. Numerical prediction of fiber orientation in injection-molded short-fiber/thermoplastic composite parts with experimental validation

    International Nuclear Information System (INIS)

    Numerical prediction of the fiber orientation in the short-glass fiber (GF) reinforced polyamide 6 (PA6) composites with the fiber weight concentration of 30%, 50%, and 70% manufactured by the injection molding process is presented. And the fiber orientation was also directly observed and measured through X-ray computed tomography. During the injection molding process of the short-fiber/thermoplastic composite, the fiber orientation is produced by the flow states and the fiber-fiber interaction. Folgar and Tucker equation is the well known for modeling the fiber orientation in a concentrated suspension. They included into Jeffrey’s equation a diffusive type of term by introducing a phenomenological coefficient to account for the fiber-fiber interaction. Our developed model for the fiber-fiber interaction was proposed by modifying the rotary diffusion term of the Folgar-Tucker equation. This model was presented in a conference paper of the 29th International Conference of the Polymer Processing Society published by AIP conference proceeding. For modeling fiber interaction, the fiber dynamic simulation was introduced in order to obtain a global fiber interaction coefficient, which is sum function of the fiber concentration, aspect ratio, and angular velocity. The fiber orientation is predicted by using the proposed fiber interaction model incorporated into a computer aided engineering simulation package C-Mold. An experimental program has been carried out in which the fiber orientation distribution has been measured in 100 x 100 x 2 mm injection-molded plate and 100 x 80 x 2 mm injection-molded weld by analyzed with a high resolution 3D X-ray computed tomography system XVA-160?, and calculated by X-ray computed tomography imaging. The numerical prediction shows a good agreement with experimental validation. And the complex fiber orientation in the injection-molded weld was investigated

  5. Numerical prediction of fiber orientation in injection-molded short-fiber/thermoplastic composite parts with experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Thi, Thanh Binh Nguyen; Morioka, Mizuki; Yokoyama, Atsushi [Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Hamanaka, Senji; Yamashita, Katsuhisa; Nonomura, Chisato [Research Center, Toyobo Co., LTD, 2-1-1 Katata, Otsu, Shiga 520-0292 (Japan)

    2015-05-22

    Numerical prediction of the fiber orientation in the short-glass fiber (GF) reinforced polyamide 6 (PA6) composites with the fiber weight concentration of 30%, 50%, and 70% manufactured by the injection molding process is presented. And the fiber orientation was also directly observed and measured through X-ray computed tomography. During the injection molding process of the short-fiber/thermoplastic composite, the fiber orientation is produced by the flow states and the fiber-fiber interaction. Folgar and Tucker equation is the well known for modeling the fiber orientation in a concentrated suspension. They included into Jeffrey’s equation a diffusive type of term by introducing a phenomenological coefficient to account for the fiber-fiber interaction. Our developed model for the fiber-fiber interaction was proposed by modifying the rotary diffusion term of the Folgar-Tucker equation. This model was presented in a conference paper of the 29{sup th} International Conference of the Polymer Processing Society published by AIP conference proceeding. For modeling fiber interaction, the fiber dynamic simulation was introduced in order to obtain a global fiber interaction coefficient, which is sum function of the fiber concentration, aspect ratio, and angular velocity. The fiber orientation is predicted by using the proposed fiber interaction model incorporated into a computer aided engineering simulation package C-Mold. An experimental program has been carried out in which the fiber orientation distribution has been measured in 100 x 100 x 2 mm injection-molded plate and 100 x 80 x 2 mm injection-molded weld by analyzed with a high resolution 3D X-ray computed tomography system XVA-160?, and calculated by X-ray computed tomography imaging. The numerical prediction shows a good agreement with experimental validation. And the complex fiber orientation in the injection-molded weld was investigated.

  6. Numerical prediction of fiber orientation in injection-molded short-fiber/thermoplastic composite parts with experimental validation

    Science.gov (United States)

    Thi, Thanh Binh Nguyen; Morioka, Mizuki; Yokoyama, Atsushi; Hamanaka, Senji; Yamashita, Katsuhisa; Nonomura, Chisato

    2015-05-01

    Numerical prediction of the fiber orientation in the short-glass fiber (GF) reinforced polyamide 6 (PA6) composites with the fiber weight concentration of 30%, 50%, and 70% manufactured by the injection molding process is presented. And the fiber orientation was also directly observed and measured through X-ray computed tomography. During the injection molding process of the short-fiber/thermoplastic composite, the fiber orientation is produced by the flow states and the fiber-fiber interaction. Folgar and Tucker equation is the well known for modeling the fiber orientation in a concentrated suspension. They included into Jeffrey's equation a diffusive type of term by introducing a phenomenological coefficient to account for the fiber-fiber interaction. Our developed model for the fiber-fiber interaction was proposed by modifying the rotary diffusion term of the Folgar-Tucker equation. This model was presented in a conference paper of the 29th International Conference of the Polymer Processing Society published by AIP conference proceeding. For modeling fiber interaction, the fiber dynamic simulation was introduced in order to obtain a global fiber interaction coefficient, which is sum function of the fiber concentration, aspect ratio, and angular velocity. The fiber orientation is predicted by using the proposed fiber interaction model incorporated into a computer aided engineering simulation package C-Mold. An experimental program has been carried out in which the fiber orientation distribution has been measured in 100 x 100 x 2 mm injection-molded plate and 100 x 80 x 2 mm injection-molded weld by analyzed with a high resolution 3D X-ray computed tomography system XVA-160?, and calculated by X-ray computed tomography imaging. The numerical prediction shows a good agreement with experimental validation. And the complex fiber orientation in the injection-molded weld was investigated.

  7. Reaction injection molding and direct covalent bonding of OSTE+ polymer microfluidic devices

    Science.gov (United States)

    Sandström, N.; Shafagh, R. Z.; Vastesson, A.; Carlborg, C. F.; van der Wijngaart, W.; Haraldsson, T.

    2015-07-01

    In this article, we present OSTE+RIM, a novel reaction injection molding (RIM) process that combines the merits of off-stoichiometric thiol-ene epoxy (OSTE+) thermosetting polymers with the fabrication of high quality microstructured parts. The process relies on the dual polymerization reactions of OSTE+ polymers, where the first curing step is used in OSTE+RIM for molding intermediately polymerized parts with well-defined shapes and reactive surface chemistries. In the facile back-end processing, the replicated parts are directly and covalently bonded and become fully polymerized using the second curing step, generating complete microfluidic devices. To achieve unprecedented rapid processing, high replication fidelity and low residual stress, OSTE+RIM uniquely incorporates temperature stabilization and shrinkage compensation of the OSTE+ polymerization during molding. Two different OSTE+ formulations were characterized and used for the OSTE+RIM fabrication of optically transparent, warp-free and natively hydrophilic microscopy glass slide format microfluidic demonstrator devices, featuring a storage modulus of 2.3 GPa and tolerating pressures of at least 4 bars.

  8. Simulação do processo de injeção de polipropileno isotático (iPP) utilizando um modelo de cinética de cristalização quiescente / Simulation of injection molding process of isotactic polypropylene (iPP) using a quiescent crystallization kinetics model

    Scientific Electronic Library Online (English)

    Marcos A, d' Ávila; Carlos H, Ahrens; Rosario E. S, Bretas.

    1997-12-01

    Full Text Available Este trabalho concentrou-se na simulação das fases de preenchimento e resfriamento do processo de injeção do polipropileno isotático. Foi utilizado um modelo matemático baseado nas equações de conservação onde foi considerada a cinética de cristalização quiescente como termo fonte na equação da ener [...] gia. Os parâmetros do modelo de cinética de cristalização, assim como os do modelo de viscosidade, foram obtidos experimentalmente. Para a solução das equações governantes foi utilizado o método dos volumes finitos. Como resultados foram obtidos os campos de temperatura, pressão, velocidade, taxa de cisalhamento e cristalinidade em diferentes condições de processamento. Abstract in english This work is concerned with the simulation of the filling and cooling stages of the injection molding process of an isotactic polypropylene (iPP). A mathematical model based on the conservation equations was used. A crystallization kinetics model was considered as a source term in the energy equatio [...] n. The parameters of the crystallization kinetics model, as well as the viscosity model, were obtained by experimental techniques. For the solution of the governing equations the finite volume method was employed. Temperature, pressure, velocity, shear rate and crystalinity profiles under different processing conditions were obtained.

  9. Properties of high density polyethylene – Paulownia wood flour composites via injection molding

    Science.gov (United States)

    Paulownia wood (PW) flour is evaluated as a bio-based fiber reinforcement. Composites of high density polyethylene (HDPE), 25% by weight of PW, and either 0% or 5% by weight of maleated polyethylene (MAPE) were produced by twin screw compounding followed by injection molding. Molded test composite...

  10. Stability of FDTS monolayer coating on aluminum injection molding tools

    DEFF Research Database (Denmark)

    Cech, Jiri; Taboryski, Rafael J.

    2012-01-01

    tools has reduced lead time (days instead of weeks) and manufacturing cost (30% of conventional mold). Moreover, for aluminum, a surface roughness (RMS) below 5 nm can be obtained with diamond machining [3,4,6]. Conventional mold coatings add cost and complexity, and coatings with thicknesses of a few...

  11. Cytocompatibility of titanium metal injection molding with various anodic oxidation post-treatments

    International Nuclear Information System (INIS)

    Metal injection molding (MIM) is a near net shape manufacturing method that allows for the production of components of small to moderate size and complex shape. MIM is a cost-effective and flexible manufacturing technique that provides a large innovative potential over existing methods for the industry of implantable devices. Commercially pure titanium (CP-Ti) samples were machined to the same shape as a composite feedstock with titanium and polyoxymethylene, and these metals were injected, debinded and sintered to assess comparative biological properties. Moreover, we treated MIM-Ti parts with BIOCOAT®, BIODIZE® and BIOCER®, three different anodic oxidation techniques that treat titanium using acid, alkaline and anion enriched electrolytes, respectively. Cytocompatibility as well as morphological and chemical features of surfaces was comparatively assessed on each sample, and the results revealed that MIM-Ti compared to CP-Ti demonstrated a specific surface topography with a higher roughness. MIM-Ti and BIOCER® samples significantly enhanced cell proliferation, cell adhesion and cell differentiation compared to CP-Ti. Interestingly, in the anodization post-treatment established in this study, we demonstrated the ability to improve osseointegration through anionic modification treatment. The excellent biological response we observed with MIM parts using the injection molding process represents a promising manufacturing method for the future implantable devices in direct contact with bones. - Highlights: ? Metal injection molding technique gives titanium a specific surface roughness. It enhances the biological response. ? Anodic oxidation method adds Ca, P, and Mg ions on the surface, promoting the cell adhesion. ? Cytocompatibility analyses show an increased cell adhesion and proliferation on MIM-Ti compared to pure titanium.

  12. Cytocompatibility of titanium metal injection molding with various anodic oxidation post-treatments

    Energy Technology Data Exchange (ETDEWEB)

    Demangel, Clemence; Auzene, Delphine [CRITT-MDTS, ZHT du Moulin Leblanc, 3, Bd Jean Delautre 08000 Charleville-Mezieres (France); Vayssade, Muriel [Universite de Technologie de Compiegne, UMR 7338 Biomecanique-Bioingenierie, BP 20529 60205 Compiegne Cedex (France); Duval, Jean-Luc, E-mail: jean-luc.duval@utc.fr [Universite de Technologie de Compiegne, UMR 7338 Biomecanique-Bioingenierie, BP 20529 60205 Compiegne Cedex (France); Vigneron, Pascale; Nagel, Marie-Daniele [Universite de Technologie de Compiegne, UMR 7338 Biomecanique-Bioingenierie, BP 20529 60205 Compiegne Cedex (France); Puippe, Jean-Claude [Steiger Galvanotechnique, Route de Pra de Plan, 18 CH-1618 Chatel-St-Denis (Switzerland)

    2012-10-01

    Metal injection molding (MIM) is a near net shape manufacturing method that allows for the production of components of small to moderate size and complex shape. MIM is a cost-effective and flexible manufacturing technique that provides a large innovative potential over existing methods for the industry of implantable devices. Commercially pure titanium (CP-Ti) samples were machined to the same shape as a composite feedstock with titanium and polyoxymethylene, and these metals were injected, debinded and sintered to assess comparative biological properties. Moreover, we treated MIM-Ti parts with BIOCOAT Registered-Sign , BIODIZE Registered-Sign and BIOCER Registered-Sign , three different anodic oxidation techniques that treat titanium using acid, alkaline and anion enriched electrolytes, respectively. Cytocompatibility as well as morphological and chemical features of surfaces was comparatively assessed on each sample, and the results revealed that MIM-Ti compared to CP-Ti demonstrated a specific surface topography with a higher roughness. MIM-Ti and BIOCER Registered-Sign samples significantly enhanced cell proliferation, cell adhesion and cell differentiation compared to CP-Ti. Interestingly, in the anodization post-treatment established in this study, we demonstrated the ability to improve osseointegration through anionic modification treatment. The excellent biological response we observed with MIM parts using the injection molding process represents a promising manufacturing method for the future implantable devices in direct contact with bones. - Highlights: Black-Right-Pointing-Pointer Metal injection molding technique gives titanium a specific surface roughness. It enhances the biological response. Black-Right-Pointing-Pointer Anodic oxidation method adds Ca, P, and Mg ions on the surface, promoting the cell adhesion. Black-Right-Pointing-Pointer Cytocompatibility analyses show an increased cell adhesion and proliferation on MIM-Ti compared to pure titanium.

  13. Structural and magnetic properties of sintered Sr-ferrites fabricated by powder injection molding

    Science.gov (United States)

    Murillo, N.; González, J.; Guraya, C.; Gutiérrez, M.; Seco, F. J.

    1999-08-01

    Studies of microstructure (SEM and metalographic micrographs) and magnetic properties (remanent magnetisation and coercive field) have been performed on bipolar sintered Sr-ferrite permanent magnets obtained by powder injection molding (PIM) method under applied magnetic field in order to align the magnetic particles during the PIM process. Magnetic measurements on the samples were made in the parallel and perpendicular direction of the aligning magnetic field. The remanence in the direction of alignment increased sharply with the alignment field to a maximum value of 3840 Gs while the coercivity decreases to a minimum value of 3220 Oe.

  14. Short-term and long-term behavior of PP-polymer nanocomposites produced by injection molding compounding

    Science.gov (United States)

    Battisti, M. G.; Guttmann, P.; Chitu, L.; Friesenbichler, W.

    2015-05-01

    There are only few investigations considering the impact of nanoscale fillers on the mechanical und thermo-mechanical properties of polymers. Particularly there is a lack of results regarding long term creep behavior of Polypropylene-based polymer nanocomposites (PNCs). Therefore, the objective of this study is to determine the influence of nanofiller content on the mechanical and thermo-mechanical behavior of Polypropylene-based PNCs. Processing of the test specimens was carried out using the Polymer NanoComposite Injection Molding Compounder (PNC-IMC). In comparison to the conventional compounding process, in which the compound must be pelletized and fed into the injection molding machine for the second plasticizing process, injection molding compounding combines these two processing steps. Material compounding and subsequent injection molding are done directly with only one plasticizing process, using a heated melt pipe and a melt accumulator for melt transfer from the compounder to the injection molding machine. The PNCs were produced in the 3-in-1 process at the PNC-IMC, where all components (polymer, compatibilizer, nanofiller) were added simultaneously into the compounder. Furthermore, the polymer melt was treated using elongational flow generating devices for better intercalation and exfoliation of the nanofillers. Tensile tests were made to characterize the short-term-mechanical properties. Tensile creep tests show the influence of nanofillers on the long-term-creep-performance and dynamic mechanical tests (DMA) were performed to investigate the thermo-mechanical behavior. Both, the improvements in the mechanical and thermo-mechanical properties in comparison to the pure polypropylene are shown and give an excellent overview of possibilities and limitations of the PNCs. Further research will focus on the detailed understanding of the different mechanisms of property improvement of layered silicates in polymer. By using small angle X-ray scattering exfoliation and intercalation of the layered silicates in the polymer matrix will be verified.

  15. Single Performance Optimization of Micro Metal Injection Molding for the Highest Green Strength by Using Taguchi Method

    OpenAIRE

    M.H.I Ibrahim; N. Muhamad; A.B Sulong; K.R. Jamaludin; S. Ahmad; N.H. M. Nor

    2010-01-01

    Micro metal injection molding is drawing attention recently as one the most cost effective processes in powder metallurgy to produce small-scale intricate part and competitive cost for mass production of micro components where it is greatly influenced by injection parameter. Thus, this paper investigated the optimization of highest green strength which plays an important characteristic in determining the successful of micro MIM. Stainless steel SS 316L was used with composite binder, which co...

  16. Injection molding of nickel based 625 superalloy: Sintering, heat treatment, microstructure and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Oezguen, Oezguer [Bingol University, Technical Sciences Vocational School, 12000 Bingol (Turkey); Sakarya University, Graduate School of Applied and Natural Sciences, 54187 Sakarya (Turkey); Oezkan Guelsoy, H., E-mail: ogulsoy@marmara.edu.tr [Marmara University, Technology Faculty, Metallurgy and Materials Eng. Dep., 34722 Istanbul (Turkey); Yilmaz, Ramazan [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey); Findik, Fehim [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey); International University of Sarajevo, Faculty of Engineering and Natural Sciences, Department of Mechanical Engineering, 71000 Sarajevo, Bosnia and Herzegovina (Bosnia and Herzegowina)

    2013-01-05

    Highlights: Black-Right-Pointing-Pointer Sintering, microstructural and mechanical properties of injection molded nickel based 625 superalloy were studied. Black-Right-Pointing-Pointer The maximum sintered density achieved this study was 98.3% at 1300 Degree-Sign C for 3 h. Black-Right-Pointing-Pointer Tensile strength of 674 MPa, elongation of 40.6% and hardness of 303 HV were achieved for sintered and heat treated conditions. - Abstract: This study concerns determination of optimum sintering and thermal process parameters for Ni-based alloy 625 superalloy formed by the method of powder injection molding (PIM). Samples, formed from the feedstock by mixing the prealloyed 625 powder with a multi-component binding system, are made subject to sintering at different temperatures following the debinding process. Samples that are sintered under such conditions giving way to the highest relative density (3 h at 1300 Degree-Sign C), are aged after they have been subject to solution treated thermal process. Sintered, solution treated and aged samples have been subjected to microstructural analysis and mechanical test. Mechanical tests such as hardness measurement and tensile test as well as microstructural characterization such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and elemental analysis all have shown that the aging thermal process increases strength of the material. However, it is observed that alloy 625 produced by the method of PIM is at such level to compete with the characteristics of cast alloy 625.

  17. Numerical modeling of magnetic induction and heating in injection molding tools

    DEFF Research Database (Denmark)

    Guerrier, Patrick; Hattel, Jesper Henri

    2013-01-01

    Injection molding of parts with special requirements or features such as micro- or nanostructures on the surface, a good surface finish, or long and thin features results in the need of a specialized technique to ensure proper filling and acceptable cycle time. The aim of this study is to increase the temperatures as close as possible to the cavity surface, by means of an integrated induction heating system in the injection molding tool, to improve the fluidity of the polymer melt hereby ensuring that the polymer melt will continue to flow until the mold cavity is completely filled. The presented work uses numerical modeling of the induction heating in the mold to investigate how the temperature in the mold will be distributed and how it is affected by different material properties.

  18. Temperature Dependence and Magnetic Properties of Injection Molding Tool Materials Used in Induction Heating

    DEFF Research Database (Denmark)

    Guerrier, Patrick; Nielsen, Kaspar Kirstein; Hattel, Jesper Henri

    2015-01-01

    this paper, been characterized for their temperature-dependent magnetic properties. The properties have been measured using a vibrating sample magnetometer, able to reach to 350 °C. The established material database comprises the B–H loops, from which the mean B–H curve, relative permeability versus......To analyze the heating phase of an induction heated injection molding tool precisely, the temperature-dependent magnetic properties, B–H curves, and the hysteresis loss are necessary for the molding tool materials. Hence, injection molding tool steels, core materials among other materials have, in...

  19. Temperature Dependence and Magnetic Properties of Injection Molding Tool Materials Used in Induction Heating

    DEFF Research Database (Denmark)

    Guerrier, Patrick; Nielsen, Kaspar Kirstein

    2015-01-01

    To analyze the heating phase of an induction heated injection molding tool precisely, the temperature-dependent magnetic properties, B–H curves, and the hysteresis loss are necessary for the molding tool materials. Hence, injection molding tool steels, core materials among other materials have, in this paper, been characterized for their temperature-dependent magnetic properties. The properties have been measured using a vibrating sample magnetometer, able to reach to 350 °C. The established material database comprises the B–H loops, from which the mean B–H curve, relative permeability versus magnetic flux density, and hysteresis loss versus magnetic flux density have been extracted and are presented.

  20. Transcription of Small Surface Structures in Injection Molding - an Experimental Study

    DEFF Research Database (Denmark)

    ArlØ, Uffe Rolf; Kjær, Erik Michael

    2001-01-01

    The ability to replicate the surface roughness from mold wall to the plastic part in injection moldning has many functional and cosmetic important implications from medical use to designer products. Generally the understanding of surface transcription i.e the the replication of the surface structure from the mould to plastic part, also relates to micro injection moulding and moulding of parts with specific micro structures on the surface such as optical parts. The present study concerns transcription of surface roughness as a function of process parameters. The study is carried out with a polystyrene part, process parameters at typical levels and a rough spark eroded mould surface with Ra=12.6 micro meters.

  1. Measuring mechanical stresses on inserts during injection molding

    OpenAIRE

    Heinle, Martina; Drummer, Dietmar

    2015-01-01

    ssembly molding presents an interesting approach to innovative product solutions. Here, individual components can be simultaneously positioned, affixed, and provided with a casing. However, while overmolding elements in the mold cavity with hot polymer melt, high mechanical loads occur on, in some cases, very sensitive components such as electronic devices. For the design of such systems, it is important to know these stresses, the influences on their quantities, and mathematical options for ...

  2. Optimization of injection molded parts by using ANN-PSO approach

    Directory of Open Access Journals (Sweden)

    R. Spina

    2006-02-01

    Full Text Available Purpose: The aim of the work was the optimization of injection molded product warpage by using an integrated environment.Design/methodology/approach: The approach implemented took advantages of the Finite Element (FE Analysis to simulate component fabrication and investigate the main causes of defects. A FE model was initially designed and then reinforced by integrating Artificial Neural Network to predict main filling and packing results and Particle Swarm Approach to optimize injection molding process parameters automatically.Findings: This research has confirmed that the evaluation of the FE simulation results through the Artificial Neural Network system was an efficient method for the assessment of the influence of process parameter variation on part manufacturability, suggesting possible adjustments to improve part quality.Research limitations/implications: Future researches will be addressed to the extension of analysis to large thin components and different classes of materials with the aim to improve the proposed approach.Originality/value: The originality of the work was related to the possibility of analyzing component fabrication at the design stage and use results in the manufacturing stage. In this way, design, fabrication and process control were strictly links.

  3. MECHANICAL PROPERTIES OF INJECTION-MOLDED FOAMED WHEAT STRAW FILLED HDPE BIOCOMPOSITES: THE EFFECTS OF FILLER LOADING AND COUPLING AGENT CONTENTS

    OpenAIRE

    Fatih Mengeloglu; Kadir Karaku?

    2012-01-01

    This study investigated the effect of filler loading and coupling agent contents on the densities and mechanical properties of injection-molded foamed biocomposites. Biocomposite pellets were manufactured using wheat straw flour, maleic anhydrite grafted polyethylene (MAPE), paraffin wax, and high-density polyethylene (HDPE) with an extrusion process. Pellets and the chemical foaming agent (azodicarbonamide) were dry-mixed and foamed in an injection-molding machine. Densities and mechanical p...

  4. Enteric-coating of pulsatile-release HPC capsules prepared by injection molding.

    Science.gov (United States)

    Macchi, E; Zema, L; Maroni, A; Gazzaniga, A; Felton, L A

    2015-04-01

    Capsular devices based on hydroxypropyl cellulose (Klucel® LF) intended for pulsatile release were prepared by injection molding (IM). In the present work, the possibility of exploiting such capsules for the development of colonic delivery systems based on a time-dependent approach was evaluated. For this purpose, it was necessary to demonstrate the ability of molded cores to undergo a coating process and that coated systems yield the desired performance (gastric resistance). Although no information was available on the coating of IM substrates, some issues relevant to that of commercially-available capsules are known. Thus, preliminary studies were conducted on molded disks for screening purposes prior to the spray-coating of HPC capsular cores with Eudragit® L 30 D 55. The ability of the polymeric suspension to wet the substrate, spread, start penetrating and initiate hydration/swelling, as well as to provide a gastroresistant barrier was demonstrated. The coating of prototype HPC capsules was carried out successfully, leading to coated systems with good technological properties and able to withstand the acidic medium with no need for sealing at the cap/body joint. Such systems maintained the original pulsatile release performance after dissolution of the enteric film in pH 6.8 fluid. Therefore, they appeared potentially suitable for the development of a colon delivery platform based on a time-dependent approach. PMID:25585355

  5. Influence of the polypropylene structure on the replication of nanostructures by injection molding

    Science.gov (United States)

    Vera, Julie; Brulez, Anne-Catherine; Contraires, Elise; Larochette, Mathieu; Valette, Stéphane; Benayoun, Stéphane

    2015-11-01

    In this paper, an experimental study of replication by injection molding of sub-micrometer features is presented. Two polypropylenes with different melt flow rates (MFR) were used throughout this study. The used removable mold insert was textured with a femtosecond laser. Replication of these periodic structures, called ripples, is thus investigated. Despite different MFR, we show that the viscosities of the two polymers at the investigated temperatures and injection shear rates are similar. The reproducibility of the injected molded samples and the texture of the mold were analyzed. We propose a specific methodology to quantify the reproducibility quality replicas. The latter introduces morphological parameters such as anisotropy rate, power density, etc. A difference between the two replicas was noticeable. Based on rheological analysis, the viscosity was ruled out as the origin of this difference. Other properties were identified as the source such as the chain length and the stress relaxation time. Their impact on the replication quality was investigated and found interesting.

  6. Reducción del Tiempo de Ciclo de Inyección de Termoplásticos con el uso de Moldes con Tratamiento Superficial por Nitruración / Cycle Time Reduction of Thermoplastic Injection using Nitriding Treatment Surface Molds

    Scientific Electronic Library Online (English)

    Emerson J, Corazza; Carlos M, Sacchelli; Cintia, Marangoni.

    Full Text Available Se presenta un estudio sobre la transferencia de calor en un molde, comparando los ensayos de inyección utilizando moldes con y sin tratamiento superficial de nitruración. Simulaciones del proceso se realizaron con el uso de Asistencia Computacional a Ingeniería (CAE) para determinar los parámetros [...] iniciales que se aplicaron en los ensayos reales en moldes instrumentados de acero P20 (con y sin tratamientos), inyectados con el polímero poliestireno cristal. Los resultados indicaron una reducción del tiempo de enfriamiento y del tiempo de proceso en el molde con el tratamiento, debido a una mejora en la conductividad térmica. Abstract in english A study on the heat transfer in a mold, comparing experimental injection tests using a mold with and without surface treatment (nitriding) is presented. Process simulations were carried out using Computer Aided Engineering tools (CAE) for the estimation of the initial parameters to be applied in the [...] tests in instrumented P20 steel injection molds with the polymer crystal polystyrene. Results indicated a reduction of cooling time and of the time of the process in the mold with treatment, due to an increase of the thermal conductivity.

  7. Efeito do processamento em misturas de alumina/ligantes orgânicos usadas na moldagem por injeção em baixa pressão / Effect of processing variables in alumina/organic binders mixtures used in low-pressure injection molding

    Scientific Electronic Library Online (English)

    P . A., Ourique; A., Susin Neto; S. G., Echeverrigaray; R. C. D., Cruz; J. E., Zorzi.

    2013-03-01

    Full Text Available A moldagem por injeção em baixa pressão (MIBP) é uma técnica que já vem sendo empregada na produção de peças cerâmicas com formas e geometrias complexas. A homogeneidade da mistura de ligantes orgânicos e pós cerâmicos é um fator determinante que deve ser controlado para minimizar a formação de impe [...] rfeições no processamento de feedstocks para MIBP. Defeitos típicos de processamento por MIBP, como bolhas de ar e aglomerados, geram gradientes de densidade nas misturas que, após conformação, possuem poucas possibilidades de remoção. Essas imperfeições comprometem o desempenho dos produtos obtidos por essa técnica. Este trabalho está focado na avaliação dessas heterogeneidades e como elas podem ser correlacionadas com a variação da densidade aparente e com o comportamento reológico dessas misturas. Para tanto, aluminas submicrométricas, como recebida e desaglomerada, foram adicionadas a uma mistura fundida de ligantes a base de parafinas, ceras e aditivos e processada em dois tipos diferentes de misturadores, com e sem o auxílio de vácuo. Foi observada a presença de aglomerados existentes na alumina como recebida, possivelmente gerados durante a etapa de calcinação. Também foi observado que o tipo de misturador e a aplicação ou não de vácuo durante a etapa final do processamento têm grande influência no tempo de mistura necessário para reduzir a viscosidade do feedstock para a injeção. Abstract in english The low-pressure injection molding (LPIM) is a technique already being used in the production of ceramic parts with complex shapes and geometries. The homogeneity of the mixture of organic binder and ceramic powder is a determining factor which must be controlled to minimize defects formation while [...] feedstock processing to LPIM. Typical defects of LPIM processing, such as air bubbles and agglomerates, generate density gradients in the mixtures, which, after shaping, have little possibility of removal. These imperfections compromise the performance of the products obtained by this technique. This work is focused on the evaluation of these inhomogeneities and how they can be correlated with density variation and the rheological behavior of these mixtures. Therefore, submicrometer aluminas, as received and deagglomerated, were added to a molten mixture of paraffin based binders, waxes and additives and processed in two different mixers, with and without vacuum. The presence of alumina agglomerates was observed in the powder as received, possibly generated during the calcination step. It was also observed that the type of mixer and vacuum application or not during the final processing step, has a major influence on the mixing time required to reduce the viscosity of the feedstock for injection.

  8. Efeito do processamento em misturas de alumina/ligantes orgânicos usadas na moldagem por injeção em baixa pressão Effect of processing variables in alumina/organic binders mixtures used in low-pressure injection molding

    Directory of Open Access Journals (Sweden)

    P . A. Ourique

    2013-03-01

    Full Text Available A moldagem por injeção em baixa pressão (MIBP é uma técnica que já vem sendo empregada na produção de peças cerâmicas com formas e geometrias complexas. A homogeneidade da mistura de ligantes orgânicos e pós cerâmicos é um fator determinante que deve ser controlado para minimizar a formação de imperfeições no processamento de feedstocks para MIBP. Defeitos típicos de processamento por MIBP, como bolhas de ar e aglomerados, geram gradientes de densidade nas misturas que, após conformação, possuem poucas possibilidades de remoção. Essas imperfeições comprometem o desempenho dos produtos obtidos por essa técnica. Este trabalho está focado na avaliação dessas heterogeneidades e como elas podem ser correlacionadas com a variação da densidade aparente e com o comportamento reológico dessas misturas. Para tanto, aluminas submicrométricas, como recebida e desaglomerada, foram adicionadas a uma mistura fundida de ligantes a base de parafinas, ceras e aditivos e processada em dois tipos diferentes de misturadores, com e sem o auxílio de vácuo. Foi observada a presença de aglomerados existentes na alumina como recebida, possivelmente gerados durante a etapa de calcinação. Também foi observado que o tipo de misturador e a aplicação ou não de vácuo durante a etapa final do processamento têm grande influência no tempo de mistura necessário para reduzir a viscosidade do feedstock para a injeção.The low-pressure injection molding (LPIM is a technique already being used in the production of ceramic parts with complex shapes and geometries. The homogeneity of the mixture of organic binder and ceramic powder is a determining factor which must be controlled to minimize defects formation while feedstock processing to LPIM. Typical defects of LPIM processing, such as air bubbles and agglomerates, generate density gradients in the mixtures, which, after shaping, have little possibility of removal. These imperfections compromise the performance of the products obtained by this technique. This work is focused on the evaluation of these inhomogeneities and how they can be correlated with density variation and the rheological behavior of these mixtures. Therefore, submicrometer aluminas, as received and deagglomerated, were added to a molten mixture of paraffin based binders, waxes and additives and processed in two different mixers, with and without vacuum. The presence of alumina agglomerates was observed in the powder as received, possibly generated during the calcination step. It was also observed that the type of mixer and vacuum application or not during the final processing step, has a major influence on the mixing time required to reduce the viscosity of the feedstock for injection.

  9. Crystallization kinetics and morphology of PBT/MMT and PTT/MMT nanocomposites during injection molding

    International Nuclear Information System (INIS)

    This work had as main objective to study the crystallization of nanocomposites of poly(butylene terephthalate) (PBT) and poly(trimethylene terephthalate) (PTT) with a montmorillonite nanoclay (MMT) using an on-line optical monitoring system during the injection molding and to characterize the morphologies of the injection samples by polarized light optical microscopy (PLOM), wide angle X-ray diffraction (WAXS) and differential scanning calorimetry (DSC). The optical system allowed to analyze the crystallization process by the changes of the optical properties during the solidification of the materials. It was concluded that the MMT lamellae accelerated the overall crystallization of the polymers. By PLOM, it was observed that the nanoclay caused qualitative changes on the morphology of the PTT (polymer with slow crystallization kinetics). The crystallinity indexes were not affected by the addition of the MMT; however, by WAXS it was shown that the nanocomposites had a higher orientation degree. (author)

  10. Effect of injection molded micro-structured polystyrene surfaces on proliferation of MC3T3-E1 cells

    Directory of Open Access Journals (Sweden)

    G. Lucchetta

    2015-04-01

    Full Text Available In this work, osteoinductive micro-pillared polystyrene surfaces were mass-produced for bone replacement applications, by means of the micro injection molding process. Firstly, the molding process parameters were optimized with a two-level, three-factor central composite face-centered plan to increase the quality of polystyrene micro pillars replication and to maximize the pillars height uniformity over the molded part. Secondly, osteoblastic MC3T3-E1 cells adhesion and proliferation on the replicated substrates were assessed as a function of micro topography parameters, such as pillars diameter, aspect ratio and spacing. Cell morphology and proliferation were evaluated through MTS test after 1, 3 and 7 days from seeding. The experimental results showed that cells adhesion and proliferation is more positively promoted on micro-pillared surfaces compared to flat surfaces, but no correlations were observed between cell proliferation and pillar diameter and spacing.

  11. Bulk and Surface Molecular Orientation Distribution in Injection-molded Liquid Crystalline Polymers: Experiment and Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Fang, J.; Burghardt, W; Bubeck, R; Burgard, S; Fischer, D

    2010-01-01

    Bulk and surface distributions of molecular orientation in injection-molded plaques of thermotropic liquid crystalline polymers (TLCPs) have been studied using a combination of techniques, coordinated with process simulations using the Larson-Doi 'polydomain' model. Wide-angle X-ray scattering was used to map out the bulk orientation distribution. Fourier Transform Infrared Attenuated Total Reflectance (FTIR-ATR) and Near-Edge X-ray Absorption Fine Structure (NEXAFS) were utilized to probe the molecular orientation states to within about {approx}5 {micro}m and {approx}2 nm, respectively, of the sample surface. These noninvasive, surface-sensitive techniques yield reasonable self-consistency, providing complementary validation of the robustness of these methods. An analogy between Larson-Doi and fiber orientation models has allowed the first simulations of TLCP injection molding. The simulations capture many fine details in the bulk orientation distribution across the sample plaque. Direct simulation of surface orientation at the level probed by FTIR-ATR and NEXAFS was not possible due to the limited spatial resolution of the simulations. However, simulation results extracted from the shear-dominant skin region are found to provide a qualitatively accurate indicator of surface orientation. Finally, simulations capture the relation between bulk and surface orientation states across the different regions of the sample plaque.

  12. Microcellular injection molding and particulate leaching of thermoplastic polyurethane (TPU) scaffolds

    Science.gov (United States)

    Mi, Hao-Yang; Jing, Xin; Turng, Lih-Sheng; Peng, Xiang-Fang

    2014-05-01

    Microcellular injection moldingand particulate leaching methods were combined to fabricate porousand interconnectedthermoplastic polyurethane (TPU) tissue engineering scaffolds. Water soluble polyvinyl alcohol (PVOH) and sodium chloride (NaCl) were used as porogens to improve the porosity and interconnectivity, as well as the hydrophilicity, of the scaffolds. The effect of each factor-namely, PVOH, NaCl, and microcellular injection molding-on scaffold morphology was investigated. It was found that the microcellular injection molding processwas effectiveatproducing high pore density and porosity. The addition of PVOH decreasedthe pore diameter and increasedthe pore density. Furthermore, scaffolds with NaCl and PVOH porogens hadbetter interconnectivity. The residual PVOH improved the hydrophilicity of the scaffold.

  13. Comparison of two setups for induction heating in injection molding

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans Nørgaard; Bissacco, Giuliano; Guerrier, Patrick; Tang, Peter Torben

    based on a test geometry integrating different aspect ratios of small structures. Acrylonitrile butadiene styrene (ABS) was used as material, and different mold temperatures were tested. The replicated test objects were measured by means of an optical coordinate measuring machine (CMM). On the basis of...

  14. Mechanical properties of the weld line defect in micro injection molding for various nano filled polypropylene composites

    International Nuclear Information System (INIS)

    Research highlights: ? PP/CNFs and PP/TiO2 composites with relative high loading fractions (10, 20, 30 and 35 wt%) were fabricated by inner melt mixing process. Micro tensile test samples were formed by injection molding combined with variotherm process for all composites. ? The morphological properties of all nano composites were characterized by WXRD, whose results imply the adding nano fillers did not change the crystal form of PP, but the crystallites size and distance between lattices of crystals were changed with various nano fillers and loading fractions. ? DSC analysis show that due to the nucleating function of nano fillers, the peak temperature of crystallization was increased and the peak temperature of crystallization melting was decreased by adding the nanofillers. ? The flow ability of nano composites was tested by high pressure single capillary rheometer and the results demonstrate that nano fillers increased the viscosity of PP matrix. ? Based on these significant information and analysis foundation of the nano filled composites, the micro weld line samples were formed by injection molding process and characterized by tensile test method. From the achieved results, it can be found that in general, for functional nano filled polymer composites, the mechanical property of micro weld lines were obviously influenced by nano fillers' shape and loading fractions. ? The E modulus of micro weld line was increased due to loading CNFs in PP matrix, while the elongation of the micro tensile samples with weld line is considerably decreased comparing with those of unfilled PP samples. The detrimental tensile strength of micro weld lines were observed when CNFs contents increasing, except for at a 10 wt%. ? For TiO2 nano particles filled PP, due to the poor dispersion of nano particles, at low loading fraction of 10 wt%, the E modulus and tensile strength of micro weld lines were decreased by filling nano particles, but when the loading fraction is increased to 30%, the E modulus and tensile strength of micro weld line were increased again compared with the low loading level. ? Finally, an empirical prediction equation for micro injection molded weld line strength of nano PP composites was proposed for higher nano filler loading fraction than 10 wt%. - Abstract: The nano filled functional polymer materials have been widely processed with micro injection molding technology for micro electromechanical systems (MEMS) fabrication. As the unfavorable defect in micro injection molding parts, weld line brings reduced mechanical and physical properties, especially for nano filled composites. In this study, polypropylene (PP) was compounded respectively with carbon nano fibers (CNFs) and TiO2 nano particles at various weight fractions (10, 20, 30, 35 wt%) through co-screws internal mixing. The morphological, thermal and rheological properties of nano composites were characterized by wider angle X-ray diffraction (WXRD), different scanning calorimeter (DSC) and high pressure capillary rheometer. Additionally, under the constant setting of injection molding process parameters in injection molding machine, micro tensile samples with weld lines for each nano filled PP composite were produced. The tensile tests were served as the characterizing method for weld line mechanical properties. The results show that when the CNFs is filled higher than 10 wt%, the tensile strength of samples with weld lines made of nano composites become lower than neat PP. While the raising CNFs content contributes to the improved E modulus of micro injection molded weld lines. Additionally, with the increasing fraction of CNFs in PP, the weld line area's elongation percent is decreased. Whereas for case of TiO2, the 10 wt% is the threshold for micro injection molded weld line tensile strength turning from decrease trend to increase. The same as CNFs, elongation of micro weld line samples were in general lower than neat PP as well, due to the addition of TiO2 nano particles.

  15. Micro Injection Molding of Thin Walled Geometries with Induction Heating System

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans NØrgaard

    2014-01-01

    To eliminate defects and improve the quality of molded parts, increasing the mold temperature is one of the applicable solutions. A high mold temperature can increase the path flow of the polymer inside the cavity allowing reduction of the number of injection points, reduction of part thickness and moulding of smaller and more complex geometries. The last two aspects are very important in micro injection molding. In this paper a new embedded induction heating system is proposed and validated. An experimental investigation was performed based on a test geometry integrating different aspect ratios of small structures. ABS was used as material and different combinations of injection velocity, pressure and mold temperature were tested. The replicated test objects were measured by means of an optical CMM machine. On the basis of the experimental investigation the efficacy of the embedded induction heating system with respect to improvement of replication quality, reduction of injection pressure and injection velocity as well as reduction of cycle time has been verified.

  16. Injection molded polymer chip for electrochemical and electrophysiological recordings from single cells

    DEFF Research Database (Denmark)

    Tanzi, Simone; Larsen, Simon Tylsgaard; Taboryski, Rafael J.

    2011-01-01

    We present a novel method to fabricate an all in polymer injection molded chip for electrochemical cell recordings and lateral cell trapping. The complete device is molded in thermoplastic polymer and it results from assembling two halves. We tested spin-coated conductive polymer poly(3,4-ethylenedioxythiopene) and showed that it can be used as an electrode material for detecting neurotransmitters electrochemically in biosensors.

  17. Uni- and biaxial impact behavior of double-gated nanoclay-reinforced polypropylene injection moldings

    OpenAIRE

    Pettarin, Valeria; Viau, Gastón; Fasce, L.; J.C. Viana; A. J. Pontes; Frontini, P. M.; Pouzada, A. S.

    2013-01-01

    Polypopylene/nanoclay three-dimensional parts were produced without intermediate steps by direct injection molding to explore the influence of flow features and nanoclay incorporation in their impact performance. The nanocomposite was obtained by direct compounding of commercial PP with nanoclay masterbatch. The as-molded morphology was analyzed by X-ray and TEM analyses in terms of skin-core structure and nanoclay particle dispersion. The nanoclay particles induced...

  18. Mold

    Centers for Disease Control (CDC) Podcasts

    2011-05-02

    This podcast answers a listener's question about the risks associated with mold after a natural disaster or severe weather.  Created: 5/2/2011 by National Center for Environmental Health (NCEH).   Date Released: 5/2/2011.

  19. Mold

    Science.gov (United States)

    ... that indoor exposure to certain molds, such as Alternaria alternata , is a risk factor for asthma. 10 ... RD, London SJ, Zeldin DC. 2006. Exposure to Alternaria alternata in US homes is associated with asthma ...

  20. Effect of mold rotation on the bifilar electroslag remelting process

    Science.gov (United States)

    Shi, Xiao-fang; Chang, Li-zhong; Wang, Jian-jun

    2015-10-01

    A novel electroslag furnace with a rotating mold was fabricated, and the effects of mold rotational speed on the electroslag remelting process were investigated. The results showed that the chemical element distribution in ingots became uniform and that their compact density increased when the mold rotational speed was increased from 0 to 28 r/min. These results were attributed to a reasonable mold speed, which resulted in a uniform temperature in the slag pool and scattered the metal droplets randomly in the metal pool. However, an excessive rotational speed caused deterioration of the solidification structure. When the mold rotational speeds was increased from 0 to 28 r/min, the size of Al2O3 inclusions in the electroslag ingot decreased from 4.4 to 1.9 ?m. But the excessive mold rotational speed would decrease the ability of the electroslag remelting to remove the inclusions. The remelting speed gradually increased, which resulted in reduced power consumption with increasing mold rotational speed. This effect was attributed to accelerated heat exchange between the consumable electrode and the molten slag, which resulted from mold rotation. Nevertheless, when the rotational speed reached 28 r/min, the remelting speed did not change because of limitations of metal heat conduction. Mold rotation also improved the surface quality of the ingots by promoting a uniform temperature distribution in the slag pool.

  1. Aplikasi Rekayasa Mutu untuk Mengurangi Cacat pada Mesin Injection Molding

    Directory of Open Access Journals (Sweden)

    Glenn Eko Yulianto

    1999-01-01

    Full Text Available The imperfect combustion process will be a problem in the development effort of diesel engine's performance. Nonhomogen air-fuel mixing process is one of the factors which cause the imperfect combustion. By heating up the diesel fuel up to a certain temperature before it goes through the high pressure injection pump will lower its density and viscosity. Therefore, when injected in the combustion chamber, it will formed smaller droplets of fuel spray which result in a more homogenious air-fuel mixture. Also by using higher temperature will make the diesel fuel easier to ignite in order to compensate the limited time which is available in high speed operating conditions. Diesel fuel heating can improve the combustion process to increase the power and decrease the fuel consumption optimally. Abstract in Bahasa Indonesia : Tidak sempurnanya proses pembakaran merupakan masalah yang akan dijumpai dalam usaha peningkatan kinerja motor diesel. Proses pencampuran udara dan bahan bakar yang kurang baik menjadi salah satu faktor penyebab ketidak sempurnaan tersebut. Dengan melakukan pemanasan terhadap solar sampai temperatur tertentu sebelum masuk ke dalam pompa tekanan tinggi akan menyebabkan penurunan density dan viskositas solar, sehingga bila diinjeksikan ke dalam ruang bakar akan membentuk butiran kabut bahan bakar yang lebih halus yang akan menyebabkan proses pencampuran bahan bakar dan udara menjadi lebih homogen. Disamping itu, dengan temperatur yang lebih tinggi akan membuat solar menjadi lebih mudah terbakar sehingga dapat mengimbangi singkatnya waktu yang tersedia untuk pembakaran pada putaran tinggi. Pemanasan solar dapat dipergunakan sebagai salah satu cara untuk menyempurnakan proses pembakaran sehingga dihasilkan peningkatan daya dan penurunan konsumsi bahan bakar yang optimal. Kata kunci : peningkatan daya, penurunan konsumsi bahan bakar, motor diesel, proses pembakaran

  2. INVESTIGATION OF THE INFLUENCE OF MOLD ROTATIONAL SPEED ON THE CAST WALL THICKNESS IN THE ROTATIONAL MOLDING PROCESS

    Directory of Open Access Journals (Sweden)

    Tomasz Jachowicz

    2013-09-01

    Full Text Available This paper presents the rotational molding process. The general principles of this polymer processing technology have been described. The main applications have been introduced and leading advantages and typical disadvantages of rotational molding process have been discussed. Based on the conducted experimental tests, the influence of changing one selected technological parameter, which characterized rotational molding process, on selected geometrical features of the polymer cast has been determined. Rotational mold’s speed around axes was changed and a thickness of cast walls has been measured. Laboratory test stand, processing properties of polymer, also test program and experimental test methodology have been described.

  3. Injection molding of ultra-fine Si3N4 powder for gas-pressure sintering

    Science.gov (United States)

    Yang, Xian-feng; Yang, Jiang-hong; Xu, Xie-wen; Liu, Qi-cheng; Xie, Zhi-peng; Liu, Wei

    2015-06-01

    The ceramic injection molding technique was used in the gas-pressure sintering of ultra-fine Si3N4 powder. The feedstock's flowability, debinding rate, defect evolution, and microstructural evolution during production were explored. The results show that the solid volume loading of less than 50vol% and the surfactant mass fraction of 6wt% result in a perfect flowability of feedstock; this feedstock is suitable for injection molding. When the debinding time is 8 h at 40°C, approximately 50% of the wax can be solvent debinded. Defects detected during the preparation are traced to improper injection parameters, mold design, debinding parameters, residual stress, or inhomogeneous composition distribution in the green body. The bulk density, Vickers hardness, and fracture toughness of the gas-pressure-sintered Si3N4 ceramic reach 3.2 g/cm3, 16.5 GPa, and 7.2 MPa·m1/2, respectively.

  4. A wide variety of injection molding technologies is now applicable to small series and mass production

    Energy Technology Data Exchange (ETDEWEB)

    Bloß, P., E-mail: bloss@kuz-leipzig.de, E-mail: juettner@kuz-leipzig.de, E-mail: jacob@kuz-leipzig.de, E-mail: loeser@kuz-leipzig.de, E-mail: michaelis@kuz-leipzig.de, E-mail: krajewsky@kuz-leipzig.de; Jüttner, G., E-mail: bloss@kuz-leipzig.de, E-mail: juettner@kuz-leipzig.de, E-mail: jacob@kuz-leipzig.de, E-mail: loeser@kuz-leipzig.de, E-mail: michaelis@kuz-leipzig.de, E-mail: krajewsky@kuz-leipzig.de; Jacob, S., E-mail: bloss@kuz-leipzig.de, E-mail: juettner@kuz-leipzig.de, E-mail: jacob@kuz-leipzig.de, E-mail: loeser@kuz-leipzig.de, E-mail: michaelis@kuz-leipzig.de, E-mail: krajewsky@kuz-leipzig.de; Löser, C., E-mail: bloss@kuz-leipzig.de, E-mail: juettner@kuz-leipzig.de, E-mail: jacob@kuz-leipzig.de, E-mail: loeser@kuz-leipzig.de, E-mail: michaelis@kuz-leipzig.de, E-mail: krajewsky@kuz-leipzig.de; Michaelis, J., E-mail: bloss@kuz-leipzig.de, E-mail: juettner@kuz-leipzig.de, E-mail: jacob@kuz-leipzig.de, E-mail: loeser@kuz-leipzig.de, E-mail: michaelis@kuz-leipzig.de, E-mail: krajewsky@kuz-leipzig.de; Krajewsky, P., E-mail: bloss@kuz-leipzig.de, E-mail: juettner@kuz-leipzig.de, E-mail: jacob@kuz-leipzig.de, E-mail: loeser@kuz-leipzig.de, E-mail: michaelis@kuz-leipzig.de, E-mail: krajewsky@kuz-leipzig.de [Kunststoff-Zentrum in Leipzig gGmbH (KuZ), Leipzig (Germany)

    2014-05-15

    Micro plastic parts open new fields for application, e. g., to electronics, sensor technologies, optics, and medical engineering. Before micro parts can go to mass production, there is a strong need of having the possibility for testing different designs and materials including material combinations. Hence, flexible individual technical and technological solutions for processing are necessary. To manufacture high quality micro parts, a micro injection moulding machine named formicaPlast based on a two-step plunger injection technology was developed. Resulting from its design, the residence time and the accuracy problems for managing small shot volumes with reproducible high accuracy are uncompromisingly solved. Due to their simple geometry possessing smooth transitions and non adherent inner surfaces, the plunger units allow to process 'all' thermoplastics from polyolefines to high performance polymers, optical clear polymers, thermally sensitive bioresorbables, highly filled systems (the so-called powder injection molding PIM), and liquid silicon rubber (LSR, here with a special kit). The applied platform strategy in the 1K and 2K version allows integrating automation for assembling, handling and packaging. A perpendicular arrangement allows encapsulation of inserts, also partially, and integration of this machine into process chains. Considering a wide variety of different parts consisting of different materials, the high potential of the technology is demonstrated. Based on challenging industrial parts from electronic applications (2K micro MID and bump mat, where both are highly structured parts), the technological solutions are presented in more detail.

  5. A wide variety of injection molding technologies is now applicable to small series and mass production

    International Nuclear Information System (INIS)

    Micro plastic parts open new fields for application, e. g., to electronics, sensor technologies, optics, and medical engineering. Before micro parts can go to mass production, there is a strong need of having the possibility for testing different designs and materials including material combinations. Hence, flexible individual technical and technological solutions for processing are necessary. To manufacture high quality micro parts, a micro injection moulding machine named formicaPlast based on a two-step plunger injection technology was developed. Resulting from its design, the residence time and the accuracy problems for managing small shot volumes with reproducible high accuracy are uncompromisingly solved. Due to their simple geometry possessing smooth transitions and non adherent inner surfaces, the plunger units allow to process 'all' thermoplastics from polyolefines to high performance polymers, optical clear polymers, thermally sensitive bioresorbables, highly filled systems (the so-called powder injection molding PIM), and liquid silicon rubber (LSR, here with a special kit). The applied platform strategy in the 1K and 2K version allows integrating automation for assembling, handling and packaging. A perpendicular arrangement allows encapsulation of inserts, also partially, and integration of this machine into process chains. Considering a wide variety of different parts consisting of different materials, the high potential of the technology is demonstrated. Based on challenging industrial parts from electronic applications (2K micro MID and bump mat, where both are highly structured parts), the technological solutions are presented in more detail

  6. Rapid mold temperature variation for assisting the micro injection of high aspect ratio micro-feature parts using induction heating technology

    Science.gov (United States)

    Chen, Shia-Chung; Jong, Wen-Ren; Chang, Yaw-Jen; Chang, Jen-An; Cin, Jin-Chuan

    2006-09-01

    Hot embossing and injection molding are popular methods to duplicate micro features formed during polymer micro-fabrication of MEMS devices. However, both methods face challenges in filling the polymer melt completely into a micro-featured geometry of a high aspect ratio. In this study, electromagnetic induction heating combined with water cooling is used to achieve rapid mold surface temperature control during the micro-feature injection molding process. A CAE simulation was also developed through integration of both thermal and electromagnetic analysis modules of ANSYS, and its capability and accuracy were verified experimentally. Efficiency evaluations of induction heating and the uniformity of mold temperature control were conducted on a micro-featured mold. This mold was designed with a micro channel array of 30-50 µm in width and 120 and 600 µm in depth, corresponding to aspect ratios ranging from about 2.4 to 12. The accuracies of the micro channels in molded PMMA parts can be used to evaluate the effect of mold temperature on replication accuracy. It was found that rapid mold surface heating with temperature rising from 60 °C to between 100 °C and 140 °C by induction heating requires 2-3.5 s, while the mold temperature returns to 60 °C in about 70-110 s. The simulated mold surface temperature results are consistent with measured results. Achieving the same temperature variation by switching circulation coolants of different temperatures requires at least 7 min. The simulation also reveals that the electromagnetic wave can penetrate into the bottom of the micro channel and results in only about a 2 °C difference in temperature uniformity. For mold temperatures of 100 °C, 120 °C and 140 °C, the molded channel depths were 94.9 µm, 105.4 µm and 116.0 µm, respectively, when the ideal channel depth was 120 µm. When the channel depth is 600 µm, the mold temperature must exceed 120 °C, so that reasonable accuracy in micro-feature replication can be achieved. Our results to date indicate that the aspect ratio for molded PMMA micro channels can be as high as 12. Efficient mold temperature variation by induction heating to improve the replication accuracy in molding micro features is successfully illustrated.

  7. Acoustic Emission Detection of Macro-Cracks on Engraving Tool Steel Inserts during the Injection Molding Cycle Using PZT Sensors

    Directory of Open Access Journals (Sweden)

    Aleš Han?i?

    2013-05-01

    Full Text Available This paper presents an improved monitoring system for the failure detection of engraving tool steel inserts during the injection molding cycle. This system uses acoustic emission PZT sensors mounted through acoustic waveguides on the engraving insert. We were thus able to clearly distinguish the defect through measured AE signals. Two engraving tool steel inserts were tested during the production of standard test specimens, each under the same processing conditions. By closely comparing the captured AE signals on both engraving inserts during the filling and packing stages, we were able to detect the presence of macro-cracks on one engraving insert. Gabor wavelet analysis was used for closer examination of the captured AE signals’ peak amplitudes during the filling and packing stages. The obtained results revealed that such a system could be used successfully as an improved tool for monitoring the integrity of an injection molding process.

  8. High quality ion channels recordings on an injection molded polymer chip

    DEFF Research Database (Denmark)

    Tanzi, Simone

    2013-01-01

    In this thesis we demonstrate high quality recordings of the ion channel activity across the cell membrane in a biological cell by employing the so called patch clamping technique on an injection molded polymer microfluidic device. Such recordings are traditionally made using glass micropipettes, or in recent years using consumable microfluidic chips of high costs. The patch clamping method is widely used both in fundamental studies of electrophysiology of living cells and tissue and in drug discovery. The findings of this work will allow direct recordings of ion channel activity to be made using the cheapest materials and production platform to date, and with the potential for very high throughput. The employment of cornered apertures for cell capture allowed the fabrication of devices without through holes via a process comprising master origination by dry etching in a silicon substrate, electroplating in nickel, and injection molding of the final part. A thorough characterization of the patching orifices by means of SEM and AFM showed high replication accuracy through the fabrication process. The most critical device parameters were identified as the length of the patching capillaries and the very low surface roughness inside of the capillaries. The cross-sectional shape of the cornered apertures was found to be less critical, as apertures with different profiles were tested with cells and showed the same ability to form tight seals with cells with negligible leak currents. The ability to form high resistance seals in the GOhm range, the so called gigaseals, is demonstrated with a success rate of 15%. The devices were functionally tested with Human Embryonice Kidney (HEK) cells expressing voltage-gated sodium channels and benchmarked against a commercial state-of-the-art system for automated ion channel recordings. These experiments considered current-voltage relationships for activation and inactivation of the sodium channels and their sensitivity to a local anesthetic, lidocaine. Both IVs and lidocaine does response curves obtained from the injection molded polymer device were in excellent agreement with data obtained from the commercial system.

  9. An easy-to-decompose binder for Ti metal injection molding: Preparation and characterization of feedstock

    Science.gov (United States)

    Hayat, Muhammad Dilawer; Wen, Guian; Cao, Peng

    2015-03-01

    Impurity control is crucial to Ti metal powder injection molding (Ti-MIM) since titanium is a universal solvent to interstitial elements such as oxygen, carbon and nitrogen. In this study, a low decomposition temperature binder system was developed; the rheological and solvent debinding assessments of the feedstock formulated from this binder were performed. Solvent mixing was employed to prepare homogeneous feedstocks. Effects of powder shape and solid loading on rheological properties were evaluated. After injection molding, a debinding profile was constructed. The debound parts were then characterized by microstructural observation.

  10. Mejora de la etapa de llenado en moldes de inyección de plástico usando vibración / Improvement Performance of the Filling Step in Injection Mold through Vibration

    Scientific Electronic Library Online (English)

    J.P., Benítez-Rangel; L.A., Morales-Hernández; M., Trejo-Hernández.

    2012-12-01

    Full Text Available El presente trabajo muestra la mejora de flujo que tiene la etapa de llenado del proceso de inyección de plásticos, debida a la excitación del polímero a través de vibración. Dicho proceso, puede resumirse en tres etapas principales que son: el llenado, el empaquetado y el enfriamiento. El proceso d [...] e llenado es el paso en el que se pueden cambiar una gran cantidad de propiedades, tanto mecánicas como estéticas del producto terminado. El objetivo de esta investigación es mostrar que el llenado del molde mejora adicionando vibración, sin tener que agregar aditivos químicos. Para ello, se llevó a cabo el diseño y fabricación de un molde experimental, en el cual se acondicionó un mecanismo de vibración que permitió demostrar las ventajas de la vibración en dicho proceso. Además, se propuso una metodología heurística para la elaboración de las pruebas que reveló una mejora en el llenado con frecuencias cercanas a los 3 Hz. Abstract in english This paper shows the flow improvement in the filling step of the polymer injection process due to the polymer excitation though vibration. This process can be split up into three main steps: filling, pocking and cooling. Several mechanical and aesthetic properties of the finished product can be chan [...] ged in the filling step. The objective of this investigation is to demonstrate the improvement in the filling mold under vibration without adding chemical products. To reach this result, an experimental mold was designed and manufactured in which a vibration device was coupled; it was possible to demonstrate the vibration advantage through this process. Moreover, a heuristic methodology was proposed for the experiment which shows an improvement in the filling process with frequencies close to 3 Hz.

  11. Localized rapid heating process for precision chalcogenide glass molding

    Science.gov (United States)

    Li, Hui; He, Peng; Yu, Jianfeng; Lee, L. James; Yi, Allen Y.

    2015-10-01

    Precision glass molding is an important process for high volume optical fabrication. However, conventional glass molding is a bulk heating process that usually requires a long thermal cycle, where molding assembly and other mechanical parts are heated and cooled together. This often causes low efficiency and other heating and cooling related problems, such as large thermal expansion in both the molds and molded optics. To cope with this issue, we developed a localized rapid heating process to effectively heat only very small part of the glass. This localized rapid heating study utilized a fused silica wafer coated with a thin graphene layer to heat only the surface of the glass. The graphene coating functions as an electrical resistant heater when a power source was applied across the thin film coating, generating heat on and near the coating. The feasibility of this process was validated by both experiments and numerical simulation. To demonstrate the advantages of the localized rapid heating, both localized rapid heating process and bulk heating process were performed and carefully compared. The uniformity and quality of the molded sample by localized rapid heating process was also demonstrated. In summary, localized rapid heating process by using graphene coated fused silica wafer was characterized and can be readily implemented in replication of micro scale chalcogenide glasses. A fused silica wafer coated with a thin graphene layer was utilized for localized rapid heating only the surface of the glass. The graphene coating functions as an electrical resistant heater when a power source was applied across the thin film coating, generating high temperature on and near the coating. This process is fast and efficient since only interested areas are heated without affecting the entire glass substrate or the mold assembly. The uniformity and quality of the molded sample by localized rapid heating process was demonstrated by comparing both localized rapid heating process and conventional bulk heating process.

  12. Fabrication and characterization of injection molded multi level nano and microfluidic systems

    DEFF Research Database (Denmark)

    Matteucci, Marco; Christiansen, Thomas Lehrmann

    2013-01-01

    We here present a method for fabrication of multi-level all-polymer chips by means of silicon dry etching, electroplating and injection molding. This method was used for successful fabrication of microfluidic chips for applications in the fields of electrochemistry, cell trapping and DNA elongation. These chips incorporate channel depths in the range between 100nm and 100?m and depth to width aspect ratios between 1/200 and 2. Optimization of the sealing process of all-polymer COC microfluidic chips by means of thermal bonding is also presented. The latter includes comparing the bonding strength of UV-treated foils and presentation of a simple model for estimating the delamination pressure. With UV surface treatments, foils of 100?m thickness were found to withstand pressures up to 9atm in Ø4mm cylindrical inlets when thermally bonded to micropatterned substrates of 2mm thickness.

  13. Hot mold casting process of ancient East India and Bangladesh

    Directory of Open Access Journals (Sweden)

    Barnali Mandal

    2010-05-01

    Full Text Available Ancient casting process for production of brass or bronze utensils and icons were made in hot molds using clay molded investment casting or piece mold process, as presumed by archaeologists. Piece mold process is still traditionally practiced in many parts of Eastern India and Bangladesh along with investment casting process. Incidentally, Bengal artisans are more accustomed to piece mold process unlike tribal artisans who practiced investment casting process. This piece mold casting process has been reconstructed to get the idea of metal characteristics in order to investigate ancient casting process of Bengal and Bangladesh. The characterization of ancient archaeo-metal products come to a type of cast Cu-Sn-Zn-Pb type quaternary alloy produced by a slow freezing process. Though these alloys physically differ from the traditional cast alloy of binary Cu-Zn type brass, the physical characteristics are similar to the binary cast alloy character. This investigation throws light on the similarity of the production processes by which ancient artisans probably produced cast metal products.

  14. Chemical vapor deposition and analysis of thermally insulating ZrO2 layers on injection molds

    International Nuclear Information System (INIS)

    High quality injection molding requires a precise control of cooling rates. Thermal barrier coating (TBC) of zirconia with a thickness of 20-40 ?m on polished stainless steel molds could provide the necessary insulating effect. This paper presents results of zirconia deposition on stainless steel substrates using chemical vapor deposition (CVD) aiming to provide the process parameters for the deposition of uniform zirconia films with such a thickness. The deposition was performed with zirconium (IV) acetylacetonate (Zr(C5H7O2)4) as precursor and synthetic air as co-reactant, which allows deposition at temperatures below 600 C. The experiments were carried out in a hot-wall reactor at pressures between 7.5 mbar and 500 mbar and in a temperature range from 450 C to 600 C. Important growth parameters were characterized and growth rates between 1 and 2.5 ?m/h were achieved. Thick and well adhering zirconia layers of 38 ?m could be produced on steel within 40 h. The transient heat transfer rate upon contact with a hot surface was also evaluated experimentally with the thickest coatings. These exhibit a good TBC performance. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. A Novel Injection-Molded Capsular Device for Oral Pulsatile Delivery Based on Swellable/Erodible Polymers

    OpenAIRE

    Gazzaniga, Andrea; Cerea, Matteo; COZZI, ALBERTO; Foppoli, Anastasia; Maroni, Alessandra; Zema, Lucia

    2011-01-01

    The feasibility of injection molding was explored in the preparation of a novel capsular device for oral pulsatile/delayed delivery based on swellable/erodible polymers. For this purpose, a mold intended to be coupled with a bench-top injection-molding press was designed. This was expected to enable the preparation of matching capsule cap and body items within a single manufacturing cycle and the selection of differing shell thicknesses (300, 600, and 900 ?m). Hydroxypropylcellulose (Klucel® ...

  16. All-in-polymer injection molded device for single cell capture using multilevel silicon master fabrication

    DEFF Research Database (Denmark)

    Tanzi, S.; Larsen, S.T.

    2012-01-01

    This work demonstrates a novel all-in-polymer device for single cell capture applicable for biological recordings. The chip is injection molded and comprises a "cornered" (non planar) aperture. It has been demonstrated how cornered apertures are straightforward to mold in PDMS [1,2]. In this study we demonstrate cornered apertures made in a thermoplastic polymer. One of the advantages of cornered apertures is the ease of microscopy under a standard inverted optical microscope, when using transparent materials. After the part is injection molded, the sealing of the chip is performed by thermal bonding to a polymer foil, so the complete device results from only two parts. It differs from similar devices in the novel material and fabrication platform that enables high reproducibility and inexpensive mass production. Optimization of the fabrication scheme has been carried out in order to avoid defects during demolding. Capturing of single PC12 cells has been demonstrated.

  17. Solving depressions formed during production of plastic molding

    Directory of Open Access Journals (Sweden)

    J. Dobránsky

    2015-07-01

    Full Text Available This article deals with improvement of design properties of molded plastic parts. It can be achieved by modifying construction of metal injection mold and optimization of parameters in injection process. The subject of our examination was depressions formed on molded plastic parts which are inacceptable in the process of approval. The problem which has arisen was solved in two phases. The first phase consisted in alteration of injection mold design – enlargement of injection molding gate. In the second phase, we have changed the location of injection molding gate. After performing constructional modifications, new molded plastic parts were manufactured and assessed.

  18. THERMAL PROPERTIES OF EXTRUDED-INJECTION MOLDED POLY (LACTIC ACID) AND FIBER BLENDS

    Science.gov (United States)

    In order to determine the degree of compatibility between PLA and different bio-materials (fibers), PLA was blended with sugar beet pulp, apple, cuphea, lasquerella, and milkweed fibers. Fibers were added at 85:15 and 70:30 PLA:Fiber. The composites were dry blended, extruded and injection molded....

  19. Thermal properties of extruded/injection-molded poly(lactic acid) and biobased composites

    Science.gov (United States)

    In order to determine the degree of compatibility between PLA and different biomaterials (fibers), PLA was compounded with sugar beet pulp and apple fibers. Fibers were added at 85:15 and 70:30 PLA:Fiber. The composites were blended by extrusion followed by injection molding. Differential Scannin...

  20. All-in-polymer injection molded device for single cell capture using multilevel silicon master fabrication

    DEFF Research Database (Denmark)

    Tanzi, S.; Larsen, S.T.; Matteucci, M.; Taboryski, R.

    we demonstrate cornered apertures made in a thermoplastic polymer. One of the advantages of cornered apertures is the ease of microscopy under a standard inverted optical microscope, when using transparent materials. After the part is injection molded, the sealing of the chip is performed by thermal...

  1. Processes at the inetrface molten metal-sand mold

    OpenAIRE

    Z. Janjuševi?; Z. Gulišija; M. Mihailovi?; A. Patari?

    2014-01-01

    The processes that take place at the liquid metal-sand mold interface during the casting and crystallization of metal were studied in this paper. The mold was made using the CO2 – method, with the addition of active components, such as: MgO, TiO2, AlK(SO4)2 and Na2SO4. At the liquid steel pouring temperature, these active components undergo decomposition in the mold, caused by heat release during pouring, crystallization and cooling of castings. Silicates, which have an important influence on...

  2. Transcription of Small Surface Structures in Injection Molding - an Experimental Study

    DEFF Research Database (Denmark)

    Arlø, Uffe Rolf; Kjær, Erik Michael

    2001-01-01

    The ability to replicate the surface roughness from mold wall to the plastic part in injection moldning has many functional and cosmetic important implications from medical use to designer products. Generally the understanding of surface transcription i.e the the replication of the surface structure from the mould to plastic part, also relates to micro injection moulding and moulding of parts with specific micro structures on the surface such as optical parts. The present study concerns transcri...

  3. Injection molding of nanopatterned surfaces in the sub-micrometer range with induction heating aid

    DEFF Research Database (Denmark)

    Menotti, Stefano; Hansen, Hans NØrgaard

    2014-01-01

    Replication of sub-micrometer structures by injection molding leads to special requirements for the mold in order to ensure proper replica and acceptable cycle time. This paper investigates the applicability of induction heating embedded into the mold for the improvement of nanopattern replication. A tool insert having a surface containing functional geometries in the sub-micrometer range was produced using aluminum anodization and nickel electroplating. In order to provide elevated mold temperatures necessary for the complete replica of the pattern, a new mold setup was developed, which allows rapid heating of the cavity wall using an induction heating system. Temperature was measured using a thermocouple placed in the mold insert. The system was used to heat up the cavity wall with heating rates of up to 10 K/s. Acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) were used as materials, and heating parameters were investigated after a preliminary optimization with standard heating conditions. The replicated surfaces were quantitatively characterized by atomic force microscopy using specific three-dimensional surface amplitude parameters and qualitatively inspected by scanning electron microscopy. The experimental results show that the use of the induction heating system is an efficient way for improving nanoreplication.

  4. Recycling process of casting molds applying to precision castings

    OpenAIRE

    M. Drajewicz; Pytel, M.

    2012-01-01

    Purpose: The present work relates to investigations about the possibility of recycling and producing sinters from ceramic molds. These molds are applied for producing precise single crystal casts of nickel based superalloys to elements witch are applied to the hot section of aircraft jet engines.Design/methodology/approach: The processes of milling were carried out using the vibratory mill Herzog HSM 100H and the planetary grinder Pulverisette 7 - Fritsch Company. The measurements of all kind...

  5. Low Speed Technology for Small Turbine Development Reaction Injection Molded 7.5 Meter Wind Turbine Blade

    Energy Technology Data Exchange (ETDEWEB)

    David M. Wright; DOE Project Officer - Keith Bennett

    2007-07-31

    An optimized small turbine blade (7.5m radius) was designed and a partial section molded with the RIM (reaction-injection molded polymer) process for mass production. The intended market is for generic three-bladed wind turbines, 100 kilowatts or less, for grid-assist end users with rural and semi-rural sites, such as the farm/ranch market, having low to moderate IEC Class 3-4 wind regimes. This blade will have substantial performance improvements over, and be cheaper than, present-day 7.5m blades. This is made possible by the injection-molding process, which yields high repeatability, accurate geometry and weights, and low cost in production quantities. No wind turbine blade in the 7.5m or greater size has used this process. The blade design chosen uses a RIM skin bonded to a braided infused carbon fiber/epoxy spar. This approach is attractive to present users of wind turbine blades in the 5-10m sizes. These include rebladeing California wind farms, refurbishing used turbines for the Midwest farm market, and other manufacturers introducing new turbines in this size range.

  6. Progress in modeling long glass and carbon fiber breakage during injection molding

    Science.gov (United States)

    Chen, Hongyu; Cieslinski, Mark; Baird, Donald G.

    2015-05-01

    This work is concerned with the modeling of in-machine fiber breakage during injection molding. A lab-scale single screw extruder is used to evaluate fiber breakage in the screw. Our experiments show that as the initial glass fiber pellets length is reduced relative to the channel width, the overall percent of breakage is reduced. We believe that the ratio of initial pellet length to the screw channel width, or diameter, is an important parameter determining the percent of fiber breakage. Data have been fit using an exponential decay model with a kinetic decay constant and a critical length value. This empirical model has been tested on an injection molding machine with a screw 1.6 times larger than that of our single screw extruder. The predicted average fiber length leaving the nozzle shows reasonable agreement with the measured value. For the injection molded end-gated-plaque produced by the same machine, additional fiber breakage has been observed in the runner. A hydrodynamic force based breakage model is combined with mold filling simulation to simulate the fiber breakage in the runner. For carbon fibers, similar breakage trends were observed in the single screw extruder indicating the applicability of our empirical model to carbon fiber.

  7. Experimental Study of Fiber Length and Orientation in Injection Molded Natural Fiber/Starch Acetate Composites

    DEFF Research Database (Denmark)

    Peltola, Heidi; Madsen, Bo

    2011-01-01

    Composite compounds based on triethyl citrate plasticized starch acetate and hemp and flax fibers were prepared by melt processing. Plasticizer contents from 20 to 35 wt% and fiber contents of 10 and 40 wt% were used. The compounded composites were injection molded to tensile test specimens. The effect of processing, melt viscosity and fiber type on the fiber length was investigated. The lengths of fully processed fibers were determined by dissolving the matrix and measuring the length of the remaining fibers by microscope analysis. A clear reductive effect of the processing on the fiber length was noticed. A reduction of fiber length along the increasing fiber content and the decreasing plasticizer content was also detected. This reduction originated from the increasing shear forces during compounding, which again depended on the increased viscosity of the material. Hemp fibers were shown to remain longer and fibrillate more than flax fibers, leading to higher aspect ratio. Thus, the reinforcement efficiencyof hemp fibers by the processing was improved, in contrast with flax fibers. In addition, the analysis of fiber dispersion and orientation showed a good dispersion of fibers in the matrix, and a predominant orientation of the fibers in the melt flow direction.

  8. Predictive Engineering Tools for Injection-molded Long-Carbon-Fiber Thermoplastic Composites - FY 2014 Third Quarterly Report

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep; Sanborn, Scott E.; Mathur, Raj N.; Sharma, Bhisham; Sangid, Michael D.; Wang, Jin; Jin, Xiaoshi; Costa, Franco; Gandhi, Umesh N.; Mori, Steven; Tucker III, Charles L.

    2014-08-15

    This report describes the technical progresses made during the third quarter of FY 2014: 1) Autodesk introduced the options for fiber inlet condition to the 3D solver. These options are already available in the mid-plane/dual domain solver. 2) Autodesk improved the accuracy of 3D fiber orientation calculation around the gate. 3) Autodesk received consultant services from Prof. C.L. Tucker at the University of Illinois on the implementation of the reduced order model for fiber length, and discussed with Prof. Tucker the methods to reduce memory usage. 4) PlastiComp delivered to PNNL center-gated and edge-fan-gated 20-wt% to 30-wt% LCF/PP and LCF/PA66 (7”x7”x1/8”) plaques molded by the in-line direct injection molding (D-LFT) process. 5) PlastiComp molded ASTM tensile, flexural and impact bars under the same D-LFT processing conditions used for plaques for Certification of Assessment and ascertaining the resultant mechanical properties. 6) Purdue developed a new polishing routine, utilizing the automated polishing machine, to reduce fiber damage during surface preparation. 7) Purdue used a marker-based watershed segmentation routine, in conjunction with a hysteresis thresholding technique, for fiber segmentation during fiber orientation measurement. 8) Purdue validated Purdue’s fiber orientation measurement method using the previous fiber orientation data obtained from the Leeds machine and manually measured data by the University of Illinois. 9) PNNL conducted ASMI mid-plane analyses for a 30wt% LCF/PP plaque and compared the predicted fiber orientations with the measured data provided by Purdue University at the selected locations on this plaque. 10) PNNL put together the DOE 2014 Annual Merit Review (AMR) presentation with the team and presented it at the AMR meetings on June 17, 2014. 11) PNNL built ASMI dual domain models for the Toyota complex part and commenced mold filling analyses of the complex part with different wall thicknesses in order to support part molding. 12) Toyota and Magna discussed with PNNL on tool modification for molding the complex part. Toyota sent the CAD files of the complex part to PNNL to build ASMI models of the part for mold filling analysis to provide guidance to tooling and part molding.

  9. Evolução da morfologia de fases de blendas PA6/AES em extrusora de dupla rosca e moldagem por injeção / Evolution of phase morphology of PA6/AES blends during the twin screw extrusion and injection molding processes

    Scientific Electronic Library Online (English)

    Adriane, Bassani; Elias, Hage Jr; Luiz A., Pessan; Ana V, Machado; José A., Covas.

    2005-07-01

    Full Text Available A evolução da morfologia de fases em blendas não reativas e reativas de poliamida-6 com copolímero de acrilonitrila/EPDM/estireno (AES) em uma extrusora de rosca dupla co-rotacional foi investigada. A evolução da morfologia de fases ao longo da extrusora de rosca dupla foi monitorada através da cole [...] ta de pequenas amostras em válvulas no barril da extrusora e caracterização por microscopia eletrônica de transmissão (MET). Foram utilizados como compatibilizantes reativos os copolímeros metacrilato de metila-co-anidrido maleico (MMA-MA) e metacrilato de metila-co-metacrilato de glicidila (MMA-GMA). Os grupos anidrido maleico e epóxi nos copolímeros podem reagir com os grupos finais de cadeia da poliamida durante o processamento no estado fundido e melhorar a interação na interfase do sistema PA6/AES. A blenda PA6/AES não compatibilizada apresentou uma morfologia grosseira de fases onde a fase AES não está bem dispersa na matriz de PA6 devido à falta de interações adequadas entre os componentes da blenda. A adição do compatibilizante MMA-GMA não proporcionou boa dispersão de fases e não melhorou as propriedades mecânicas da blenda, provavelmente porque as possíveis reações no sistema são lentas e podem não ocorrer na extrusora. Por outro lado, a blenda compatibilizada com o copolímero MMA-MA apresentou uma excelente resistência ao impacto à temperatura ambiente e uma diminuição na temperatura de transição dúctil-frágil. As partículas de AES apresentam-se muito mais refinadas e sofrem uma redução significativa em seu tamanho já no início do processo de extrusão. A morfologia observada nas amostras injetadas apresentou uma boa correlação com as propriedades mecânicas obtidas. Abstract in english The evolution of phase morphology in non-reactive vs reactive blends with polyamide and ethylene-propylene-diene elastomer grafted with styrene-acrylonitrile copolymer (AES) in a co-rotating twin-screw extruder was investigated. The morphological evolution of these blends along a twin-screw extruder [...] was monitored by quickly collecting small samples from the melt at specific extruder barrel locations and characterizing them with a transmission electron microscope (TEM). The copolymers methyl methacrylate-co-maleic anhydride (MMA-MA) and methyl methacrylate-co-glycidyl methacrylate (MMA-GMA) were used as compatibilizing agents. The maleic anhydride and the epoxy groups of the copolymers can react with the polyamide end groups during melt processing and improve the interphase interaction in the PA6/AES system. The uncompatibilized blends showed a coarse phase morphology where the AES phase is not well dispersed in the PA6 matrix due to lack of adequate interaction between the components. The addition of MMA-GMA compatibilizer neither promoted good phase dispersion or improved the mechanical properties of the blends, probably because the possible reactions are very slow and may not occur inside the extruder. On the other hand, the addition of the MMA-MA copolymer promotes better impact strength and good phase dispersion in the blend. The AES particles undergo significant reduction in the first stages of the mixture inside the extruder. The morphology observed for the injection molded specimens was correlated with the mechanical properties.

  10. Unique opportunities in powder injection molding of refractory and hard materials

    International Nuclear Information System (INIS)

    Powder injection molding (PIM) is a relatively new manufacturing process for the creation of complicated net-shapes outside the range usually possible via powder metallurgy technologies. This new process is now in production at more than 550 sites around the world. Although a small industry, PIM will soon pass $1 billion dollars (USA) in annual sales. This presentation overviews the PIM process, some of the new developments and some of the successes that have occurred with both refractory metals and hard metals. Example applications are seen in medical and dental devices, industrial components, wristwatches, jet engines, firearms, automotive components, and even hand tools. To help establish the novel growth opportunities, PIM is compared to other fabrication routes to better understand the design features arising with this new approach, providing a compelling case for substantial opportunities in the refractory and hard materials. Illustrations are provided of several components in production. New opportunities abound for the technology, since it eliminates the shape complexity barrier associated with die compaction and the cost of machining associated with complicated or dimensionally precise components. Further, a relative cost advantage exists for refractory and hard materials because PIM can use the same powders at the same prices as employed in alternative processes. Future successes will occur by early identification of candidate materials and designs. Early examples include tungsten heavy alloy components now reaching production rates of six million per month. (author)

  11. The role of clay nanoparticles on the development of structural hierarchy in injection molding of nylon 6 and uniaxial stretching of poly(vinyl chloride)

    Science.gov (United States)

    Yalcin, Baris

    The main thrust of this dissertation is to investigate the role of nanoparticles in the structural formation processes that take place in a typical melt processing: injection molding, and in a rubbery state processing: uniaxial film stretching. For melt processing we selected the Nylon-6/clay nanoparticle system as an example and for the rubbery state processing we selected PVC/plasticizer/Clay nanoparticle systems. The effect of platelet type nanoparticles and processing conditions (mold temperature and injection speed) on the development of 'local' microstructure in injection molded nylon 6 parts was investigated. Nanoplatelets induce high levels of orientation of the polymer matrix throughout the thickness of the molded part even at high mold temperatures where nonisothermal effects are highly suppressed and confined to very close proximity of surfaces. These high chain orientation levels observed in nanoparticle filled systems are a result of the shear amplification effect that occurs in small spaces between adjacent nanoparticles of differing velocity. At low mold temperature, 50°C, the structure of unfilled nylon 6 is made up of a steep structural gradient containing oriented threads at the surface surrounding undeformed spherulites in the interior. In nanocomposite samples, on the other hand, the development of complete spherulites is interrupted by high nucleation density caused by the presence of nanoparticles and shear amplification that occurs in small spaces between these particles. The latter phenomenon was found to be prevalent even at high mold temperatures where the cooling rates are greatly suppressed. In the structure gradient, polymer/nanocomposite samples show double shear regions near the surface surrounding the core regions that contain sheaves. The origin of complex superimposed SALS patterns is explained in terms of the short and long-range spatial correlations of these preferentially oriented sheaves and their optic axes. (Abstract shortened by UMI.)

  12. Application of Rapid Prototyping and Wire Arc Spray to the Fabrication of Injection Mold Tools (MSFC Center Director's Discretionary Fund)

    Science.gov (United States)

    Cooper, K. G.

    2000-01-01

    Rapid prototyping (RP) is a layer-by-layer-based additive manufacturing process for constructing three-dimensional representations of a computer design from a wax, plastic, or similar material. Wire arc spray (WAS) is a metal spray forming technique, which deposits thin layers of metal onto a substrate or pattern. Marshall Space Flight Center currently has both capabilities in-house, and this project proposed merging the two processes into an innovative manufacturing technique, in which intermediate injection molding tool halves were to be fabricated with RP and WAS metal forming.

  13. Optimizing the Filling Time and Gate of the Injection Mold on Plastic Air Intake Manifold of Engines

    OpenAIRE

    Shiqiang Zhang

    2013-01-01

    In order to acquire the best filling time, Mold trial is made by setting different injection time, or Mold flow software is used to analyze data recorded by computer. Whether doing successive trials or being simulated point by point, is very tedious. A new method is put forward-seeking the minimum of curve being simulated by Lagrange interpolation. The minimum of the curve is the best filling time. This method can improve the efficiency of the simulation analysis. The software Mold flow...

  14. Electroforming of Tool Inserts for Injection Molding of Optical or Microfluidic Components

    DEFF Research Database (Denmark)

    Tang, Peter Torben; Christensen, Thomas R.; Jensen, Martin F.

    2004-01-01

    With a rapidly increasing international interest in “Lab-on-a-chip”-systems as well as affordable polymer optics, the combination of electroforming and injection molding offers an attractive fabrication solution. Miniaturized analysis systems can be used for medical, security (anti terror...... monitoring) and environmental (waste water monitoring) applications. Optical components in polymer materials can be used for consumer electronics and for sensor systems. The presentation will include the complete fabrication scheme for tool inserts based on machining and electroforming. Electroforming...

  15. Forehead Augmentation with a Methyl Methacrylate Onlay Implant Using an Injection-Molding Technique

    Directory of Open Access Journals (Sweden)

    Dong Kwon Park

    2013-09-01

    Full Text Available Background The forehead, which occupies about one third of the face, is one of the majordeterminants of a feminine or masculine look. Various methods have been used for the augmentationof the forehead using autologous fat grafts or alloplastic materials. Methylmethacrylate(MMA is the most appropriate material for augmentation of the forehead, and we have usedan injection-molding technique with MMA to achieve satisfactory results.Methods Under local anesthesia with intravenous (IV sedation, an incision was made onthe scalp and a meticulous and delicate subperiosteal dissection was then performed. MMAmonomers and polymers were mixed, the dough was injected into the space created, andmanual molding was performed along with direct inspection. This surgery was indicated forpatients who wanted to correct an unattractive appearance by forehead augmentation. Everypatient in this study visited our clinics 3 months after surgery to evaluate the results. Wejudged the postoperative results in terms of re-operation rates caused by the dissatisfactionof the patients and complications.Results During a 13-year period, 516 patients underwent forehead augmentation with MMA.With the injection-molding technique, the inner surface of the MMA implant is positionedclose to the underlying frontal bone, which minimizes the gap between the implant and bone.The borders of the implant should be tapered sufficiently until no longer palpable or visible.Only 28 patients (5.4% underwent a re-operation due to an undesirable postoperative appearance.Conclusions The injection-molding technique using MMA is a simple, safe, and ideal methodfor the augmentation of the forehead.

  16. Forehead Augmentation with a Methyl Methacrylate Onlay Implant Using an Injection-Molding Technique

    OpenAIRE

    Dong Kwon Park; Ingook Song; Jin Hyo Lee; Young June You

    2013-01-01

    Background The forehead, which occupies about one third of the face, is one of the majordeterminants of a feminine or masculine look. Various methods have been used for the augmentationof the forehead using autologous fat grafts or alloplastic materials. Methylmethacrylate(MMA) is the most appropriate material for augmentation of the forehead, and we have usedan injection-molding technique with MMA to achieve satisfactory results.Methods Under local anesthesia with intravenous (IV) sedation, ...

  17. Injection molded chips with integrated conducting polymer electrodes for electroporation of cells

    DEFF Research Database (Denmark)

    Andresen, Kristian; Hansen, Morten; Matschuk, Maria; Jepsen, Søren Terpager; Sørensen, Henrik Schiøtt; Utko, Pawel; Selmeczi, Dávid; Hansen, Thomas Steen; Larsen, Niels Bent; Rozlosnik, Noemi; Taboryski, Rafael Jozef

    2010-01-01

    We present the design-concept for an all polymer injection molded single use microfluidic device. The fabricated devices comprise integrated conducting polymer electrodes and Luer fitting ports to allow for liquid and electrical access. A case study of low voltage electroporation of biological cells in suspension is presented. The working principle of the electroporation device is based on a focusing of the electric field by means of a constriction in the flow channel for the cells. We demonstra...

  18. Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites

    OpenAIRE

    Ueberschaer, A.; Cagiao, M.E.; Bayer, R. K.; Henning, S; Baltá Calleja, F. J.

    2006-01-01

    The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions. The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence were evaluated in terms of the indepe...

  19. Indirect three-dimensional printing of synthetic polymer scaffold based on thermal molding process

    International Nuclear Information System (INIS)

    One of the major issues in tissue engineering has been the development of three-dimensional (3D) scaffolds, which serve as a structural template for cell growth and extracellular matrix formation. In scaffold-based tissue engineering, 3D printing (3DP) technology has been successfully applied for the fabrication of complex 3D scaffolds by using both direct and indirect techniques. In principle, direct 3DP techniques rely on the straightforward utilization of the final scaffold materials during the actual scaffold fabrication process. In contrast, indirect 3DP techniques use a negative mold based on a scaffold design, to which the desired biomaterial is cast and then sacrificed to obtain the final scaffold. Such indirect 3DP techniques generally impose a solvent-based process for scaffold fabrication, resulting in a considerable increase in the fabrication time and poor mechanical properties. In addition, the internal architecture of the resulting scaffold is affected by the properties of the biomaterial solution. In this study, we propose an advanced indirect 3DP technique using projection-based micro-stereolithography and an injection molding system (IMS) in order to address these challenges. The scaffold was fabricated by a thermal molding process using IMS to overcome the limitation of the solvent-based molding process in indirect 3DP techniques. The results indicate that the thermal molding process using an IMS has achieved a substantial reduction in scaffold fabrication time and has also provided the scaffold with higher mechanical modulus and strength. In addition, cell adhesion and proliferation studies have indicated no significant difference in cell activity between the scaffolds prepared by solvent-based and thermal molding processes. (paper)

  20. Indirect three-dimensional printing of synthetic polymer scaffold based on thermal molding process.

    Science.gov (United States)

    Park, Jeong Hun; Jung, Jin Woo; Kang, Hyun-Wook; Cho, Dong-Woo

    2014-06-01

    One of the major issues in tissue engineering has been the development of three-dimensional (3D) scaffolds, which serve as a structural template for cell growth and extracellular matrix formation. In scaffold-based tissue engineering, 3D printing (3DP) technology has been successfully applied for the fabrication of complex 3D scaffolds by using both direct and indirect techniques. In principle, direct 3DP techniques rely on the straightforward utilization of the final scaffold materials during the actual scaffold fabrication process. In contrast, indirect 3DP techniques use a negative mold based on a scaffold design, to which the desired biomaterial is cast and then sacrificed to obtain the final scaffold. Such indirect 3DP techniques generally impose a solvent-based process for scaffold fabrication, resulting in a considerable increase in the fabrication time and poor mechanical properties. In addition, the internal architecture of the resulting scaffold is affected by the properties of the biomaterial solution. In this study, we propose an advanced indirect 3DP technique using projection-based micro-stereolithography and an injection molding system (IMS) in order to address these challenges. The scaffold was fabricated by a thermal molding process using IMS to overcome the limitation of the solvent-based molding process in indirect 3DP techniques. The results indicate that the thermal molding process using an IMS has achieved a substantial reduction in scaffold fabrication time and has also provided the scaffold with higher mechanical modulus and strength. In addition, cell adhesion and proliferation studies have indicated no significant difference in cell activity between the scaffolds prepared by solvent-based and thermal molding processes. PMID:24658060

  1. Moldagem por injeção da PA 6.6 em moldes de estereolitografia metalizados com Ni-P pelo processo electroless / Injection molding of PA 6.6 in stereolithography moulds coated with electroless Ni-P

    Scientific Electronic Library Online (English)

    Diovani C., Lencina; Carlos H., Ahrens; Gean V., Salmoria; Fernando H., Lafratta.

    2007-06-01

    Full Text Available A fabricação de moldes por técnicas de prototipagem rápida, como a estereolitografia (SL), é considerada uma importante tecnologia no auxílio ao desenvolvimento de produtos de plástico moldados por injeção. Embora esta tecnologia se mostre vantajosa, a vida útil dos moldes pode ser bastante reduzida [...] em decorrência, por exemplo, de forte adesão entre o polímero injetado e o material do molde SL. Neste trabalho é investigado o uso da técnica de recobrimento metálico com Ni-P por deposição electroless sobre moldes de injeção, fabricados por SL com a resina DSM SOMOS 7110®. Foram comparados resultados de moldagem de PA6.6 em moldes fabricados com e sem recobrimento metálico evidenciando a possibilidade de utilizar a técnica de metalização como alternativa para a moldagem deste material em moldes SL, uma vez que a vida útil foi superior. Abstract in english Manufacturing of moulds by rapid prototyping processes, such as stereolithography (SL), is considered an important technology to aid the development of injection moulding plastic products. Although this technology shows significant advantages, the lifetime of moulds may be drastically be reduced due [...] to strong adhesion between the injected polymer and the material of the SL mould. This work investigates the use of Ni-P metal coating obtained by electroless deposition on SL moulds manufactured with the resin DSM SOMOS 7110. Specimens of PA6.6 have been injected into SL moulds manufactured with and without metal coating. The results showed that the electroless metal coating process can be an appropriate alternative to allow moulding of small series of PA6.6 parts in SL moulds.

  2. Moldagem por injeção da PA 6.6 em moldes de estereolitografia metalizados com Ni-P pelo processo electroless Injection molding of PA 6.6 in stereolithography moulds coated with electroless Ni-P

    Directory of Open Access Journals (Sweden)

    Diovani C. Lencina

    2007-06-01

    Full Text Available A fabricação de moldes por técnicas de prototipagem rápida, como a estereolitografia (SL, é considerada uma importante tecnologia no auxílio ao desenvolvimento de produtos de plástico moldados por injeção. Embora esta tecnologia se mostre vantajosa, a vida útil dos moldes pode ser bastante reduzida em decorrência, por exemplo, de forte adesão entre o polímero injetado e o material do molde SL. Neste trabalho é investigado o uso da técnica de recobrimento metálico com Ni-P por deposição electroless sobre moldes de injeção, fabricados por SL com a resina DSM SOMOS 7110®. Foram comparados resultados de moldagem de PA6.6 em moldes fabricados com e sem recobrimento metálico evidenciando a possibilidade de utilizar a técnica de metalização como alternativa para a moldagem deste material em moldes SL, uma vez que a vida útil foi superior.Manufacturing of moulds by rapid prototyping processes, such as stereolithography (SL, is considered an important technology to aid the development of injection moulding plastic products. Although this technology shows significant advantages, the lifetime of moulds may be drastically be reduced due to strong adhesion between the injected polymer and the material of the SL mould. This work investigates the use of Ni-P metal coating obtained by electroless deposition on SL moulds manufactured with the resin DSM SOMOS 7110. Specimens of PA6.6 have been injected into SL moulds manufactured with and without metal coating. The results showed that the electroless metal coating process can be an appropriate alternative to allow moulding of small series of PA6.6 parts in SL moulds.

  3. Evaluation of hot-melt extrusion and injection molding for continuous manufacturing of immediate-release tablets.

    Science.gov (United States)

    Melocchi, Alice; Loreti, Giulia; Del Curto, Maria Dorly; Maroni, Alessandra; Gazzaniga, Andrea; Zema, Lucia

    2015-06-01

    The exploitation of hot-melt extrusion and injection molding for the manufacturing of immediate-release (IR) tablets was preliminarily investigated in view of their special suitability for continuous manufacturing, which represents a current goal of pharmaceutical production because of its possible advantages in terms of improved sustainability. Tablet-forming agents were initially screened based on processability by single-screw extruder and micromolding machine as well as disintegration/dissolution behavior of extruded/molded prototypes. Various polymers, such as low-viscosity hydroxypropylcellulose, polyvinyl alcohol, polyvinyl alcohol-polyethylene glycol graft copolymer, various sodium starch glycolate grades (e.g., Explotab(®) CLV) that could be processed with no need for technological aids, except for a plasticizer, were identified. Furthermore, the feasibility of both extruded and molded IR tablets from low-viscosity hydroxypropylcellulose or Explotab(®) CLV was assessed. Explotab(®) CLV, in particular, showed thermoplastic properties and a very good aptitude as a tablet-forming agent, starting from which disintegrating tablets were successfully obtained by either techniques. Prototypes containing a poorly soluble model drug (furosemide), based on both a simple formulation (Explotab(®) CLV and water/glycerol as plasticizers) and formulations including dissolution/disintegration adjuvants (soluble and effervescent excipients) were shown to fulfill the USP 37 dissolution requirements for furosemide tablets. PMID:25761921

  4. Structural scheme optimization design for the stationary platen of a precision plastic injection molding machine

    Science.gov (United States)

    Ren, Bin; Zhang, Shuyou; Tan, Jianrong

    2014-07-01

    The current development of precision plastic injection molding machines mainly focuses on how to save material and improve precision, but the two aims contradict each other. For a clamp unit, clamping precision improving depends on the design quality of the stationary platen. Compared with the parametric design of stationary platen, structural scheme design could obtain the optimization model with double objectives and multi-constraints. In this paper, a SE-160 precision plastic injection molding machine with 1600 kN clamping force is selected as the subject in the case study. During the motion of mold closing and opening, the stationary platen of SE-160 is subjected to a cyclic loading, which would cause the fatigue rupture of the tie bars in periodically long term operations. In order to reduce the deflection of the stationary platen, the FEA method is introduced to optimize the structure of the stationary platen. Firstly, an optimal topology model is established by variable density method. Then, structural topology optimizations of the stationary platen are done with the removable material from 50%, 60% to 70%. Secondly, the other two recommended optimization schemes are given and compared with the original structure. The result of performances comparison shows that the scheme II of the platen is the best one. By choosing the best alternative, the volume and the local maximal stress of the platen could be decreased, corresponding to cost-saving material and better mechanical properties. This paper proposes a structural optimization design scheme, which can save the material as well as improve the clamping precision of the precision plastic injection molding machine.

  5. An injection molded microchip for nucleic acid purification from 25 microliter samples using isotachophoresis.

    Science.gov (United States)

    Marshall, L A; Rogacs, A; Meinhart, C D; Santiago, J G

    2014-02-28

    We present a novel microchip device for purification of nucleic acids from 25?L biological samples using isotachophoresis (ITP). The device design incorporates a custom capillary barrier structure to facilitate robust sample loading. The chip uses a 2mm channel width and 0.15mm depth to reduce processing time, mitigate Joule heating, and achieve high extraction efficiency. To reduce pH changes in the device due to electrolysis, we incorporated a buffering reservoir physically separated from the sample output reservoir. To reduce dispersion of the ITP-focused zone, we used optimized turn geometries. The chip was fabricated by injection molding PMMA and COC plastics through a commercial microfluidic foundry. The extraction efficiency of nucleic acids from the device was measured using fluorescent quantification, and an average recovery efficiency of 81% was achieved for nucleic acid masses between 250pg and 250ng. The devices were also used to purify DNA from whole blood, and the extracted DNA was amplified using qPCR to show the PCR compatibility of the purified sample. PMID:24485540

  6. Thermal and mechanical behavior of injection molded Poly(3-hydroxybutyrate/Poly(epsilon-caprolactone blends

    Directory of Open Access Journals (Sweden)

    Marcia Adriana Tomaz Duarte

    2006-03-01

    Full Text Available Aiming the development of high-performance biodegradable polymer materials, the properties and the processing behavior of poly(3-hydroxybutyrate, P(3HB, and their blends with poly(epsilon-caprolactone, PCL, have been investigated. The P(3HB sample, obtained from sugarcane, had a molecular weight of 3.0 x 10(5 g.mol¹, a crystallinity degree of 60%, a glass transition temperature (Tg, at - 0.8 °C, and a melting temperature at 171 °C. The molecular weight of PCL was 0.8 x 10(5 g.mol-1. Specimens of 70/30 wt. (% P(3HB/PCL blends obtained by injection molding showed tensile strength of 21.9 (± 0.4 MPa, modulus of 2.2 (± 0.3 GPa, and a relatively high elongation at break, 87 (± 20%. DSC analyses of this blend showed two Tg´s, at - 10.6 °C for the P(3HB matrix, and at - 62.9 °C for the PCL domains. The significant decrease on the Tg of P(3HB evidences a partial miscibility of PCL in P(3HB. According to the Fox equation, the new Tg corresponds to a 92/8 wt. (% P(3HB/PCL composition.

  7. Thermal and mechanical behavior of injection molded Poly(3-hydroxybutyrate)/Poly(epsilon-caprolactone) blends

    Scientific Electronic Library Online (English)

    Marcia Adriana Tomaz, Duarte; Roberson Goulart, Hugen; Eduardo Sant' Anna, Martins; Ana Paula Testa, Pezzin; Sérgio Henrique, Pezzin.

    2006-03-01

    Full Text Available Aiming the development of high-performance biodegradable polymer materials, the properties and the processing behavior of poly(3-hydroxybutyrate), P(3HB), and their blends with poly(epsilon-caprolactone), PCL, have been investigated. The P(3HB) sample, obtained from sugarcane, had a molecular weight [...] of 3.0 x 10(5) g.mol¹, a crystallinity degree of 60%, a glass transition temperature (Tg), at - 0.8 °C, and a melting temperature at 171 °C. The molecular weight of PCL was 0.8 x 10(5) g.mol-1. Specimens of 70/30 wt. (%) P(3HB)/PCL blends obtained by injection molding showed tensile strength of 21.9 (± 0.4) MPa, modulus of 2.2 (± 0.3) GPa, and a relatively high elongation at break, 87 (± 20)%. DSC analyses of this blend showed two Tg´s, at - 10.6 °C for the P(3HB) matrix, and at - 62.9 °C for the PCL domains. The significant decrease on the Tg of P(3HB) evidences a partial miscibility of PCL in P(3HB). According to the Fox equation, the new Tg corresponds to a 92/8 wt. (%) P(3HB)/PCL composition.

  8. Microstructure and Mechanical Performance Analysis of Metal-injection-molded Fe-2Ni Sintered Components

    Science.gov (United States)

    Lin, Kuan-Hong; Hsieh, Yu-Chan; Lin, Shun-Tian

    2011-01-01

    The influence of iron powders and heat treating processes on the microstructure, mechanical properties, wear properties and fracture modes of the metal injection molded Fe-2Ni (wt.%) components were investigated in this work. Experimental results indicated that the components using BASF-OS grade carbonyl iron powder showed a finer grains and lower residual carbon content than that using BASF-OM grade carbonyl iron powder. It was observed that the hardness and wear-resistance of the carburized and quenched OS-grade components decreased as the tempering temperature was higher. On the other hand, BASF-OM grade carbonyl iron powder sintered components maintained original carbon contents and lower hardness than that of BASF OS-grade specimen. Dramatic fluctuations of friction forces were observed on the BASF-OS grade and BASF-OM grade components, which were tempered between 100-150° C and 300° C, respectively. It was believed that such phenomena were caused by the difference of wear modes and had detrimental effects on the life time of components.

  9. Wall-slip of highly filled powder injection molding compounds: Effect of flow channel geometry and roughness

    Energy Technology Data Exchange (ETDEWEB)

    Hausnerova, Berenika; Sanetrnik, Daniel [Dept. of Production Engineering, Faculty of Technology, Tomas Bata University in Zlin, nám. T.G. Masaryka 5555, 760 01 Zlín, Czech Republic and Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Nad Ovc (Czech Republic); Paravanova, Gordana [Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Nad Ovcírnou 3685, 760 01 Zlín (Czech Republic)

    2014-05-15

    The paper deals with the rheological behavior of highly filled compounds proceeded via powder injection molding (PIM) and applied in many sectors of industry (automotive, medicine, electronic or military). Online rheometer equipped with slit dies varying in surface roughness and dimensions was applied to investigate the wall-slip as a rheological phenomenon, which can be considered as a parameter indicating the separation of compound components (polymer binder and metallic powder) during high shear rates when injection molded.

  10. Injection Molding of Titanium Alloy Implant For Biomedical Application Using Novel Binder System Based on Palm Oil Derivatives

    Directory of Open Access Journals (Sweden)

    R. Ibrahim

    2010-01-01

    Full Text Available Problem statement: Titanium alloy (Ti6Al4V has been widely used as an implant for biomedical application. In this study, the implant had been fabricated using high technology of Powder Injection Molding (PIM process due to the cost effective technique for producing small, complex and precision parts in high volume compared with conventional method through machining. Approach: Through PIM, the binder system is one of the most important criteria in order to successfully fabricate the implants. Even though, the binder system is a temporary, but failure in the selection and removal of the binder system will affect on the final properties of the sintered parts. Therefore, the binder system based on palm oil derivative which is palm stearin had been formulated and developed to replace the conventional binder system. Results: The rheological studies of the mixture between the powder and binders system had been determined properly in order to be successful during injection into injection molding machine. After molding, the binder held the particles in place. The binder system had to be removed completely through debinding step. During debinding step, solvent debinding and thermal pyrolysis had been used to remove completely of the binder system. The debound part was then sintered to give the required physical and mechanical properties. The in vitro biocompatibility also was tested using Neutral Red (NR and mouse fibroblast cell lines L-929 for the direct contact assay. Conclusion: The results showed that the properties of the final sintered parts fulfill the Standard Metal Powder Industries Federation (MPIF 35 for PIM parts except for tensile strength and elongation due to the formation of titanium carbide. The in vitro biocompatibility on the extraction using mouse fibroblast cell line L-929 by means of NR assays showed non toxic for the sintered specimen titanium alloy parts.

  11. Development of production technology by metallic powder injection molding for TiAl-type intermetallic compound with high efficiency

    International Nuclear Information System (INIS)

    Since a TiAl-type intermetallic compound has an excellent high temperature strength and corrosion resistance, in addition to light weight, it is expected to be applicable to the engine parts. However, it is difficult for TiAI to produce a part with a complex shape, and considerable cost will be required. In this study, it was tried to develop a technology for producing TiAl products with high density and high efficiency by using metal powder injection molding (MIM) process. Several kinds of TiAI alloy powders made by the self-propagating high temperature synthesis process were mixed with an organic binder, kneaded and then injection-molded into tensile specimens. These compacts were subjected to the treatment for removing the binder and sintering, resulted in a relative density as high as 97 %. By room and high temperature tensile tests, it was found that, Ti-47.4Al-2.6Cr (at%) has the strength and ductility as those of the conventional processed materials. (author)

  12. The effect of injection molding conditions on the near-surface rubber morphology, surface chemistry, and adhesion performance of semi-crystalline and amorphous polymers

    Science.gov (United States)

    Weakley-Bollin, Shannon Christine

    This thesis investigated the effect of injection molding processing variables, resin formulation and mold material on the resulting morphology and properties of semi-crystalline and amorphous polymers in parts molded on large presses with fully developed flow. Five different polymer resins and two different coating types were investigated, and the near-surface morphology was found to be dependent on material formulation, processing parameters, and geometry. For painted TPO, changes in the near-surface rubber morphology and surface chemistry based on material and processing conditions had no significant effect on the adhesion performance. For metal plated ABS, the adhesion performance was found to be heavily dependent on the rubber surface morphology, which varied with material formulation and processing conditions. One of the most significant findings was that forged aluminum injection molding tooling had little effect on the surface morphology or adhesion performance of either polypropylene or the two TPO formulations examined, despite the five-fold increase in thermal conductivity over traditional tool steel. Surface chemistry, however, was found to be affected by cooling rate, depending on material formulation. A UV stabilizer additive was found concentrated at 2.5 atomic percent on the surface of the aluminum molded part, but not the steel molded part, demonstrating a possible opportunity for using additives and aluminum tooling to create "designer surfaces". Processing conditions were found to have a competing role in metal plated ABS, where conditions that lowered surface stress and improved adhesion by a factor of 15 also increased the amount of bulk molded-in stress by nearly 7%. Both factors were found to play an important role in adhesion performance due to the effect of surface stress on the quality of the resulting etch structure. The bulk stress must be minimized to due to the large mechanical and thermal mismatch between the polymer and metal layers. This work provides a more in-depth understanding of the effect of processing and material composition on morphology, surface chemistry, molded-in stress and adhesion. This will establish guidelines for future injection molded part designs to alleviate delamination failures and minimize warp, as well as contribute to modeling predictions of shrink and mechanical behavior.

  13. Hybrid tooling technologies for injection molded and hot embossed polymeric microfluidic devices

    Science.gov (United States)

    Becker, Holger; Beckert, Erik; Gärtner, Claudia

    2010-02-01

    The growing complexity of microfluidic devices is currently leading to an increased dimensional scale dynamics, i.e. the range of sizes of features on the microfluidic device is steadily increasing, from centimeter-sized features like reservoirs over millimeter-sized features like fluidic connections and micrometer-sized features like microchannels to nanometersized features like surface textures. In order manufacture these devices with polymer replication technologies like injection molding and hot embossing, molding tools (masters) have to be fabricated which contain the same structural dynamic range. Often, this is not possible using a single tooling technology. We therefore present examples of such tools which have been fabricated using two techniques on the same master structure, namely precision mechanical machining, single-point diamond turning (SPDT) and stereolithography.

  14. Optimization of injection molding process parameters by a hybrid of artificial neural network and artificial bee colony algorithm / Optimización de los parámetros del proceso de inyección de plásticos a través de un híbrido de redes neuronales artificiales y el algoritmo de la colonia artificial de abejas

    Scientific Electronic Library Online (English)

    Alejandro, Alvarado Iniesta; Jorge L., García Alcaraz; ManuelIván, Rodríguez Borbón.

    2013-06-01

    Full Text Available Este estudio presenta un híbrido de redes neuronales artificiales con el algoritmo de la colonia artificial de abejas para optimizar los parámetros del proceso de inyección de plásticos con el objetivo de minimizar la deformación en productos plásticos. Una red neuronal de propagación hacia adelante [...] es empleada para obtener una relación matemática entre los parámetros del proceso y el objetivo a optimizar. El algoritmo de la colonia artificial de abejas es usado para encontrar el conjunto óptimo de valores de los parámetros que resultarían en la solución óptima. Un caso experimental es presentado acoplando simulaciones de Moldflow junto con los esquemas mencionados con el fin de validar el enfoque propuesto. La temperatura del plástico, temperatura del molde, presión de empaque, tiempo de empaque, y tiempo de enfriamiento son consideradas como las variables de diseño. Los resultados revelan que el enfoque propuesto puede eficientemente apoyar a ingenieros a determinar los parámetros óptimos y alcanzar ventajas competitivas en términos de calidad y costos. Abstract in english This paper presents a hybrid of artificial neural networks and artificial bee colony algorithm to optimize the process parameters in injection molding with the aim of minimize warpage of plastic products. A feedforward neural network is employed to obtain a mathematical relationship between the proc [...] ess parameters and the optimization goal. Artificial bee colony algorithm is used to find the optimal set of process parameters values that would result in the optimal solution. An experimental case is presented by coupling Moldflow simulations along with the intelligent schemes in order to validate the proposed approach. Melt temperature, mold temperature, packing pressure, packing time, and cooling time are considered as the design variables. Results revealed the proposed approach can efficiently support engineers to determine the optimal process parameters and achieve competitive advantages in terms of quality and costs.

  15. In-line polariscopic checking of plastic molded-injected lenses: preliminary results

    Science.gov (United States)

    Arasa, J.; Mayershofer, D.; Romero, J.

    2015-05-01

    Plastic injection molded lenses have improved its performance and, nowadays, are as usual as glass lenses in image forming devices. However, the manufacturing process induces the surface generation and the material transformation in the same stage. Moreover, the process also includes an annealing stage to remove the internal stress with temperature cycles but only works up to a certain level and not beyond, leaving relevant traces for high values. During the manufacturing process of a plastic lens, a liquid-solid phase transformation occurs, and in this transition not all the volume of the lens achieves the same density. This change of density is translated into a local change of refractive index that can be expressed as a retardation phase plane using the Jones Matrix notation. The detection and measurement of the value of the retardation of the phase plane is thus the clue to manufacture good and controlled quality plastic lenses. We have tested an in-line polariscopic arrangement to obtain a 2D map of the tension distribution in the bulk of the lens. This test is performed in the first 30 seconds after the injection molding process for two main reasons: first the stress values are still high because the lenses do not have enough time to relax the internal tensions and obtain the final shape, and second, we can remove the wrong lenses in the first moments and introduce only the good lenses in the annealing stage. The proposed instrument is based in a transmission polariscopic arrangement. A collimated light beam is used to illuminate the sample, once the light crosses the sample, it is collected with an afocal system and the image is recorded in a CMOS sensor. Selecting an afocal system to capture the image is a useful decision because the lateral magnification can be maintained when small changes in the sample position are introduced. However the produced lenses can vary their focal lengths from on series to another. To avoid problems with the change of the focal length, the lens is introduced in a matching index and the polariscopic measurement is done. The proposed polariscopic arrangement uses two lineal polarizers, one acting as polarizer and the other acting as analyzer. This system instead of using one lineal polarizer and a lineal polarizer with an extra lambda/4 plate provides us an extra degree of freedom, enabling the possibility to put a certain degree of polarization in a well determined position of the lens, in our case the center of this lens. The aim of this study is to select the minimum number of sets polarizer-analyzer and the right wavelengths to obtain a sure selection of the right lens. The preliminary results show that use two different wavelengths 470 & 627 nm is a good option to obtain a robust image. The second free variables that must be adjusted to obtain good values is the minimum number of set polarizer-analyzer necessary to obtain confident results. In our first tests it seems that recording only at 0, 15, 30 and 45 degrees is enough to get good results. Mathematica description and first results for a PMMA lens are presented, however the number of measurements must be diminished to obtain an easy in-line implementation

  16. Microstructural study of duplex stainless steels obtained by powder injection molding

    Energy Technology Data Exchange (ETDEWEB)

    Sotomayor, M.E., E-mail: msotomay@ing.uc3m.es [Materials Science and Engineering Department, Carlos III University of Madrid, Avda. Universidad 30, 28911 Leganés (Spain); Kloe, R. de, E-mail: rene.de.kloe@ametek.nl [EDAX B. V., PO Box 4144, 5004 JC Tilburg (Netherlands); Levenfeld, B., E-mail: bll@ing.uc3m.es [Materials Science and Engineering Department, Carlos III University of Madrid, Avda. Universidad 30, 28911 Leganés (Spain); Várez, A., E-mail: alvar@ing.uc3m.es [Materials Science and Engineering Department, Carlos III University of Madrid, Avda. Universidad 30, 28911 Leganés (Spain)

    2014-03-15

    Highlights: • The microstructural evolution of sintered PIM duplex stainless steels was studied. • A destabilization of austenite occurs after sintering at high temperature. • Electron backscatter diffraction (EBSD) revealed a remaining of 0.5% of austenite. • Ferrite content was also determined employing a magnetic method. -- Abstract: This experimental work is focused on the study of microstructural evolution during sintering of duplex stainless steels (DSS) obtained by powder injection molding (PIM). Ferritic 430L and austenitic 316L stainless steel powders were previously premixed in a 50/50 volume ratio and afterward they were sintered in low vacuum at different temperatures for 1 h. Microstructural analysis of sintered samples was conducted by means of scanning electron microscopy (SEM) and a compositional analysis of the alloying elements along different phases was performed by energy dispersive analysis of X-rays (EDS). Phase transformations were evaluated by X-ray diffraction (XRD) experiments, and the magnetic phase content was measured with a ferritoscope. The intensity of the main austenite diffraction peak decreases as sintering temperature increases to finally disappear in the sample sintered at 1100 °C. This destabilization of the austenite is probably related to a high Nickel diffusion detected from austenite to ferrite particles. Moreover, electron backscatter diffraction (EBSD) data were collected to quantify microstructural properties. Several EBSD pattern maps were acquired in order to define the amount of austenite phase. Due to the advantages of this technique a 0.5% of austenite could be detected after sintering at 1200 °C. After sintering process, the austenite content in sintered duplex stainless steels obtained through this processing route was lower than expected. Finally, Bain mechanism was proposed as an explanation to this phase transformation takes place. EBSD technique has been proved to be the most suitable to monitor the microstructure of sintered DSS.

  17. Influência do desempenho térmico de moldes fabricados com compósito epóxi/alumínio nas propriedades de pp moldado por injeção / Thermal behavior of epoxy/aluminum rapid tooling composite during injection molding of polypropylene

    Scientific Electronic Library Online (English)

    Gean V., Salmoria; Carlos H., Ahrens; Felix A. Y., Villamizar; Aurélio da C., Sabino Netto.

    2008-09-01

    Full Text Available O surgimento das tecnologias de prototipagem rápida (RP) e de ferramental rápido (RT) tem despertado interesse da indústria de moldes de injeção. O vazamento de termofixos com cargas metálicas possibilita a construção de moldes usando materiais compósitos, os quais apresentam maior resistência que o [...] s utilizados por outras técnicas RT. Neste trabalho foi estudado o comportamento térmico de moldes fabricados em epóxi/alumínio durante a injeção de polipropileno através de avaliações da estrutura e de propriedades mecânicas utilizando difração de raio X e ensaios de dureza e de tração. Os corpos-de-prova injetados no molde em compósito epóxi/alumínio apresentaram pequenas diferenças no grau de cristalinidade das superfícies analisadas e propriedades mecânicas semelhantes aos corpos-de-prova injetados em molde de aço. O estudo mostrou um razoável desempenho térmico do molde compósito durante a injeção de polipropileno evidenciando a viabilidade de utilização destes moldes na produção de pequenas séries de protótipos e de produtos neste termoplástico. Abstract in english rapid prototyping (RP) and rapid tooling (RT) technologies are gaining increasing importance in the injection molding industry. Casting of resin/metal composites allows the construction of molds with greater resistance than those manufactured by other RT techniques such as Stereolithography. In this [...] work, the thermal behavior of molds manufactured in epoxy/aluminum during the injection molding of polypropylene specimens was investigated. Structural and mechanical characterization of the molded specimens included X ray analysis, hardness and tensile testing. The samples presented small differences in the degree of crystallinity and similar mechanical properties in comparison with samples injected into steel molds. This study showed a reasonable thermal performance of the epoxy/aluminum mold during the injection molding of polypropylene, thus demonstrating the viability of using these molds to produce a few number of prototypes or products with this thermoplastic.

  18. Influência do desempenho térmico de moldes fabricados com compósito epóxi/alumínio nas propriedades de pp moldado por injeção Thermal behavior of epoxy/aluminum rapid tooling composite during injection molding of polypropylene

    Directory of Open Access Journals (Sweden)

    Gean V. Salmoria

    2008-09-01

    Full Text Available O surgimento das tecnologias de prototipagem rápida (RP e de ferramental rápido (RT tem despertado interesse da indústria de moldes de injeção. O vazamento de termofixos com cargas metálicas possibilita a construção de moldes usando materiais compósitos, os quais apresentam maior resistência que os utilizados por outras técnicas RT. Neste trabalho foi estudado o comportamento térmico de moldes fabricados em epóxi/alumínio durante a injeção de polipropileno através de avaliações da estrutura e de propriedades mecânicas utilizando difração de raio X e ensaios de dureza e de tração. Os corpos-de-prova injetados no molde em compósito epóxi/alumínio apresentaram pequenas diferenças no grau de cristalinidade das superfícies analisadas e propriedades mecânicas semelhantes aos corpos-de-prova injetados em molde de aço. O estudo mostrou um razoável desempenho térmico do molde compósito durante a injeção de polipropileno evidenciando a viabilidade de utilização destes moldes na produção de pequenas séries de protótipos e de produtos neste termoplástico.rapid prototyping (RP and rapid tooling (RT technologies are gaining increasing importance in the injection molding industry. Casting of resin/metal composites allows the construction of molds with greater resistance than those manufactured by other RT techniques such as Stereolithography. In this work, the thermal behavior of molds manufactured in epoxy/aluminum during the injection molding of polypropylene specimens was investigated. Structural and mechanical characterization of the molded specimens included X ray analysis, hardness and tensile testing. The samples presented small differences in the degree of crystallinity and similar mechanical properties in comparison with samples injected into steel molds. This study showed a reasonable thermal performance of the epoxy/aluminum mold during the injection molding of polypropylene, thus demonstrating the viability of using these molds to produce a few number of prototypes or products with this thermoplastic.

  19. Using Direct Metal Deposition to Fabricate Mold Plates for an Injection Mold Machine Allowing for the Evaluation of Cost Effective Near-Sourcing Opportunities in Larger, High Volume Consumer Products

    Energy Technology Data Exchange (ETDEWEB)

    Duty, Chad E [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Groh, Bill [Radio Systems Corporation, Knoxville, TN (United States)

    2014-10-31

    ORNL collaborated with Radio Systems Corporation to investigate additive manufacturing (AM) of mold plates for plastic injection molding by direct metal deposition. The team s modelling effort identified a 100% improvement in heat transfer through use of conformal cooling lines that could be built into the mold using a revolutionary design enabled by additive manufacturing. Using the newly installed laser deposition system at the ORNL Manufacturing Demonstration Facility (MDF) a stainless steel mold core was printed.

  20. Rotational Molding Process Technician. Instructional Program Package.

    Science.gov (United States)

    El Paso Community Coll., TX.

    This curriculum package contains materials developed through a partnership of the Association of Rotational Molders, El Paso Community College (Texas), and the College of DuPage (Illinois). The materials, which were developed during a 2-day DACUM (Developing a Curriculum) process, are based on national skill standards and designed for…

  1. Mechanical Properties of Injection Molded B 4C-C Ceramics

    Science.gov (United States)

    Schwetz, Karl A.; Sigl, Lorenz S.; Pfau, Lothar

    1997-10-01

    Various mechanical properties of carbon-doped boron carbide ceramics, prepared by the fabrication route, injection molding/pressureless sintering/post-hot isostatic pressing (HIP) were investigated as a function of the sintering temperature and the carbon additive level used. An optimum combination of mechanical properties (flexural stregth, fracture toughness, Young's modulus, Knoop's hardness) is thus obtained with 100% dense and very fine grained materials (mean grain size 1-4 ?m) which were sintered at temperatures from 2150 to 2175°C and post-HIPed at 2050°/200 MPa Ar, having an approximate final composition of 96 B4C-4C (wt%).

  2. Estudo de caso de peça moldada pelo processo de injeção-compressão para termoplásticos utilizando análise computacional / Study of injection-compression molded part using CAE analysis

    Scientific Electronic Library Online (English)

    Thyago M., Kiam; Nilson C., Pereira.

    2007-03-01

    Full Text Available O processamento de termoplásticos através do processo de injeção representa o principal método de fabricação de peças plásticas. Limitações do processo de injeção convencional, principalmente quanto à matéria-prima e configuração e funcionamento das máquinas disponíveis, tornam inviável a produção d [...] e produtos com grande área projetada e pequena espessura, como janelas automotivas e alguns tipos de lentes. Paralelamente, o processo de injeção evolui continuamente e há uma série de novas tecnologias geradas a partir do processo original, dentre elas o processo de injeção-compressão. No presente trabalho, utilizando análise computacional, estudou-se a produção de lentes de policarbonato através de dois processos distintos: injeção convencional e processo de injeção-compressão. A seqüência de estudos envolveu basicamente os seguintes pontos: estudo do padrão de preenchimento com conseqüente otimização do processo de injeção-compressão quanto à formação de linha de emenda; estudo da janela de processo para ambos os casos e comparação de alguns parâmetros principalmente tensão de cisalhamento e força de fechamento, por se tratarem de fatores limitantes na produção de peças com grande área projetada. Os resultados para o caso estudado comprovam grande vantagem na utilização do processo de injeção-compressão. Abstract in english The injection-molding of thermoplastics is the main process used in the production of plastics parts. There are some limitations in the conventional injection process, specially related to raw materials, machines configuration and operation, which hamper fabrication of thin parts with large areas su [...] ch as car windows and lenses. On the other hand, the process has been improved continuously with several new technologies, going beyond the conventional injection molding process, including the "injection-compression" process. In this paper, using CAE (computer aided engineering) technology, the author studied the production of PC lens by both processes: conventional injection molding and injection-compression molding. The studies were basically conducted in the following sequence: flow pattern study and optimization of the injection-compression process focusing on the weld line size, molding window study for both cases and comparison of several parameters, particularly shear stress and clamp force - as they are key parameters for the production of large-area parts. The results confirm the advantages of the injection-compression process.

  3. Versatile Molding Process for Tough Cellulose Hydrogel Materials

    OpenAIRE

    Mutsumi Kimura; Yoshie Shinohara; Junko Takizawa; Sixiao Ren; Kento Sagisaka; Yudeng Lin; Yoshiyuki Hattori; Juan P. Hinestroza

    2015-01-01

    Shape-persistent and tough cellulose hydrogels were fabricated by a stepwise solvent exchange from a homogeneous ionic liquid solution of cellulose exposure to methanol vapor. The cellulose hydrogels maintain their shapes under changing temperature, pH, and solvents. The micrometer-scale patterns on the mold were precisely transferred onto the surface of cellulose hydrogels. We also succeeded in the spinning of cellulose hydrogel fibers through a dry jet-wet spinning process. The mechanical p...

  4. Effect of the coupling agent on the properties of NdFeB injection molding magnets (abstract)

    Science.gov (United States)

    Chen, L. K.; Hung, Y. C.; Ko, W. S.

    1991-04-01

    In the manufacturing of injection molded magnets made from NdFeB (MQ) powder and nylon-12, coupling agents are normally added to prevent NdFeB powders from oxidation in the period of injection processes. The reheological behavior of NdFeB pellets related to the quantities and kinds of coupling agents. The effects of coupling agents on the NdFeB injection molded magnets are seldom presented in literature1 and will be the sub-seldom presented in the literature1 and will be the subject of this work. Five coupling agents (two belong to silane series, two belong to titanate series, and one belongs to the zircoaluminate series) have been investigated and evaluated. Differential scanning calorimetry (DSC) data show that 0.5 wt. % of isopropyle tri(dioctyl)-pyrophosphate titanate has the best result for oxidation resistance. On the other hand, the compression strength and reheological behavior of the bonded magnets are dependent on the kinds of coupling agents. The zircoaluminate coupling agent induces 30% enhancement of compression strength better than other coupling agents. Titanate coupling agents have a lower injection temperature. It demonstrated that the titanate coupling agent can effectively reduce the relative viscosity of the compounds. In the meantime, we did a 100-h environmental test at 80 °C, 90% RH. Experimental results also show that the titanate coupling agents have best anticorrosion ability. Magnetic properties of bonded magnet Br=5.7 kG, Hc=4.5 kOe, iHc=8.4 kOe, and (BH)max=6.7 mGOe can be obtained. Results suggested the titanate coupling agent is the best choice in this study.

  5. Die-sinking electrical discharge machining of a high-strength copper-based alloy for injection molds

    OpenAIRE

    F. L. Amorim; Weingaertner, W. L.

    2004-01-01

    High-strength copper alloys are used as materials for injection molding tools or as cores and inserts in steel molds because of their high thermal conductivity, corrosion and wear resistance. Unfortunately, there is little technological knowledge on the electrical discharge machining (EDM) of copper-beryllium ASTM C17200 alloy. In this work, rough and finish machining conditions were tested using copper and tungsten-copper as materials for the electrodes. Cross-sectional micrographic and hard...

  6. Implementation of Molding Constraints in Topology Optimization

    DEFF Research Database (Denmark)

    Marx, S.; Kristensen, Anders Schmidt

    2009-01-01

    In many cases the topology optimization method yield inadmissible solutions in respect to a particular manufacturing process, e.g. injection molding. In the present work it is chosen to focus on the most common injection molding parameters/factors determining the quality of the mold geometry, i.e. uniform thickness, filling of the die and ejection of the molded item, i.e. extrusion. The mentioned injection mold parameters/factors are introduced in the topology optimization by defining a centerline of the initial domain and then penalize elements in respect to the distance to the defined centerline of the domain.

  7. High numerical aperture injection-molded miniature objective for fiber-optic confocal reflectance microscopy

    Science.gov (United States)

    Chidley, Matthew Douglas

    This dissertation presents the design of a miniature injection-molded objective lens for a fiber-optic confocal reflectance microscope. This is part of an effort to demonstrate the ability to fabricate low cost, high performance biomedical optics for high resolution in vivo imaging. Disposable endoscopic microscope objectives could help in vivo confocal microscopy technology mature to enable large-scale clinical screening and detection of early cancers and pre-cancerous lesions. This five lens plastic objective has been tested as a stand-alone optical system and has been coupled to a confocal microscope for in vivo imaging of cells and tissue. Changing the spacing and rotation of the individual optical elements can compensate for fabrication inaccuracies and improve performance. An optical-bench testing system was constructed to allow interactive alignment during testing. The modulation transfer function (MTF) of the miniature objective lens is determined using the slanted-edge method. A custom MATLAB program, edgeMTF, was written to collect, analyze, and record test data. An estimated Strehl ratio of 0.64 and an MTF value of 0.70, at the fiber-optic bundle Nyquist frequency, have been obtained. The main performance limitations of the miniature objective are mechanical alignment and flow-induced birefringence. Annealing and experimental injection molding runs were conducted in effort to reduce birefringence.

  8. High-Temperature Oxidation Behavior of Two Nickel-Based Superalloys Produced by Metal Injection Molding for Aero Engine Applications

    Science.gov (United States)

    Albert, Benedikt; Völkl, Rainer; Glatzel, Uwe

    2014-09-01

    For different high-temperature applications like aero engines or turbochargers, metal injection molding (MIM) of superalloys is an interesting processing alternative. For operation at high temperatures, oxidation behavior of superalloys produced by MIM needs to match the standard of cast or forged material. The oxidation behavior of nickel-based superalloys Inconel 713 and MAR-M247 in the temperature interval from 1073 K to 1373 K (800 °C to 1100 °C) is investigated and compared to cast material. Weight gain is measured discontinuously at different oxidation temperatures and times. Analysis of oxidized samples is done via SEM and EDX-measurements. MIM samples exhibit homogeneous oxide layers with a thickness up to 4 µm. After processing by MIM, Inconel 713 exhibits lower weight gain and thinner oxide layers than MAR-M247.

  9. Solidification behavior of high-density polyethylene (HDPE) during injection molding: Correlation between crystallization kinetics and thermal gradient field

    Science.gov (United States)

    Yang, Bin; Deng, Yan-Li; Li, Gui-Jing; Miao, Ji-Bin; Xia, Ru; Qian, Jia-Sheng; Chen, Peng; Liu, Jing-Wang

    2015-07-01

    This work mainly investigated the effect of thermal field on the crystallization kinetics of high-density polyethylene (HDPE) during injection molding (IM) process. The thickness X = 0.4 was found to be a crucial location heavily influenced by thermal conduction. The temperature decay tended to be stable, with limited variation of the crystallization rate when X > 0.4. It was observed that the crystallization rate was in good proportion to the cooling rate (?). Our experimental finding showed that the consequence of relative crystallinity (?) was in agreement with that of the secondary temperature difference (STD). This study is practically significant to the further investigation on the relationship among “processing-structure-property” of polymeric materials.

  10. Heat transfer at the polymer-metal interface -- A method of analysis and its application to injection molding

    Energy Technology Data Exchange (ETDEWEB)

    Quilliet, S.; Le Bot, P.; Delaunay, D.; Jarny, Y.

    1997-07-01

    Heat transfer at the polymer-metal interface constitutes a key point to interpret shrinkage and warpage during injection molding. In heat transfer, the interface conditions are modelized by a thermal contact resistance (TCR). An apparatus was built and a new method was used to determine the TCR variation and simultaneously the temperature field in the polymer, in a real situation of injection molding. The experimental device consists in an instrumented injection mold. A specific heat flux sensor has been developed in order to determine simultaneously the metal surface temperature and the heat flux crossing the interface. The polymer surface temperature is obtained by solving numerically the heat conduction equation in the polymer. The boundary conditions are the experimental heat flux densities. The initial condition is evaluated by an inverse method based on the energy conservation and the heat flux history. Two thermal models are necessary to take into account the packing and the cooling phases. Some experimental results will be shown.

  11. Gas Atmosphere Formed in Casting by Full Mold Process

    Directory of Open Access Journals (Sweden)

    Mocek J.

    2014-10-01

    Full Text Available A test mold was designed to investigate the full mold process. Pressure changes in a gap developing between the pattern made of foamed polystyrene and the raising column of liquid alloy were determined. Studies were conducted pouring molds with cast iron and with AK11 silumin. It was found that pressure is significantly higher in the case of cast iron, due to a higher rate of pattern decomposition and more advanced dissociation of hydrocarbons. The increase in pressure was observed to have no significant effect on changes in the pouring rate as it was compensated by higher metallostatic pressure. The increase of pressure occurs immediately after the start of pouring, it reaches a maximum and then stabilizes or decreases smoothly as a result of the drop in metallostatic pressure. The temperature of pouring has a significant effect on the decomposition rate of hydrocarbons evolving from the metal. During pouring of cast iron, the presence of hydrogen was revealed. It was particularly evident across the gas-permeable coating, where the concentration has exceeded 40%. Hydrogen precipitation was accompanied by an evolution on the casting surface of considerable amounts of pyrolytic carbon. It was found that gases forming in the gap were totally free from oxygen.

  12. Recycling process of casting molds applying to precision castings

    Directory of Open Access Journals (Sweden)

    M. Drajewicz

    2012-12-01

    Full Text Available Purpose: The present work relates to investigations about the possibility of recycling and producing sinters from ceramic molds. These molds are applied for producing precise single crystal casts of nickel based superalloys to elements witch are applied to the hot section of aircraft jet engines.Design/methodology/approach: The processes of milling were carried out using the vibratory mill Herzog HSM 100H and the planetary grinder Pulverisette 7 - Fritsch Company. The measurements of all kinds of powders were conducted by using of the Kamika IPS U Analyzer and Malvern Nanosizer-ZS. To the purpose of analysis of the chemical composition an X-ray microanalysis technique was applied with the dispersion of the energy (EDS using of Thermo and Noran equipment. Findings: On the basis of examinations carried out on the powders before and after processes of milling and after processes of pressing and sintering of powders, it is possible to state that technological processes of reuse and further applying of used molds are possible. Processes of pressing were conducted applying different amounts of powders. Powders were pressed both without the addition as well as with the addition of modifiers which were added to basic powder in appropriate amounts. It was found that processes of pressing and sintering in both cases showed good results. Surfaces of pressed and sintered tablets were smooth and not-delaminated as well as did not shell.Research limitations/implications: Results will be used for future researches among others concerning the research on mechanical and thermal properties.Practical implications: Waste products and their reuse, recycling and especially consolidation of dangerous and hazardous compounds including of ceramic materials from foundry industry, will have an important place in the future on account of problems with their recycling and the storage.Originality/value: Researches on new possibilities of the application and properties of waste materials.

  13. Characteristics and infl uence factors of mold fi lling process in permanent mold with a slot gating system

    Directory of Open Access Journals (Sweden)

    Chen Changjun

    2009-11-01

    Full Text Available The main problems caused by improper gating are entrained aluminum oxide fi lms and entrapped gas. In this study, the slot gating system is employed to improve mold fi lling behavior and therefore, to improve the quality of aluminum castings produced in permanent molds. An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum fl owing into permanent molds have been developed. Graphite molds transparent to X-rays are utilized which make it possible to observe the fl ow pattern through a number of vertically oriented gating systems. The investigation discovers that there are many infl uencing factors on the mold fi lling process. This paper focuses its research on some of the factors, such as the dimensions of the vertical riser and slot thickness, as well as roughness of the coating layer. The results indicate that molten metal can smoothly fi ll into casting cavity with a proper slot gating system. A bigger vertical riser, proper slot thickness and rougher coating can provide not only a better mold fi lling pattern, but also hot melt into the top of the cavity. A proper temperature gradient is obtainable, higher at the bottom and lower at the top of the casting cavity, which is in favor of feeding during casting solidifi cation.

  14. DNA barcoding via counterstaining with AT/GC sensitive ligands in injection-molded all-polymer nanochannel devices

    DEFF Research Database (Denmark)

    Østergaard, Peter Friis; Matteucci, Marco

    2013-01-01

    Nanochannel technology, coupled with a suitable DNA labeling chemistry, is a powerful approach for performing high-throughput single-molecule mapping of genomes. Yet so far nanochannel technology has remained inaccessible to the broader research community due to high fabrication cost and/or requirement of specialized facilities/skill-sets. In this article we show that nanochannel-based mapping can be performed in all polymer chips fabricated via injection molding: a fabrication process so inexpensive that the devices can be considered disposable. Fluorescent intensity variations can be obtained from molecules extended in the polymer nanochannels via chemical counterstaining against YOYO-1. In particular, we demonstrate that the counterstaining induced fluorescent intensity variations to a large degree appear to be proportional to the theoretically computed sequence-maps of both local AT and GC variation along DNA sequences.

  15. Chemical vapor deposition and analysis of thermally insulating ZrO{sub 2} layers on injection molds

    Energy Technology Data Exchange (ETDEWEB)

    Atakan, Burak; Khlopyanova, Victoria; Mausberg, Simon; Kandzia, Adrian; Pflitsch, Christian [Thermodynamik (IVG) and Cenide, Universitaet Duisburg-Essen, Lotharstr. 1, 47057 Duisburg (Germany); Mumme, Frank [Kunststoff-Institut Luedenscheid, Karolinenstrasse 8, 58507 Luedenscheid (Germany)

    2015-07-15

    High quality injection molding requires a precise control of cooling rates. Thermal barrier coating (TBC) of zirconia with a thickness of 20-40 ?m on polished stainless steel molds could provide the necessary insulating effect. This paper presents results of zirconia deposition on stainless steel substrates using chemical vapor deposition (CVD) aiming to provide the process parameters for the deposition of uniform zirconia films with such a thickness. The deposition was performed with zirconium (IV) acetylacetonate (Zr(C{sub 5}H{sub 7}O{sub 2}){sub 4}) as precursor and synthetic air as co-reactant, which allows deposition at temperatures below 600 C. The experiments were carried out in a hot-wall reactor at pressures between 7.5 mbar and 500 mbar and in a temperature range from 450 C to 600 C. Important growth parameters were characterized and growth rates between 1 and 2.5 ?m/h were achieved. Thick and well adhering zirconia layers of 38 ?m could be produced on steel within 40 h. The transient heat transfer rate upon contact with a hot surface was also evaluated experimentally with the thickest coatings. These exhibit a good TBC performance. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Shear controlled alignment of short carbon fibers in copper matrix composite green samples produced by powder injection molding

    Science.gov (United States)

    Shirazi, Irfan; Ahmad, Faiz; Raza, M. Rafi; Muhsan, Ali. S.; Aslam, M.

    2015-07-01

    The tensile properties of short fiber reinforced composites are enhanced if fiber alignment in the load direction is achieved. Powder injection molding provides partial alignment of fibers in molded parts and shows a skin-core effect. The objective of this study was to align fibers completely in flow direction and reducing skin-core effect in green samples. This objective was achieved by changing the type of flow during molding by changing sprue geometry in a way that diverging flow is developed in it. This diverging flow was converted to converging flow when feedstock entered mold cavity and generated shear to align fibers. This sprue modification was helpful in aligning short fibers in flow direction and eliminating skin-core effect.

  17. Influence of mold and substrate material combinations on nanoimprint lithography process: MD simulation approach

    Science.gov (United States)

    Yang, Seunghwa; Yu, Suyoung; Cho, Maenghyo

    2014-05-01

    A molecular dynamics (MD) study was performed to examine the effect of mold-substrate material composition on the pattern transferring and defects of the resist polymer in a thermal Nano Imprint Lithography (NIL) process. As candidate materials, single crystalline nickel (Ni), silicon (Si) and silica (SiO2, ?-quartz) for the rigid mold substrate, and amorphous poly-(methylmethacrylate) (PMMA) thin film for the resist were considered for common applications in NIL processes. Three different material compositions of Si mold-Ni substrate, Ni mold-Si substrate, and quartz mold-Ni substrate were considered. In accordance with a real NIL process, a sequence of indentation-relaxation-release processes was quasi-statically simulated using isothermal ensemble simulation on tri-layer molecular structures consisting of a mold, resist, and substrate. To correlate the deformed shape and delamination of PMMA resist from the substrate in indentation and release processes, non-bond interaction energy between a rigid mold and resist was calculated for each combination of mold and substrate materials. The Si mold-Ni substrate combination shows successful pattern transfer to the resist polymer even without an anti-sticking layer as a result of the desirable balance of surface free energy for mold and substrate materials. However, Ni mold-Si substrate combination shows a critical delamination of the resist in the release process due to strong van der Waals adhesion between the resist and Ni mold. Similarly, the quartz mold-Ni substrate combination shows the same delamination in pattern transfer, but the adhesion of the resist to the quartz mold is attributed to electrostatic interaction. In order to provide guidelines for material selection in imprint-like processes where surface adsorption and wetting characteristics are critical design parameters, a simple PMMA-rigid plate model is proposed, with which consistent surface interaction characteristics in the full model NIL process simulation can be obtained.

  18. Oxide Formation In Metal Injection Molding Of 316L Stainless Steel

    Directory of Open Access Journals (Sweden)

    Jang Jin Man

    2015-06-01

    Full Text Available The effects of sintering condition and powder size on the microstructure of MIMed parts were investigated using water-atomized 316L stainless steel powder. The 316L stainless steel feedstock was injected into micro mold with micro features of various shapes and dimensions. The green parts were debound and pre-sintered at 800°C in hydrogen atmosphere and then sintered at 1300°C and 1350°C in argon atmosphere of 5torr and 760torr, respectively. The oxide particles were formed and distributed homogeneously inside the sample except for the outermost region regardless of sintering condition and powder size. The width of layer without oxide particles are increased with decrease of sintering atmosphere pressure and powder size. The fine oxides act as the obstacle on grain growth and the high sintering temperature causes severe grain growth in micro features due to larger amount of heat gain than that in macro ones.

  19. Microstructure and magnetic properties of Fe-50%Ni alloy fabricated by powder injection molding

    Science.gov (United States)

    Ma, Jidong; Qin, Mingli; Zhang, Lin; Zhang, Ruijie; Qu, Xuanhui

    2013-03-01

    Fe-50%Ni soft magnetic alloys were produced by powder injection molding using carbonyl iron and carbonyl nickel as raw materials. The effects of sintering temperature and time on the microstructure and magnetic properties of the alloys were investigated. The results indicate that the magnetic properties are dependent on the microstructure. The densification and grain size of the alloys increase with increasing sintering temperature and time, facilitating the enhancement of permeability and saturation induction, as well as the decrease of coercive force. In the case of the sintering temperature of 1360 °C for 10 h, the relative density of 97% and grain size of 200 ?m were obtained, and the maximum permeability of 43,541, saturation induction of 1.48 T and coercive force of 6.8 A/m were achieved. Further elongation of sintering time did not bring about any increase of densification and grain size.

  20. Qualification Methods of Al2O3 Injection Molding Raw Materials

    Science.gov (United States)

    Egész, Á.; Gömze, L. A.

    2015-04-01

    For producing ceramic arc tube parts (plugs), there are used two different major components for producing injection molding raw material (feedstock): high purity alumina powder as the main component, and an organic paraffin wax as a binder material. It is expressly important to know the material, physical and chemical properties of these components, since mainly these have effect on the homogenity of feedstock, and therefore on the quality of end product. In this research, both of the main components and the moldable raw material was investigated by visual, physical, and thermal methods. As most important and main statement, the researchers found that the dynamic viscosity of raw material depends more on the applied temperature, than on the deformation speed gradient. Applied analitycal methods were laser granulometry, sieve analysis, differential thermal analysis and rheology analysis.

  1. Injection molded chips with integrated conducting polymer electrodes for electroporation of cells

    DEFF Research Database (Denmark)

    Andresen, Kristian; Hansen, Morten

    2010-01-01

    We present the design-concept for an all polymer injection molded single use microfluidic device. The fabricated devices comprise integrated conducting polymer electrodes and Luer fitting ports to allow for liquid and electrical access. A case study of low voltage electroporation of biological cells in suspension is presented. The working principle of the electroporation device is based on a focusing of the electric field by means of a constriction in the flow channel for the cells. We demonstrate the use of AC voltage for electroporation by applying a 1 kHz, +/- 50 V square pulse train to the electrodes and show delivery of polynucleotide fluorescent dye in 46% of human acute monocytic leukemia cells passing the constriction.

  2. INJECTION MOLDING AND STRUCTURAL ANALYSIS IN METAL TO PLASTIC CONVERSION OF BOLTED FLANGE JOINT BY CAE

    Directory of Open Access Journals (Sweden)

    Marian Blaško

    2014-12-01

    Full Text Available Many metal parts in various applications are being replaced by plastic parts. There are several reasons for that depending on actual application - minimize part cost, enhance corrosion resistance, integrating more components into one part etc. Most important steps of metal to plastic conversion are material selection and design of plastic part. Plastic part has to withstand the same load as metal part. To fulfill this requirement fiber reinforced engineering plastics are often used. Also it is convenient to substitute heavy wall sections with ribbed structure to increase load-carrying ability of part and decrease cycle time, eliminate voids, sink marks etc. Mechanical properties of such part could be highly affected by fiber orientation. Results of fiber orientation from injection molding filling analysis can be used in stress analysis for better prediction of part response to mechanical load. Such coupled analysis is performed here in this case study on bolted flange joint.

  3. Biodegradability of injection molded bioplastic pots containing polylactic acid and poultry feather fiber.

    Science.gov (United States)

    Ahn, H K; Huda, M S; Smith, M C; Mulbry, W; Schmidt, W F; Reeves, J B

    2011-04-01

    The biodegradability of three types of bioplastic pots was evaluated by measuring carbon dioxide produced from lab-scale compost reactors containing mixtures of pot fragments and compost inoculum held at 58 °C for 60 days. Biodegradability of pot type A (composed of 100% polylactic acid (PLA)) was very low (13 ± 3%) compared to literature values for other PLA materials. Near infrared spectroscopy (NIRS) results suggest that the PLA undergoes chemical structural changes during polymer extrusion and injection molding. These changes may be the basis of the low biodegradability value. Biodegradability of pot types B (containing 5% poultry feather, 80% PLA, 15% starch), and C (containing 50% poultry feather, 25% urea, 25% glycerol), were 53 ± 2% and 39 ± 3%, respectively. More than 85% of the total biodegradation of these bioplastics occurred within 38 days. NIRS results revealed that poultry feather was not degraded during composting. PMID:21320772

  4. Injection molded chips with integrated conducting polymer electrodes for electroporation of cells

    Science.gov (United States)

    Ødegaard Andresen, Kristian; Hansen, Morten; Matschuk, Maria; Terpager Jepsen, Søren; Schiøtt Sørensen, Henrik; Utko, Pawel; Selmeczi, Dávid; Hansen, Thomas S.; Larsen, Niels B.; Rozlosnik, Noemi; Taboryski, Rafael

    2010-05-01

    We present the design-concept for an all polymer injection molded single use microfluidic device. The fabricated devices comprise integrated conducting polymer electrodes and Luer fitting ports to allow for liquid and electrical access. A case study of low voltage electroporation of biological cells in suspension is presented. The working principle of the electroporation device is based on a focusing of the electric field by means of a constriction in the flow channel for the cells. We demonstrate the use of AC voltage for electroporation by applying a 1 kHz, ±50 V square pulse train to the electrodes and show delivery of polynucleotide fluorescent dye in 46% of human acute monocytic leukemia cells passing the constriction.

  5. Injection molded chips with integrated conducting polymer electrodes for electroporation of cells

    International Nuclear Information System (INIS)

    We present the design-concept for an all polymer injection molded single use microfluidic device. The fabricated devices comprise integrated conducting polymer electrodes and Luer fitting ports to allow for liquid and electrical access. A case study of low voltage electroporation of biological cells in suspension is presented. The working principle of the electroporation device is based on a focusing of the electric field by means of a constriction in the flow channel for the cells. We demonstrate the use of AC voltage for electroporation by applying a 1 kHz, ±50 V square pulse train to the electrodes and show delivery of polynucleotide fluorescent dye in 46% of human acute monocytic leukemia cells passing the constriction.

  6. Research on properties of carbon black/polypropylene composites by dynamic injection molding

    Science.gov (United States)

    Wu, Ming-Chun; He, Guang-Jian; Huang, Zhao-Xia; Zhou, Li-Ying; He, He-Zhi

    2016-03-01

    Polymer composites filled with conductive carbon black (CB) are gaining popularity for electromagnetic shielding applications. Dynamic injection molding method was adopted to study the influences of vibration force field on electrical properties of polypropylene/CB composites. The results showed that the percolation phenomenon of conductivity of composites occurred at 15wt% and the calculated SE was positive correlated with the variation trend of conductivity. The calculated SE of composite was more than 30dB at a CB concentration of 30wt%, which could obtain good shielding effects. The result could offer optimum vibration parameters for producing electromagnetic shielding composites by respectively changing the amplitudes and frequencies of the vibration force field.

  7. Process for cross-linking vinyl chloride resin moldings

    International Nuclear Information System (INIS)

    An impregnation process for radiation cross-linking polymerization is improved by the utilization of a mixed solution of special monomers. This mixed solution consists of single functional substances containing as main ingredients at least one monomer selected from the group of methyl acrylate, ethyl acrylate, methyl methacrylate, styrene, alpha methyl styrene etc., and multiple functional substances soluble in the above single functional substances. With this mixture polyvinyl resin moldings are impregnated to undergo irradiation with high energy radiations for cross-linking. Under such conditions, the mechanical properties and the heat resisting properties which could not be obtained in the conventional process of vinyl chloride resin moldings are improved. In embodiments, polyvinyl chloride in the form of sole polymers, copolymers and graft-polymers can be used, if they do not dissolve in the single functional monomers. The period of impregnation time depends upon the thickness of the moldings and is adjustable to the fabrication of a plastic composite for cross-linking only its surface portions. The irradiation can be effected in air under normal temperature and pressure. The radiation doses are limited to the range between the formation of cross-linking and the deterioration of polymers, generally 105-107 rads. In one example, a sheet 1 mm thick produced by rolling vinyl chloride resin compositions was impregnated with a mixed solution of methyl methacrylate and ethylene glycol dimethacrylate in various blending proportions. After impregnation, the sheet was irradiated by a Cockcroft electron accelerator in air at 200C with 5 x 106 rads. (Iwakiri, K.)

  8. Image-guided tissue engineering of anatomically shaped implants via MRI and micro-CT using injection molding.

    Science.gov (United States)

    Ballyns, Jeffery J; Gleghorn, Jason P; Niebrzydowski, Vicki; Rawlinson, Jeremy J; Potter, Hollis G; Maher, Suzanne A; Wright, Timothy M; Bonassar, Lawrence J

    2008-07-01

    This study demonstrates for the first time the development of engineered tissues based on anatomic geometries derived from widely used medical imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI). Computer-aided design and tissue injection molding techniques have demonstrated the ability to generate living implants of complex geometry. Due to its complex geometry, the meniscus of the knee was used as an example of this technique's capabilities. MRI and microcomputed tomography (microCT) were used to design custom-printed molds that enabled the generation of anatomically shaped constructs that retained shape throughout 8 weeks of culture. Engineered constructs showed progressive tissue formation indicated by increases in extracellular matrix content and mechanical properties. The paradigm of interfacing tissue injection molding technology can be applied to other medical imaging techniques that render 3D models of anatomy, demonstrating the potential to apply the current technique to engineering of many tissues and organs. PMID:18593357

  9. Development of homogeneous filling method of particulate materials into compression mold for nuclear fuel process

    International Nuclear Information System (INIS)

    In order to improve the production technology of mixed oxide of plutonium and uranium (MOX) pellets for Fast Breeder Reactor (FBR), the applicability of particle simulation to optimize mold-filling process, instead of trial and error experiments, was investigated. The mold-filling simulation was prepared employing large scale Distinct Element Method (DEM), which has been developed in powder technology. The DEM simulation was conducted using physical properties of tungsten trioxide (WO3) granules, which are model of MOX granules, and compared with results of mold-filling experiments with WO3 granules. The simulation could well represent the mold-filling behavior, and estimate the degree of segregation in the mold. It was found that the segregation in feeding container and the flow behavior of granules filled into the mold influences much on the packed structure of granules in the mold. The DEM is expected to be a powerful tool to optimize MOX fuel production process. (author)

  10. CONVERSION OF WIND POWER TO HYDROGEN FUEL: DESIGN OF AN ALTERNATIVE ENERGY SYSTEM FOR AN INJECTION MOLDING FACILITY

    Science.gov (United States)

    Injection molding plants are large consumers of electricity. At its current level of operations, Harbec Plastics (Ontario, NY) uses about 2,000,000 kilowatt-hours of electricity per year. Based on the US average fuel mix, approximately 1.5 pounds of CO2

  11. Optimization of powder injection molding of feedstock based on aluminum oxide and multicomponent water-soluble polymer binder.

    Czech Academy of Sciences Publication Activity Database

    Hausnerová, B.; Marcaníková, L.; Filip, Petr; Sáha, P.

    2011-01-01

    Ro?. 51, ?. 7 (2011), s. 1376-1382. ISSN 0032-3888 R&D Projects: GA ?R GA103/08/1307 Institutional research plan: CEZ:AV0Z20600510 Keywords : powder injection mold ing * viscosity * thermogravimetric analysis Subject RIV: BK - Fluid Dynamics Impact factor: 1.302, year: 2011

  12. Hybrid tooling technologies and standardization for the manufacturing of inserts for micro injection molding

    DEFF Research Database (Denmark)

    Tosello, Guido; Fillon, Bertrand

    2007-01-01

    This paper is based on the European Platform’s activities within the 4M Network of Excellence “Multi-Material Micro Manufacturing”. To overpass limitations of the current existing micro tooling capabilities, a new generation of micro hybrid tooling technologies for micro replication was developed. A metrological approach was applied to standardize the employed tooling processes (micro milling, µEDM, laser micromachining, electrochemical µ-milling). The micro tools were then tested with different polymers (PP, PP + nano fillers, PC, COC). The paper provides a comparison of these technologies concerning obtainable feature sizes, surface finish, and aspect ratios of both micro tools and micro molded parts.

  13. Research of thermal response simulation and mold structure optimization for rapid heat cycle molding processes, respectively, with steam heating and electric heating

    International Nuclear Information System (INIS)

    The dynamic mold temperature control system is the key of rapid heat cycle molding (RHCM) technology because it significantly affects the stability of the process, productivity and the quality of the final polymer part. For this reason, the approaches and techniques for dynamic mold temperature control were discussed in this study and two different dynamic mold temperature control methods, respectively, with steam heating and electric heating were found to be very feasible in mass production. The methods and principles of mold design for the two RHCM technologies were also discussed and then several different kinds of mold structures were designed. By constructing the corresponding thermal response analytical models for these RHCM molds, the temperature responses of the molding systems in the heating and cooling process of RHCM were simulated and studied. The effects of the mold design parameters such as the insulation layer between mold plate and mold inert, and mold material, on thermal response efficiency and temperature uniformity of the two RHCM processes were analyzed based on the simulation results. The results show that the insulation layer can increase the upper limit temperature of RHCM with steam heating and improve the heating speed of RHCM with electric heating. It can also greatly decrease the energy consumption of the two RHCM processes. The heating efficiency of RHCM with steam heating can be effectively improved by increasing the thermal conductivity of the cavity/core material, while the situation is diametrically opposite for RHCM with electric heating. Therefore, we acquired an optimized mold design principle and method for RHCM with steam heating and electric heating, respectively. Finally, a new electric heating mold with a cooling plate was proposed to enhance the cooling efficiency. The thermal response of this new electric heating mold was also simulated. The simulation results show that the cooling plate can significantly improve the cooling and heating efficiency.

  14. MECHANICAL PROPERTIES OF INJECTION-MOLDED FOAMED WHEAT STRAW FILLED HDPE BIOCOMPOSITES: THE EFFECTS OF FILLER LOADING AND COUPLING AGENT CONTENTS

    Directory of Open Access Journals (Sweden)

    Fatih Mengeloglu,

    2012-06-01

    Full Text Available This study investigated the effect of filler loading and coupling agent contents on the densities and mechanical properties of injection-molded foamed biocomposites. Biocomposite pellets were manufactured using wheat straw flour, maleic anhydrite grafted polyethylene (MAPE, paraffin wax, and high-density polyethylene (HDPE with an extrusion process. Pellets and the chemical foaming agent (azodicarbonamide were dry-mixed and foamed in an injection-molding machine. Densities and mechanical properties of the foamed biocomposites samples were measured and analyzed using central composite design (CCD. The results showed that both filler loading and coupling agent contents affected the density and mechanical properties of foamed biocomposites. Densities in the range of 0.57 to 0.81 gr cm-3 were achieved. Best results were obtained when less than 20% wheat straw flour and 1% coupling agent content were used. The flexural modulus and tensile modulus of foamed biocomposites were improved with increasing filler loading. However, flexural strength, tensile strength, elongation at break, and impact strength values were diminished. The tensile strength of the biocomposites was positively affected by CA contents, but other mechanical properties were not affected by it. Overall, injection molded foamed biocomposites with moderate mechanical properties were produced.

  15. Modeling of process-induced residual stresses and resin flow behavior in resin transfer molded composites with woven fiber mats

    Science.gov (United States)

    Golestanian, Hossein

    This research focuses on modeling Resin Transfer Molding process for manufacture of composite parts with woven fiber mats. Models are developed to determine cure dependent stiffness matrices for composites manufactured with two types of woven fiber mats. Five-harness carbon and eight-harness fiberglass mats with EPON 826 resin composites are considered. The models presented here take into account important material/process parameters with emphasis on; (1) The effects of cure-dependent resin mechanical properties, (2) Fiber undulation due to the weave of the fiber fill and warp bundles, and (3) Resin interaction with the fiber bundles at a microscopic scale. Cure-dependent mechanical properties were then used in numerical models to determine residual stresses and deformation in the composite parts. The complete cure cycle was modeled in these analyses. Also the cool down stage after the composite cure was analyzed. The effect of 5% resin shrinkage on residual stresses and deformations was also investigated. In the second part of the study, Finite Element models were developed to simulate mold filling in RTM processes. Resin flow in the fiber mats was modeled as flow through porous media. Physical models were also developed to investigate resin flow behavior into molds of rectangular and irregular shapes. Silicone fluids of 50 and 100 centistoke viscosities as well as EPON 826 epoxy resin were used in the mold filling experiments. The reinforcements consisted of several layers of woven fiberglass and carbon fiber mats. The effects of injection pressure, fluid viscosity, type of reinforcement, and mold geometry on mold filling times were investigated. Fiber mat permeabilities were determined experimentally for both types of reinforcements. Comparison of experimental and numerical resin front positions indicated the importance of edge effects in resin flow behavior in small cavities. The resin front positions agreed well for the rectangular mold geometry.

  16. Versatile Molding Process for Tough Cellulose Hydrogel Materials

    Science.gov (United States)

    Kimura, Mutsumi; Shinohara, Yoshie; Takizawa, Junko; Ren, Sixiao; Sagisaka, Kento; Lin, Yudeng; Hattori, Yoshiyuki; Hinestroza, Juan P.

    2015-11-01

    Shape-persistent and tough cellulose hydrogels were fabricated by a stepwise solvent exchange from a homogeneous ionic liquid solution of cellulose exposure to methanol vapor. The cellulose hydrogels maintain their shapes under changing temperature, pH, and solvents. The micrometer-scale patterns on the mold were precisely transferred onto the surface of cellulose hydrogels. We also succeeded in the spinning of cellulose hydrogel fibers through a dry jet-wet spinning process. The mechanical property of regenerated cellulose fibers improved by the drawing of cellulose hydrogel fibers during the spinning process. This approach for the fabrication of tough cellulose hydrogels is a major advance in the fabrication of cellulose-based structures with defined shapes.

  17. Versatile Molding Process for Tough Cellulose Hydrogel Materials.

    Science.gov (United States)

    Kimura, Mutsumi; Shinohara, Yoshie; Takizawa, Junko; Ren, Sixiao; Sagisaka, Kento; Lin, Yudeng; Hattori, Yoshiyuki; Hinestroza, Juan P

    2015-01-01

    Shape-persistent and tough cellulose hydrogels were fabricated by a stepwise solvent exchange from a homogeneous ionic liquid solution of cellulose exposure to methanol vapor. The cellulose hydrogels maintain their shapes under changing temperature, pH, and solvents. The micrometer-scale patterns on the mold were precisely transferred onto the surface of cellulose hydrogels. We also succeeded in the spinning of cellulose hydrogel fibers through a dry jet-wet spinning process. The mechanical property of regenerated cellulose fibers improved by the drawing of cellulose hydrogel fibers during the spinning process. This approach for the fabrication of tough cellulose hydrogels is a major advance in the fabrication of cellulose-based structures with defined shapes. PMID:26537533

  18. Index change of chalcogenide materials from precision glass molding processes

    Science.gov (United States)

    Deegan, J.; Walsh, K.; Lindberg, G.; Benson, R.; Gibson, D.; Bayya, S.; Sanghera, J.; Stover, E.

    2015-05-01

    With the increase in demand for infrared optics for thermal applications and the use of glass molding of chalcogenide materials to support these higher volume optical designs, an investigation of changes to the optical properties of these materials is required. Typical precision glass molding requires specific thermal conditions for proper lens molding of any type of optical glass. With these conditions a change (reduction) of optical index occurs after molding of all oxide glass types and it is presumed that a similar behavior will happen with chalcogenide based materials. We will discuss the effects of a typical molding thermal cycle for use with commercially and newly developed chalcogenide materials and show results of index variation from nominally established material data.

  19. Survey of molds, yeast and Alicyclobacillus spp. from a concentrated apple juice productive process

    OpenAIRE

    Beatriz de Cássia Martins Salomão; Chalana Muller; Hudson Couto do Amparo; Gláucia Maria Falcão de Aragão

    2014-01-01

    Bacteria and molds may spoil and/or contaminate apple juice either by direct microbial action or indirectly by the uptake of metabolites as off-flavours and toxins. Some of these microorganisms and/or metabolites may remain in the food even after extensive procedures. This study aim to identify the presence of molds (including heat resistant species) and Alicyclobacillus spp., during concentrated apple juice processing. Molds were isolated at different steps and then identified by their macro...

  20. Determinação da redução da resistência à tração em corpos de prova com Weld Line / Determination of reduction of the weld line strength in injection molded

    Scientific Electronic Library Online (English)

    R.P., Bom; A.F., Kalin.

    2008-06-01

    Full Text Available Neste trabalho objetivou-se determinar a redução da resistência à tração de corpos de prova com linhas de solda. Os corpos de prova ASTM foram moldados pelo processo de injeção com diferentes temperaturas de plastificação (180 ºC a 280 ºC). O material utilizado foi o polímero termoplástico Polystyro [...] l 158 K da Basf. Este estudo relaciona as linhas de solda em produtos moldados por injeção com a redução da resistência mecânica devido a fragilização na região da linha de solda. Para o desenvolvimento deste trabalho foi projetado e desenvolvido um molde de injeção com uma cavidade em forma de corpo de prova com canal de ataque pelas extremidades. Desta forma no momento da junção dos fluxos obtêm-se uma linha de solda no centro do corpo de prova. Os parâmetros do processo de injeção foram determinados a partir de um aplicativo comercial. A temperatura do molde e o tempo de injeção permaneceram constantes. O tempo de solidificação do material foi determinado analiticamente, considerando-se o centro do corpo de prova como referência. Foram injetados dez corpos de prova em cada uma das temperaturas. Foi observada de forma clara a existência de linhas de junção no centro da peça e as condições de processo utilizadas não permitiram a formação de linha de solda fria. Após a realização dos ensaios de tração, foi determinado que a tensão de ruptura decresce nas seguintes condições: com a diminuição da temperatura de injeção e do tempo de solidificação e com o aumento da trinca. A ruptura sempre ocorreu na linha de solda. Abstract in english In this paper, the purpose is to determine the weld line strength in injection molded samples. The ASTM standard dogbone-shaped samples were molded over a range of melt temperatures (180 ºC up to 280 ºC). The plastic used was a commercial grade of polystyrene (PS), BASF Polystyrol 158K. This study l [...] inks weld lines in parts by injection molding with mechanical strength reduction due to embrittling effect in weld-line region. A single-cavity mold double-gated was used to generate ASTM D638 Type I tensile specimens. The double-gated and runner allow the parts to be molded with weld line. The injection process parameters were determined by imputing resin, machine and geometry information into a CAE software package. The mold temperature and fill time were maintaining the same. The frozen time was determined by analytic equation, which considers the center of the thickness as reference. For each melt temperature 10 samples were tested. The weld line was clearly noted in the centre of the samples and the process condition set avoided the cold weld line. By the strength tests were possible to realize that lower the injection temperature lower the frozen time and higher the length of the crack. Then low injection temperature leads to low maximum strength. The fracture always occurs in the weld line.

  1. Fabrication and characterization of injection molded poly ({epsilon}-caprolactone) and poly ({epsilon}-caprolactone)/hydroxyapatite scaffolds for tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Cui Zhixiang [Zhengzhou University, Henan (China); Nelson, Brenton; Peng, YiYan [University of Wisconsin-Madison, Wisconsin (United States); Li Ke [South China University of Technology, Guangzhou (China); Pilla, Srikanth; Li Wanju [University of Wisconsin-Madison, Wisconsin (United States); Turng, Lih-Sheng, E-mail: turng@engr.wisc.edu [University of Wisconsin-Madison, Wisconsin (United States); South China University of Technology, Guangzhou (China); Huazhong University of Science of Technology, Wuhan (China); Shen Changyu, E-mail: shency@zzu.edu.cn [Zhengzhou University, Henan (China)

    2012-08-01

    In this study, poly({epsilon}-caprolactone) (PCL)/sodium chloride (NaCl), PCL/poly(ethylene oxide) (PEO)/NaCl and PCL/PEO/NaCl/hydroxyapatite (HA) composites were injection molded and characterized. The water soluble and sacrificial polymer, PEO, and NaCl particulates in the composites were leached by deionized water to produce porous and interconnected microstructures. The effect of leaching time on porosity, and residual contents of NaCl and NaCl/HA, as well as the effect of HA addition on mechanical properties was investigated. In addition, the biocompatibility was observed via seeding human mesenchymal stem cells (hMSCs) on PCL and PCL/HA scaffolds. The results showed that the leaching time depends on the spatial distribution of sacrificial PEO phase and NaCl particulates. The addition of HA has significantly improved the elastic (E Prime ) and loss moduli (E Double-Prime ) of PCL/HA scaffolds. Human MSCs were observed to have attached and proliferated on both PCL and PCL/HA scaffolds. Taken together, the molded PCL and PCL/HA scaffolds could be good candidates as tissue engineering scaffolds. Additionally, injection molding would be a potential and high throughput technology to fabricate tissue scaffolds. - Highlights: Black-Right-Pointing-Pointer PCL/NaCl, PCL/PEO/NaCl and PCL/PEO/NaCl/HA composites were injection molded. Black-Right-Pointing-Pointer Leaching time depends on the distribution of PEO phase and NaCl particulates. Black-Right-Pointing-Pointer The elastic and loss moduli of PCL/HA scaffolds have significantly improved. Black-Right-Pointing-Pointer Human hMSCs have attached, survived and proliferated well on PCL and PCL/HA scaffolds. Black-Right-Pointing-Pointer Molded PCL and PCL/HA scaffolds could be good candidates for tissue engineering.

  2. Fabrication and characterization of injection molded poly (?-caprolactone) and poly (?-caprolactone)/hydroxyapatite scaffolds for tissue engineering

    International Nuclear Information System (INIS)

    In this study, poly(?-caprolactone) (PCL)/sodium chloride (NaCl), PCL/poly(ethylene oxide) (PEO)/NaCl and PCL/PEO/NaCl/hydroxyapatite (HA) composites were injection molded and characterized. The water soluble and sacrificial polymer, PEO, and NaCl particulates in the composites were leached by deionized water to produce porous and interconnected microstructures. The effect of leaching time on porosity, and residual contents of NaCl and NaCl/HA, as well as the effect of HA addition on mechanical properties was investigated. In addition, the biocompatibility was observed via seeding human mesenchymal stem cells (hMSCs) on PCL and PCL/HA scaffolds. The results showed that the leaching time depends on the spatial distribution of sacrificial PEO phase and NaCl particulates. The addition of HA has significantly improved the elastic (E?) and loss moduli (E?) of PCL/HA scaffolds. Human MSCs were observed to have attached and proliferated on both PCL and PCL/HA scaffolds. Taken together, the molded PCL and PCL/HA scaffolds could be good candidates as tissue engineering scaffolds. Additionally, injection molding would be a potential and high throughput technology to fabricate tissue scaffolds. - Highlights: ?PCL/NaCl, PCL/PEO/NaCl and PCL/PEO/NaCl/HA composites were injection molded. ?Leaching time depends on the distribution of PEO phase and NaCl particulates. ?The elastic and loss moduli of PCL/HA scaffolds have significantly improved. ?Human hMSCs have attached, survived and proliferated well on PCL and PCL/HA scaffolds. ?Molded PCL and PCL/HA scaffolds could be good candidates for tissue engineering.

  3. Thermal shock behavior of tungsten based alloys manufactured via powder injection molding

    Energy Technology Data Exchange (ETDEWEB)

    Pintsuk, G., E-mail: g.pintsuk@fz-juelich.de [Forschungszentrum Jülich, EURATOM-Association, D-52425 Jülich (Germany); Blagoeva, D. [Nuclear Research and Consultancy Group, P.O. Box 25, 1755 ZG Petten (Netherlands); Opschoor, J. [ECN, Energy research Centre of the Netherlands, P.O. Box 1, 1755 ZG Petten (Netherlands)

    2013-11-15

    The focus of this work is to address mechanical strength and recrystallization resistance through thermal shock investigation of newly developed fine grained tungsten base materials (i.e., pure tungsten and two doped tungsten-grades incorporating either 1 or 5 vol%Y{sub 2}O{sub 3} produced via powder injection molding (PIM)). Therefore, repetitive ELM (edge localized mode)-like loads (n = 100) were applied by means of an electron beam at various temperatures between RT and 400 °C (673 K) with a pulse duration of 1 ms and an absorbed power density of up to 1.13 GW/m{sup 2}. The microstructural properties, e.g. grain size, and Y{sub 2}O{sub 3}-particle distribution, were correlated with crack formation at a certain temperature, the crack propagation direction towards the bulk material and the amount of plastic deformation/surface roughening at higher temperatures. Thereby, it was shown that W–1 vol%Y{sub 2}O{sub 3} outperformed all other investigated grades and reference materials from literature.

  4. Thermal shock behavior of tungsten based alloys manufactured via powder injection molding

    Energy Technology Data Exchange (ETDEWEB)

    Pintsuk, G. [Forschungszentrum Juelich, EURATOM-Association, D-52425 Juelich (Germany); Blagoeva, D. Nuclear Research and Consultancy Group NRG, PO Box 25, 1755 ZG Petten (Netherlands)); Opschoor, J. [Energy research Centre of the Netherlands ECN, P.O. Box 1, 1755 ZG Petten (Netherlands)

    2013-11-15

    The focus of this work is to address mechanical strength and recrystallization resistance through thermal shock investigation of newly developed fine grained tungsten base materials (i.e., pure tungsten and two doped tungsten-grades incorporating either 1 or 5 vol%Y2O3 produced via powder injection molding (PIM)). Therefore, repetitive ELM (edge localized mode)-like loads (n = 100) were applied by means of an electron beam at various temperatures between RT and 400C (673 K) with a pulse duration of 1 ms and an absorbed power density of up to 1.13 GW/m{sup 2}. The microstructural properties, e.g. grain size, and Y2O3-particle distribution, were correlated with crack formation at a certain temperature, the crack propagation direction towards the bulk material and the amount of plastic deformation/surface roughening at higher temperatures. Thereby, it was shown that W-1 vol%Y2O3 outperformed all other investigated grades and reference materials from literature.

  5. Injection molding of ceramic filled polypropylene: The effect of thermal conductivity and cooling rate on crystallinity

    Energy Technology Data Exchange (ETDEWEB)

    Suplicz, A.; Szabo, F.; Kovacs, J.G., E-mail: kovacs@pt.bme.hu

    2013-12-20

    Highlights: • BN, talc and TiO{sub 2} in 30 vol% were compounded with polypropylene matrix. • According to the DSC measurements, the fillers are good nucleating agents. • The thermal conductivity of the fillers influences the cooling rate of the melt. • The higher the cooling rate is, the lower the crystallinity in the polymer matrix. - Abstract: Three different nano- and micro-sized ceramic powders (boron-nitride (BN), talc and titanium-dioxide (TiO{sub 2})) in 30 vol% have been compounded with a polypropylene (PP) matrix. Scanning electron microscopy (SEM) shows that the particles are dispersed smoothly in the matrix and larger aggregates cannot be discovered. The cooling gradients and the cooling rate in the injection-molded samples were estimated with numerical simulations and finite element analysis software. It was proved with differential scanning calorimetry (DSC) measurements that the cooling rate has significant influence on the crystallinity of the compounds. At a low cooling rate BN works as a nucleating agent so the crystallinity of the compound is higher than that of unfilled PP. On the other hand, at a high cooling rate, the crystallinity of the compound is lower than that of unfilled PP because of its higher thermal conductivity. The higher the thermal conductivity is, the higher the real cooling rate in the material, which influences the crystallization kinetics significantly.

  6. Ceramic micro-injection molded nozzles for serial femtosecond crystallography sample delivery

    Science.gov (United States)

    Beyerlein, K. R.; Adriano, L.; Heymann, M.; Kirian, R.; Knoška, J.; Wilde, F.; Chapman, H. N.; Bajt, S.

    2015-12-01

    Serial femtosecond crystallography (SFX) using X-ray Free-Electron Lasers (XFELs) allows for room temperature protein structure determination without evidence of conventional radiation damage. In this method, a liquid suspension of protein microcrystals can be delivered to the X-ray beam in vacuum as a micro-jet, which replenishes the crystals at a rate that exceeds the current XFEL pulse repetition rate. Gas dynamic virtual nozzles produce the required micrometer-sized streams by the focusing action of a coaxial sheath gas and have been shown to be effective for SFX experiments. Here, we describe the design and characterization of such nozzles assembled from ceramic micro-injection molded outer gas-focusing capillaries. Trends of the emitted jet diameter and jet length as a function of supplied liquid and gas flow rates are measured by a fast imaging system. The observed trends are explained by derived relationships considering choked gas flow and liquid flow conservation. Finally, the performance of these nozzles in a SFX experiment is presented, including an analysis of the observed background.

  7. Ceramic micro-injection molded nozzles for serial femtosecond crystallography sample delivery.

    Science.gov (United States)

    Beyerlein, K R; Adriano, L; Heymann, M; Kirian, R; Knoška, J; Wilde, F; Chapman, H N; Bajt, S

    2015-12-01

    Serial femtosecond crystallography (SFX) using X-ray Free-Electron Lasers (XFELs) allows for room temperature protein structure determination without evidence of conventional radiation damage. In this method, a liquid suspension of protein microcrystals can be delivered to the X-ray beam in vacuum as a micro-jet, which replenishes the crystals at a rate that exceeds the current XFEL pulse repetition rate. Gas dynamic virtual nozzles produce the required micrometer-sized streams by the focusing action of a coaxial sheath gas and have been shown to be effective for SFX experiments. Here, we describe the design and characterization of such nozzles assembled from ceramic micro-injection molded outer gas-focusing capillaries. Trends of the emitted jet diameter and jet length as a function of supplied liquid and gas flow rates are measured by a fast imaging system. The observed trends are explained by derived relationships considering choked gas flow and liquid flow conservation. Finally, the performance of these nozzles in a SFX experiment is presented, including an analysis of the observed background. PMID:26724070

  8. Model and simulation for melt flow in micro-injection molding based on the PTT model

    International Nuclear Information System (INIS)

    Unsteady viscoelastic flows were studied using the finite element method in this work. The Phan-Thien–Tanner (PTT) model was used to represent the rheological behavior of viscoelastic fluids. To effectively describe the microscale effects, the slip boundary condition and surface tension were added to the mathematical model for melt flow in micro-injection molding. The new variational equation of pressure, including the viscoelastic parameters and slip boundary condition, was generalized using integration by parts. A computer code based on the finite element method and finite difference method was developed to solve the melt flow problem. Numerical simulation revealed that the melt viscoelasticity plays an important role in the prediction of melt pressure, temperature at the gate and the succeeding melt front advancement in the cavity. Using the viscoelastic model one can also control the rapid increase in simulated pressure, temperature, and reduce the filling difference among different cavities. The short shot experiments of micro-motor shaft showed that the predicted melt front from the viscoelastic model is in fair agreement with the corresponding experimental results

  9. Foam injection molding of polypropylene/stainless steel fiber composites for efficient EMI shielding

    Science.gov (United States)

    Ameli, A.; Nofar, M.; Saniei, M.; Wang, S.; Park, C. B.

    2016-03-01

    Lightweight polypropylene/stainless-steel fiber (PP-SSF) composites with 15-35% density reduction were fabricated using foam injection molding and supercritical carbon dioxide (CO2). The electrical percolation threshold, through-plane electrical conductivity, and electromagnetic interference (EMI) shielding effectiveness (SE) of the PP-SSF composite foams were characterized and compared against the solid samples. The effects of the plasticizing gas and the void fraction on fiber breakage and orientation were also investigated. Microstructure characterization showed that the presence of dissolved CO2 decreased fiber breakage by about 30%, and together with foaming action, contributed to less preferential orientation of fibers. Consequently, the percolation threshold decreased up to four folds from 0.85 to 0.21 vol.% as the void fraction increased from 0 to 35%. The specific EMI SE was also significantly enhanced. A maximum specific EMI SE of 75 dB.g-1cm3 was achieved in PP-1.1 vol.% SSF composite foams, which was highly superior to 38 dB.g-1cm3 of the solid PP-1.0 vol.% SSF composites. The results reveal that light and efficient products with a lower fiber content can be developed by foam for EMI shielding applications.

  10. Rubber molds for investment casting

    International Nuclear Information System (INIS)

    The main objective of the project is to investigate different types of molding rubbers used for investment casting. The level of shape complexity which can be achieved by using these rubber molds is also studied. It was almost impossible to make complex shapes molds using metal molds, in that cases rubber molds are very important because they arc flexible and give accurate and precise part dimensions. Turbine blades are hi-tech components with air-foil geometries that have close dimensional tolerances. They are made of super-alloys and manufactured by investment casting. The final blade profile depends upon the dimensional accuracy in each of the processing steps. In the present work experimental study for the production of high quality low cost castings of turbine blades using rubber molds and injected wax patterns is presented. Natural Rubber molds and wax patterns from these molds were made. Different types of molding rubbers were studied including natural rubber, silicone rubber and liquid silicone rubber. It was found that by using rubber molds we can make most complex shape with very less finishing required. The shrinkage was 12% as compared to original master pattern. Rubber molds were made using laboratory hot press. Three layers of rubber above and below the master pattern. After that vulcanization was done by giving temperature and pressure. (author)

  11. Optimizing the fabrication process of a high-efficiency blazed grating through diamond scribing and molding

    International Nuclear Information System (INIS)

    This paper presents the experimental investigation of an optimal hot embossing process to prevent the nanoscale thermal deformation of microstructures replicated from the electroless Ni mold fabricated by the diamond tool-interfered scribing method. A polymer-based PMMA was replicated from the mold with the blazed profile: period 2.0 µm and depth 0.2 µm. The molding conditions, the applying pressure (Pm), molding temperature (Tm) and demolding temperature (Td) were chosen as experiment parameters. In terms of the quality of surface smoothness, profile, sharp edge, surface roughness and optical performance of the replica, the conditions, Pm = 0.9 MPa, Tm = 150 °C and Td = 20 °C, showed a best results. From optical testing, diffraction efficiency of the replica was measured, 87.6%, and the replica molded in other conditions showed a noticeable efficiency drop due to the molding error.

  12. Constante de mola de molas cerâmicas injetadas a baixa pressão Spring constant of low-pressure injection molded ceramic springs

    Directory of Open Access Journals (Sweden)

    R. A. Barbieri

    2011-12-01

    Full Text Available A dificuldade de usinagem de peças cerâmicas já sinterizadas é muito grande, principalmente devido à dureza e fragilidade destes materiais, o que implica em altos custos de produção. Por isso, grandes esforços tem sido feitos no sentido de melhorar os processos de conformação a verde existentes, ou criar novos processos que permitam a obtenção de peças cada vez mais próximas do formato final desejado. Produzir peças cerâmicas com formatos complexos, livres de defeitos, é uma tarefa que implica em grandes dificuldades. Molas cerâmicas possuem formatos extremamente difíceis de serem moldados e, conseqüentemente, atualmente são produzidas comercialmente molas cerâmicas pelo processo de usinagem, geralmente a um custo elevado. Uma alternativa para a produção de molas cerâmicas é a moldagem por injeção em baixa pressão. Para o desenvolvimento de molas cerâmicas para aplicações tecnológicas, é necessário, além de obter peças íntegras e livres de defeitos, aferir algumas de suas propriedades, como a constante de mola. Uma vez que estas molas encontram aplicação em altas temperaturas, torna-se imprescindível realizar a medida da resistência imposta pela mola à deformação elástica em diferentes temperaturas. Para tanto, este trabalho propõem a montagem de um sistema para a medição da constante de mola de molas cerâmicas injetadas a baixa pressão, tanto à temperatura ambiente como em altas temperaturas, usando o método dinâmico da excitação por impulso para medir a frequência de vibração da mola suspensa no interior de um forno. Para ilustrar a aplicação desta técnica são apresentados resultados obtidos para uma mola helicoidal de alumina, da temperatura ambiente até 1100 ºC.The machining of sintered ceramic parts is a difficult process, mainly due to the hardness and brittleness of these materials, which implies in high production costs. Therefore, great efforts have been made to improve the forming processes of green ceramics, or create new processes to obtain the near net shape parts. The production of ceramic parts with complex shapes, free of defects, is a task that involves great difficulties. Ceramic springs exhibits shapes extremely difficult to be molded and therefore are currently commercially produced mainly by machining, a process which is difficult and expensive. An alternative for the production of ceramic springs is by low-pressure injection molding. For the development of ceramic springs for technological applications, it is required in addition to getting parts intact and free of defects, to measure some of its properties, including the spring constant. Since these springs are usually applied at high temperatures, it becomes important to carry out the measurement of resistance imposed by the spring to elastic deformation at different temperatures. Accordingly, in this work we describe the assembly of an experiment for the measurement of the spring constant of low-pressure injection molded ceramic springs, both at ambient temperature and at high temperatures, using the dynamic impulse excitation method to measure the frequency of vibration of a suspended spring inside a furnace. Results are presented for a helical spring of alumina from room temperature to1100 ºC to illustrate the application of this technique.

  13. Constante de mola de molas cerâmicas injetadas a baixa pressão / Spring constant of low-pressure injection molded ceramic springs

    Scientific Electronic Library Online (English)

    R. A., Barbieri; J. E., Zorzi.

    2011-12-01

    Full Text Available A dificuldade de usinagem de peças cerâmicas já sinterizadas é muito grande, principalmente devido à dureza e fragilidade destes materiais, o que implica em altos custos de produção. Por isso, grandes esforços tem sido feitos no sentido de melhorar os processos de conformação a verde existentes, ou [...] criar novos processos que permitam a obtenção de peças cada vez mais próximas do formato final desejado. Produzir peças cerâmicas com formatos complexos, livres de defeitos, é uma tarefa que implica em grandes dificuldades. Molas cerâmicas possuem formatos extremamente difíceis de serem moldados e, conseqüentemente, atualmente são produzidas comercialmente molas cerâmicas pelo processo de usinagem, geralmente a um custo elevado. Uma alternativa para a produção de molas cerâmicas é a moldagem por injeção em baixa pressão. Para o desenvolvimento de molas cerâmicas para aplicações tecnológicas, é necessário, além de obter peças íntegras e livres de defeitos, aferir algumas de suas propriedades, como a constante de mola. Uma vez que estas molas encontram aplicação em altas temperaturas, torna-se imprescindível realizar a medida da resistência imposta pela mola à deformação elástica em diferentes temperaturas. Para tanto, este trabalho propõem a montagem de um sistema para a medição da constante de mola de molas cerâmicas injetadas a baixa pressão, tanto à temperatura ambiente como em altas temperaturas, usando o método dinâmico da excitação por impulso para medir a frequência de vibração da mola suspensa no interior de um forno. Para ilustrar a aplicação desta técnica são apresentados resultados obtidos para uma mola helicoidal de alumina, da temperatura ambiente até 1100 ºC. Abstract in english The machining of sintered ceramic parts is a difficult process, mainly due to the hardness and brittleness of these materials, which implies in high production costs. Therefore, great efforts have been made to improve the forming processes of green ceramics, or create new processes to obtain the nea [...] r net shape parts. The production of ceramic parts with complex shapes, free of defects, is a task that involves great difficulties. Ceramic springs exhibits shapes extremely difficult to be molded and therefore are currently commercially produced mainly by machining, a process which is difficult and expensive. An alternative for the production of ceramic springs is by low-pressure injection molding. For the development of ceramic springs for technological applications, it is required in addition to getting parts intact and free of defects, to measure some of its properties, including the spring constant. Since these springs are usually applied at high temperatures, it becomes important to carry out the measurement of resistance imposed by the spring to elastic deformation at different temperatures. Accordingly, in this work we describe the assembly of an experiment for the measurement of the spring constant of low-pressure injection molded ceramic springs, both at ambient temperature and at high temperatures, using the dynamic impulse excitation method to measure the frequency of vibration of a suspended spring inside a furnace. Results are presented for a helical spring of alumina from room temperature to1100 ºC to illustrate the application of this technique.

  14. Development of a compression molding process for three-dimensional tailored free-form glass optics.

    Science.gov (United States)

    Yi, Allen Y; Huang, Chunning; Klocke, Fritz; Brecher, Christian; Pongs, Guido; Winterschladen, Markus; Demmer, Axel; Lange, Sven; Bergs, Thomas; Merz, Michael; Niehaus, Frank

    2006-09-01

    Because of the limitation of manufacturing capability, free-form glass optics cannot be produced in a large volume using traditional processes such as grinding, lapping, and polishing. Very recently compression molding of glass optics became a viable manufacturing process for the high-volume production of precision glass optical components. An ultraprecision diamond-turning machine retrofitted with a fast tool servo was used to fabricate a free-form optical mold on a nickel-plated surface. A nonuniform rational B-spline trajectory generator was developed to calculate the computer numerical control machine tool path. A specially formulated glass with low transition temperature (Tg) was used, since the nickel alloy mold cannot withstand the high temperatures required for regular optical glasses. We describe the details of this process, from optical surface geometry, mold making, molding experiment, to lens measurement. PMID:16912790

  15. RESEARCH ON THE CONTENT AND FILLER TYPE ON INJECTION SHRINKAGE

    OpenAIRE

    Tomasz Jachowicz; Ivan Gajdoš; Volodymyr Krasinskyi

    2014-01-01

    The paper presents the phenomenon of injection shrinkage. The definition of shrinkage and shrinkage types are presented. The main factors affecting shrinkage value of injection-molded part are discussed. Based on the experimental tests conducted using injection-molded parts made from polypropylene filled with glass fiber and talc, the dependence of injection-molded part shrinkage on filler content and selected parameters of the injection molding process has been determined.

  16. RESEARCH ON THE CONTENT AND FILLER TYPE ON INJECTION SHRINKAGE

    Directory of Open Access Journals (Sweden)

    Tomasz Jachowicz

    2014-09-01

    Full Text Available The paper presents the phenomenon of injection shrinkage. The definition of shrinkage and shrinkage types are presented. The main factors affecting shrinkage value of injection-molded part are discussed. Based on the experimental tests conducted using injection-molded parts made from polypropylene filled with glass fiber and talc, the dependence of injection-molded part shrinkage on filler content and selected parameters of the injection molding process has been determined.

  17. Thermal and mechanical properties of injection molded recycled high density polyethylene blends with virgin isotactic polypropylene

    International Nuclear Information System (INIS)

    Highlights: ► Recycled high density polyethylene and isotactic polypropylene blends have been prepared by melt compounding. ► Thermal study showed that iPP is not well dispersed into the rHDPE matrix. ► Tensile testing shows that there is strong correlation between the thermal properties and the tensile behavior of rHDPE/ipp blends. - Abstract: Polymer blending has become an important field in polymer research and especially in the area of recycling. In this research the target was to reduce the polymer waste problem. Therefore, recycled high density polyethylene (rHDPE) and virgin isotactic polypropylene (vPP) blends containing upto 30 wt% of vPP have been prepared by melt compounding method using injection molding at 220 °C. The thermal properties, thermal degradation and the mechanical properties of the polymer blends were studied using differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA), and tensile testing method. DSC study shows that in all the blends there are two melting peaks, one around the melting temperature of rHDPE and another one around the melting point of vPP, indicating that vPP is not well dispersed into the rHDPE matrix. The changes in the heat of fusion for the rHDPE/iPP polymer blends versus vPP content suggests that incorporating vPP affects the crystallinity of the system. TGA analysis of the polymer blends shows that parts of rHDPE with 95/5 upto 80/20 of vPP are mostly stable composition which brings about valuable stabilization to the rHDPE. Tensile testing shows that there is strong correlation between the thermal properties and the tensile behavior of rHDPE/vpp blends

  18. Permeability Tests of Fiber Fabrics in the Vacuum Assisted Resin Transfer Molding Process

    Science.gov (United States)

    Changchun, Wang; Guanghui, Bai; Yang, Wang; Boming, Zhang; Lijian, Pan

    2015-08-01

    A special device is designed to measure the in-plane and through-thickness permeability of a preform for the vacuum assisted resin transfer molding (VARTM) process. The device is composed of pressure control module, aluminum experimental platform, thickness test module, and pressure test module, which is controlled by a computer. Two kinds of experiments were conducted for carbon fiber noncrimp biaxial fabrics to verify the reliability of the new device based on constant pressure injection. The two experiments are composed of: (1) testing of in-plane permeability for 1, 5, 10 and 20 layers with the method of the line injection by comparing the two conventional methods; (2) testing of the through-thickness permeability for the laminate denoted as [±45] 20 with the central injection method. The results show: (1) the in-plane permeability decrease with the increase of layer number and the permeability for 20 layers is only 62 % of the one layer; (2) the in-plane permeability is an order of magnitude greater than through-thickness permeability based on experimental results of laminate denoted as [±45] 20. A good agreement obtained between the device and two comparison methods proves the validity of the device.

  19. Die-sinking electrical discharge machining of a high-strength copper-based alloy for injection molds

    Scientific Electronic Library Online (English)

    F. L., Amorim; W. L., Weingaertner.

    2004-06-01

    Full Text Available High-strength copper alloys are used as materials for injection molding tools or as cores and inserts in steel molds because of their high thermal conductivity, corrosion and wear resistance. Unfortunately, there is little technological knowledge on the electrical discharge machining (EDM) of copper [...] -beryllium ASTM C17200 alloy. In this work, rough and finish machining conditions were tested using copper and tungsten-copper as materials for the electrodes. Cross-sectional micrographic and hardness examinations as well as surface roughness measurements were also carried out on workpieces after machining in order to study the thermally affected zones. Appropriate parameters settings for EDM of the investigated alloy are suggested.

  20. Flow injection systems for process analytical chemistry

    OpenAIRE

    Lukkari, Ingrid

    1995-01-01

    Flow injection systems have great potential for sample handling and analysis in process analytical chemistry. The flexibility and versatility of flow injection manifolds can he utilized in specific applications of sample conditioning and analysis. An overview of various flow injection methods, including flow reversals, double injection, and sequential injection is given, as well as different clean-up methods, such as gas diffusion, solid phase extraction, dialysis, and solvent extraction. Cal...

  1. Analysis of Optimal Injection Moulding Process Parameters for Thin-Shell Plastic Product Using Response Surface Methodology

    OpenAIRE

    Awang Bono; Jumat Sulaiman; S. Rajalingam

    2014-01-01

    The injection molding process is used to produce thin-walled plastic products for a wide variety of applications. However, the difficulty in adjusting optimum process parameters setting may cause defects on injected moulded parts such as shrinkage. A study was conducted for the determination of the optimal injection moulding process parameters which will minimize the shrinkage defect on a thin-shell plastic product for cell phone housing component. The machine process setting in use currently...

  2. Moldagem por injeção de pós cerâmicos: remoção da parafina e do polipropileno utilizados como veículo orgânico / Ceramic injection molding: removal of pafafin and polypropylene used as organic binder

    Scientific Electronic Library Online (English)

    Ricardo V. B., Oliveira; Eduardo A., Pinheiro; Valdir, Soldi; Alfredo T. N., Pires; Márcio C., Fredel.

    2004-09-01

    Full Text Available A moldagem por injeção de pós cerâmicos tem se tornado um processo altamente atrativo por aliar a versatilidade e a produtividade da moldagem por injeção convencional às propriedades inerentes aos materiais cerâmicos. A remoção do ligante, usado como veículo orgânico nesse processo, é uma das etapas [...] críticas para a produção de peças cerâmicas sem defeitos. Neste trabalho avaliou-se a influência da geometria das peças injetadas na remoção do ligante, tanto por imersão em solvente como por decomposição térmica. Alumina em pó foi misturada fisicamente a um ligante composto por polipropileno [PP], parafina [PW] e ácido esteárico [AE]. As peças com diferentes geometrias foram mantidas imersas em hexano, secas sob vácuo e acompanhada a variação de massa devido à solubilização do PW e AE. A determinação da porosidade das peças, realizada por meio das isotermas de adsorção/desorção de nitrogênio, mostrou um aumento de porosidade de 0,5% volume para aproximadamente 20% volume após a imersão em solvente. A remoção térmica do PP remanescente produziu hidrocarbonetos alifáticos e compostos insaturados, determinados e quantificados por espectroscopia de infravermelho, que permearam a estrutura porosa da peça. A geometria das peças tem grande influência na remoção do ligante, podendo afetar não só a qualidade do produto final, mas também as etapas subseqüentes do processo. Abstract in english Powder injection molding [PIM] has become highly attractive as it combines the versatility and productivity of conventional injection molding processes with the intrinsic properties of metallic and ceramic materials. The removal of organic binder, used as vehicles during the process, is one of the m [...] ost critical stages in the production of ceramic devices in this process. In this work, the influence from the geometry of the injected part on the removal of the organic binder was evaluated for both solvent immersion and thermal degradation processes. Alumina powder was mixed with an organic binder, comprising polypropylene [PP], paraffin wax [PW] and stearic acid [SA], and injection molded in different geometries. Immersion of ceramic parts in hexane induced the solubilization of PW and SA, confirmed by weight variation. Parts porosity, determined through nitrogen adsorption isotherm, showed an increase from 0.5 v% before immersion to ca. 20 v% after immersion. PP burnout produced aliphatic hydrocarbons and unsaturated compounds that flow through a porous structure produced in early stages of this process. Parts geometry plays an important role in binder removal, affecting the quality of the sintered part as well as the remaining stages of the process.

  3. Moldagem por injeção de pós cerâmicos: remoção da parafina e do polipropileno utilizados como veículo orgânico Ceramic injection molding: removal of pafafin and polypropylene used as organic binder

    Directory of Open Access Journals (Sweden)

    Ricardo V. B. Oliveira

    2004-09-01

    Full Text Available A moldagem por injeção de pós cerâmicos tem se tornado um processo altamente atrativo por aliar a versatilidade e a produtividade da moldagem por injeção convencional às propriedades inerentes aos materiais cerâmicos. A remoção do ligante, usado como veículo orgânico nesse processo, é uma das etapas críticas para a produção de peças cerâmicas sem defeitos. Neste trabalho avaliou-se a influência da geometria das peças injetadas na remoção do ligante, tanto por imersão em solvente como por decomposição térmica. Alumina em pó foi misturada fisicamente a um ligante composto por polipropileno [PP], parafina [PW] e ácido esteárico [AE]. As peças com diferentes geometrias foram mantidas imersas em hexano, secas sob vácuo e acompanhada a variação de massa devido à solubilização do PW e AE. A determinação da porosidade das peças, realizada por meio das isotermas de adsorção/desorção de nitrogênio, mostrou um aumento de porosidade de 0,5% volume para aproximadamente 20% volume após a imersão em solvente. A remoção térmica do PP remanescente produziu hidrocarbonetos alifáticos e compostos insaturados, determinados e quantificados por espectroscopia de infravermelho, que permearam a estrutura porosa da peça. A geometria das peças tem grande influência na remoção do ligante, podendo afetar não só a qualidade do produto final, mas também as etapas subseqüentes do processo.Powder injection molding [PIM] has become highly attractive as it combines the versatility and productivity of conventional injection molding processes with the intrinsic properties of metallic and ceramic materials. The removal of organic binder, used as vehicles during the process, is one of the most critical stages in the production of ceramic devices in this process. In this work, the influence from the geometry of the injected part on the removal of the organic binder was evaluated for both solvent immersion and thermal degradation processes. Alumina powder was mixed with an organic binder, comprising polypropylene [PP], paraffin wax [PW] and stearic acid [SA], and injection molded in different geometries. Immersion of ceramic parts in hexane induced the solubilization of PW and SA, confirmed by weight variation. Parts porosity, determined through nitrogen adsorption isotherm, showed an increase from 0.5 v% before immersion to ca. 20 v% after immersion. PP burnout produced aliphatic hydrocarbons and unsaturated compounds that flow through a porous structure produced in early stages of this process. Parts geometry plays an important role in binder removal, affecting the quality of the sintered part as well as the remaining stages of the process.

  4. Tool steel quality and surface finishing of plastic molds

    Directory of Open Access Journals (Sweden)

    Rafael Agnelli Mesquita

    2010-01-01

    Full Text Available Plastic industry is today in a constant growth, demanding several products from other segments, which includes the plastic molds, mainly used in the injection molding process. Considering all the requirements of plastic molds, the surface finishing is of special interest, as the injected plastic part is able to reproduce any details (and also defects from the mold surface. Therefore, several aspects on mold finishing are important, mainly related to manufacturing conditions - machining, grinding, polishing and texturing, and also related to the tool steel quality, in relation to microstructure homogeneity and non-metallic inclusions (cleanliness. The present paper is then focused on this interrelationship between steel quality and manufacturing process, which are both related to the final quality of plastic mold surfaces. Examples are discussed in terms of surface finishing of plastic molds and the properties or the microstructure of mold steels.

  5. Fabrication of combined-scale nano- and microfluidic polymer systems using a multilevel dry etching, electroplating and molding process

    DEFF Research Database (Denmark)

    Tanzi, Simone; Østergaard, Peter Friis; Matteucci, Marco; Christiansen, Thomas Lehrmann; Cech, Jiri; Marie, Rodolphe; Taboryski, Rafael J.

    2012-01-01

    Microfabricated single-cell capture and DNA stretching devices have been produced by injection molding. The fabrication scheme employed deep reactive ion etching in a silicon substrate, electroplating in nickel and molding in cyclic olefin polymer. This work proposes technical solutions to fabrication challenges associated with chip sealing and demolding of polymer high-volume replication methods. UV-assisted thermal bonding was found to ensure a strong seal of the microstructures in the molded ...

  6. Application of Artificial Vision in flow redirection during filling of Liquid Composite Molding processes

    Science.gov (United States)

    Montés, N.; Sanchez, F.; García, J. A.; Falcó, A.; Tornero, J.; Chinesta, F.

    2007-04-01

    The control techniques applied in Liquid Composite Molding processes have been extensively worked out by many different research groups abroad. In this work, the original use of artificial vision technology in order to redirect the flow path during mold filling appears as a major objective of online control strategy. In this study, a process performance index developed in a previous work is used to define the mold gate opening sequence. The Vacuum Assisted Resin Transfer Molding (VARTM) and Vacuum Assisted Resin Infusion (VARI) have been selected as the main processes of study. The expert system will make use of numerical simulation in order to obtain a previous physical understanding of the flow behaviour in different manufacturing conditions. Some examples of the installation are presented and discussed.

  7. Moldes de ABS construídos pelo processo de modelagem por fusão e deposição para injeção de PP e PEBD / PP and LDPE injection in ABS molds built with fused deposition modeling

    Scientific Electronic Library Online (English)

    José A., Foggiatto; Carlos H., Ahrens; Gean V., Salmoria; Alfredo T. N., Pires.

    2004-12-01

    Full Text Available Os processos de prototipagem rápida (Rapid Prototyping - RP) e ferramental rápido (Rapid Tooling - RT) surgiram para reduzir os tempos de desenvolvimento de produtos na fase de projeto diminuindo a necessidade de retrabalhos e, conseqüentemente, antecipando a entrada de novos produtos no mercado. Ne [...] ste trabalho foi utilizada uma das tecnologias de prototipagem rápida, denominada Modelagem por Fusão e Deposição (FDM), na construção de moldes em ABS com o objetivo de investigar sua aplicação na moldagem por injeção de termoplásticos. Amostras das peças injetadas foram submetidas a ensaios de difração de raios X, dureza Shore D e tração. Os resultados mostraram a viabilidade de fabricar pequenos lotes de peças em PEBD e PP com propriedades mecânicas bastante similares às encontradas em peças moldadas em moldes metálicos. Abstract in english Rapid Prototyping and Rapid Tooling are aimed at reducing the development time of products in the design phase by minimizing re-workings and, consequently, reducing the time to launch new products. In this work one of the technologies of rapid prototyping, called Fused Deposition Modeling (FDM), was [...] used in the construction of ABS molds with the objective of investigating its application in the injection molding of thermoplastics. Specimens of the molded parts were characterized with X-ray diffraction, Shore D hardness and tensile tests. The results demonstrated the viability to manufacture small batches of LDPE and PP parts with mechanical properties similar to those molded parts in metallic molds.

  8. Moldes de ABS construídos pelo processo de modelagem por fusão e deposição para injeção de PP e PEBD PP and LDPE injection in ABS molds built with fused deposition modeling

    Directory of Open Access Journals (Sweden)

    José A. Foggiatto

    2004-12-01

    Full Text Available Os processos de prototipagem rápida (Rapid Prototyping - RP e ferramental rápido (Rapid Tooling - RT surgiram para reduzir os tempos de desenvolvimento de produtos na fase de projeto diminuindo a necessidade de retrabalhos e, conseqüentemente, antecipando a entrada de novos produtos no mercado. Neste trabalho foi utilizada uma das tecnologias de prototipagem rápida, denominada Modelagem por Fusão e Deposição (FDM, na construção de moldes em ABS com o objetivo de investigar sua aplicação na moldagem por injeção de termoplásticos. Amostras das peças injetadas foram submetidas a ensaios de difração de raios X, dureza Shore D e tração. Os resultados mostraram a viabilidade de fabricar pequenos lotes de peças em PEBD e PP com propriedades mecânicas bastante similares às encontradas em peças moldadas em moldes metálicos.Rapid Prototyping and Rapid Tooling are aimed at reducing the development time of products in the design phase by minimizing re-workings and, consequently, reducing the time to launch new products. In this work one of the technologies of rapid prototyping, called Fused Deposition Modeling (FDM, was used in the construction of ABS molds with the objective of investigating its application in the injection molding of thermoplastics. Specimens of the molded parts were characterized with X-ray diffraction, Shore D hardness and tensile tests. The results demonstrated the viability to manufacture small batches of LDPE and PP parts with mechanical properties similar to those molded parts in metallic molds.

  9. Predictive engineering tools for injection-molded long-carbon-fiber thermoplastic composites - FY 2015 third quarterly report

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mori, Steven [MAGNA Exteriors and Interiors Corp. Aurora, ON (Canada); Gandhi, Umesh N. [Toyota Research Institute North America, Ann Arbor, MI (United States); Wang, Jin [Autodesk, Inc., Ithaca, NY (United States); Costa, Franco [Autodesk, Inc., Ithaca, NY (United States); Wollan, Eric J. [PlastiComp, Inc., Winona, MN (United States); Tucker, III, Charles L. [Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)

    2015-07-01

    During the third quarter of FY 2015, the following technical progress has been made toward project milestones: 1) Magna oversaw the tool build and prepared the molding plan for the complex part of Phase II. 2) PlastiComp hosted a visit by Magna and Toyota on April 23rd to finalize the molding scope and schedule. The plan for molding trials including selection of molding parameters for both LFT and D-LFT for the U-shape complex part was established. 3) Toyota shipped the U-shape complex part tool to Magna on May 28th, 2015. 4) Plasticomp provided 30wt% LCF/PP and 30wt% LCF/PA66 compounded pellets to Magna for molding the complex part. 5) Magna performed preliminary molding trials on June 2nd, 2015 to validate wall thickness, fill profile, tool temperature and shot size requirements for the complex part. 6) Magna performed the first complex part run on June 16th and 17th, 2015 at Magna’s Composite Centre of Excellence in Concord, ON, Canada. Dale Roland of Plasticomp, and Umesh Gandhi of Toyota also attended the molding. 7) Magna discussed and finalized the plan with PNNL and the team for cutting samples from molded parts at selected locations for fiber orientation and length measurements. 8) Magna provided the computer-aided design (CAD) files of the complex parts with and without ribs to PNNL and Autodesk to build the corresponding ASMI models for injection molding simulations. Magna also provided the actual parameters used. 9) Plasticomp’s provided knowledge and experience of molding LCF materials essential to the successful molding of the parts including optimization of fill speed, tool temperatures, and plasticizing conditions for the 30wt% LCF/PP and 30wt% LCF/PA66 materials in both rib and non-rib versions. 10) Magna molded additional parts for evaluation of mechanical property testing including torsional stiffness on June 29th and 30th, 2015 at Magna’s Composite Center of Excellence. 11) Toyota began preparation for the torsion test of the specimens. Preparation of a computer-aided engineering (CAE) model to predict the performance is in progress. 12) Autodesk fixed an error in the implementation of the proper orthogonal decomposition (POD) calculation of fiber length that had caused the ASMI solution to crash and provided an updated build of ASMI containing the fix. 13)Autodesk reviewed and provided feedback for the complex part molding and measurement locations. 14) Autodesk provided support to set up the workflow for ASMI-ABAQUS® analysis, and provided a fix and workaround for a bug in the ASMI-ABAQUS® output command. 15) Autodesk helped build ASMI analysis models for the complex parts with and without ribs. 16) Autodesk worked on improving the orientation prediction accuracy in the shearing layer for 3D meshes based on comparison to measured data of the plaque moldings. 17) PNNL installed a new ASMI version received from Autodesk and performed comparative analyses to assess mid-plane versus 3D fiber length predictions using the full fiber length model and the reduced-order model (ROM) using POD. 18) PNNL presented the project scope, accomplishments, significant results and future plans to DOE and the USCAR Materials Tech Team on June 3rd, 2015. 19) PNNL discussed the cutting of samples from molded parts and finalized a plan with Magna and the team suggesting the sample size, locations and number of samples per location. 20) PNNL and Autodesk built ASMI models for the complex parts with and without ribs, and preliminary analyses of the part with ribs were conducted using the actual molding parameters received from Magna. 21) PNNL worked on a procedure to extract fiber orientation and length results from a 3D ASMI analysis to a 3D ABAQUS model. This procedure is essential to import ASMI fiber orientation and length to a 3D ABAQUS model of the part allowing future part structural analysis for weight reduction study.

  10. Effect of mold rotation on inclusion distribution in bearing steel during electroslag remelting process

    OpenAIRE

    Chang Lizhong; Shi Xiaofang; Wang Runxi

    2014-01-01

    To remove the inclusions in the ingots by conventional electroslag remelting (ESR), the bearing steel was prepared using ESR process but with mold rotation in this study. Experimental results show a reduction in amount of large inclusions when the mold rotation rate is 6 r·min-1, and the inclusions are uniformly distributed in the ESR ingot. As comparison with the electroslag ingots of conventional ESR (stationary mold), the portion of the Al2O3 inclusions smaller than 1 ?m in size increase f...

  11. Spray forming process for producing molds, dies and related tooling

    Science.gov (United States)

    McHugh, Kevin M. (Idaho Falls, ID); Key, James F. (Idaho Falls, ID)

    1998-01-01

    A method for spray forming manufacturing of near-net-shape molds, dies and related toolings, wherein liquid material such as molten metal, metallic alloys, or polymers are atomized into fine droplets by a high temperature, high velocity gas and deposited onto a pattern. Quenching of the atomized droplets provides a heat sink, thereby allowing undercooled and partially solidified droplets to be formed in-flight. Composites can be formed by combining the atomized droplets with solid particles such as whiskers or fibers.

  12. Desenvolvimento de liga sinterizada de níquel por moldagem de pós por injeção / Development of sintered nickel alloy by powder injection molding

    Scientific Electronic Library Online (English)

    Moisés Luiz, Parucker; Aloisio Nelmo, Klein; Roberto, Binder.

    2014-09-01

    Full Text Available A moldagem de pós por injeção é um processo de fabricação de elevada produtividade que possibilita obter componentes de geometria complexa, estreita precisão dimensional e boas propriedades mecânicas. Neste processo, uma mistura de uma determinada quantidade de pós e ligantes orgânicos (polímeros, c [...] eras e óleos) é obtida por meio de uma massa de injeção (feedstock) o qual tem características reológicas adequadas para promover a injeção desta massa em uma cavidade de um molde. A produção de ligas de níquel por meio deste processo é uma alternativa para produção de produtos que requerem aplicações avançadas onde se exige resistência a corrosão e oxidação, resistência mecânica a altas temperaturas e baixo coeficiente de atrito. Neste trabalho apresentamos um estudo das propriedades microestruturais e mecânicas de uma liga de níquel (Ni-Fe-Cr-P) processada via moldagem de pós por injeção, utilizando pós de níquel carbonila com e sem a presença de fase líquida durante a sinterização. Os resultados foram comparados com a mesma liga processada por compactação de pós. Os resultados demonstraram a necessidade de maior quantidade de matéria orgânica para o desenvolvimento da massa de injeção (feedstock: 15% m/m de polímero) para os tipos de pós metálicos utilizados (níquel carbonila do tipo INCO 123) se comparado ao feedstock de ligas comerciais que normalmente utilizam uma quantidade menor de matéria orgânica (feedstock: 9% m/m de polímero). A maior quantidade de matéria orgânica necessária para a preparação do feedstock deve-se a morfologia dos pós empregados (superficie rugosa - tipo spiky) que promove retenção de carbono durante o processo de extração, ocasionando a necessidade de otimização do ciclo de extração térmica e sinterização. Ciclos mais lentos e a baixa temperatura promoveram a total retirada dos ligantes. A liga de Ni-Fe-Cr-P injetada apresentou contração de aproximadamente 50%, além de elevado teor de poros quando comparado ao material compactado, o que influenciou as propriedades mecânicas e dureza aparente do material. Abstract in english The powder injection molding is a manufacturing process that allows high productivity to obtain complex geometry components, dimensional accuracy and good mechanical properties. In this process, a mixture of a quantity of powders and organic binders (polymers, waxes, oils) is obtained through inject [...] ion of a mass (feedstock) which has rheological properties suitable for promoting the injection of this mass in a cavity of a mold. The production of nickel alloy by this process is an alternative to production of products that require advanced applications, which require resistance to corrosion and oxidation, mechanical strength at high temperatures and low coefficient of friction. This paper we present the study of the microstructural and mechanical properties of a nickel alloy (Ni-Fe-Cr-P) processed by powder injection molding, using carbonyl nickel powders with and without the presence of liquid phase during sintering. The results are compared with the alloy processed by powder compaction. The results demonstrate the need for increased amount of organic matter for developing the injection mass (feedstock: 15 wt.% polymer) for the types of metallic powders used (nickel INCO type 123 carbonyl) compared to commercial alloy feedstock typically use a smaller amount of organic matter (feedstock: 9 wt.% polymer). The largest quantity of organic matter needed for the preparation of the feedstock due to the morphology of the powders used (spiky) which promoted carbon retention during the extraction process, resulting in the need to optimize the extraction cycle and thermal sintering. Slower cycles and low temperature promoted the complete extraction of the ligands. The Ni-Fe-Cr-P alloy injected showed shrinkage of approximately 50%, and high levels of pores as compared to the compacted material, which influenced the mechanical properties and apparent hardness of the material.

  13. Effect of Zr, Nb and Ti addition on injection molded 316L stainless steel for bio-applications: Mechanical, electrochemical and biocompatibility properties.

    Science.gov (United States)

    Gulsoy, H Ozkan; Pazarlioglu, Serdar; Gulsoy, Nagihan; Gundede, Busra; Mutlu, Ozal

    2015-11-01

    The research investigated the effect of Zr, Nb and Ti additions on mechanical, electrochemical properties and biocompatibility of injection molded 316L stainless steel. Addition of elemental powder is promoted to get high performance of sintered 316L stainless steels. The amount of additive powder plays a role in determining the sintered microstructure and all properties. In this study, 316L stainless steel powders used with the elemental Zr, Nb and Ti powders. A feedstock containing 62.5 wt% powders loading was molded at different injection molded temperature. The binders were completely removed from molded components by solvent and thermal debinding at different temperatures. The debinded samples were sintered at 1350°C for 60 min. Mechanical, electrochemical property and biocompatibility of the sintered samples were performed mechanical, electrochemical, SBF immersion tests and cell culture experiments. Results of study showed that sintered 316L and 316L with additives samples exhibited high corrosion properties and biocompatibility in a physiological environment. PMID:26275484

  14. Vacuum-assisted resin transfer molding (VARTM) model development, verification, and process analysis

    Science.gov (United States)

    Sayre, Jay Randall

    2000-12-01

    Vacuum-Assisted Resin Transfer Molding (VARTM) processes are becoming promising technologies in the manufacturing of primary composite structures in the aircraft industry as well as infrastructure. A great deal of work still needs to be done on efforts to reduce the costly trial-and-error methods of VARTM processing that are currently in practice today. A computer simulation model of the VARTM process would provide a cost-effective tool in the manufacturing of composites utilizing this technique. Therefore, the objective of this research was to modify an existing three-dimensional, Resin Film Infusion (RFI)/Resin Transfer Molding (RTM) model to include VARTM simulation capabilities and to verify this model with the fabrication of aircraft structural composites. An additional objective was to use the VARTM model as a process analysis tool, where this tool would enable the user to configure the best process for manufacturing quality composites. Experimental verification of the model was performed by processing several flat composite panels. The parameters verified included flow front patterns and infiltration times. The flow front patterns were determined to be qualitatively accurate, while the simulated infiltration times over predicted experimental times by 8 to 10%. Capillary and gravitational forces were incorporated into the existing RFI/RTM model in order to simulate VARTM processing physics more accurately. The theoretical capillary pressure showed the capability to reduce the simulated infiltration times by as great as 6%. The gravity, on the other hand, was found to be negligible for all cases. Finally, the VARTM model was used as a process analysis tool. This enabled the user to determine such important process constraints as the location and type of injection ports and the permeability and location of the high-permeable media. A process for a three-stiffener composite panel was proposed. This configuration evolved from the variation of the process constraints in the modeling of several different composite panels. The configuration was proposed by considering such factors as: infiltration time, the number of vacuum ports, and possible areas of void entrapment.

  15. Fabrication of combined-scale nano- and microfluidic polymer systems using a multilevel dry etching, electroplating and molding process

    DEFF Research Database (Denmark)

    Tanzi, Simone; Østergaard, Peter Friis

    2012-01-01

    Microfabricated single-cell capture and DNA stretching devices have been produced by injection molding. The fabrication scheme employed deep reactive ion etching in a silicon substrate, electroplating in nickel and molding in cyclic olefin polymer. This work proposes technical solutions to fabrication challenges associated with chip sealing and demolding of polymer high-volume replication methods. UV-assisted thermal bonding was found to ensure a strong seal of the microstructures in the molded part without altering the geometry of the channels. In the DNA stretching device, a low aspect ratio nanoslit (1/200) connecting two larger micro-channels was used to stretch a 168.5 kbp DNA molecule, while in the other device single-HeLa cells were captured against a micro-aperture connecting two larger microfluidic channels. Different dry etching processes have been investigated for the master origination of the cell-capture device. The combination of a modified Bosch process and an isotropic polysilicon etch was found to ensure the ease of demolding by resulting in slightly positively tapered sidewalls with negligible undercut at the mask interface.

  16. Fabrication of combined-scale nano- and microfluidic polymer systems using a multilevel dry etching, electroplating and molding process

    International Nuclear Information System (INIS)

    Microfabricated single-cell capture and DNA stretching devices have been produced by injection molding. The fabrication scheme employed deep reactive ion etching in a silicon substrate, electroplating in nickel and molding in cyclic olefin polymer. This work proposes technical solutions to fabrication challenges associated with chip sealing and demolding of polymer high-volume replication methods. UV-assisted thermal bonding was found to ensure a strong seal of the microstructures in the molded part without altering the geometry of the channels. In the DNA stretching device, a low aspect ratio nanoslit (1/200) connecting two larger micro-channels was used to stretch a 168.5 kbp DNA molecule, while in the other device single-HeLa cells were captured against a micro-aperture connecting two larger microfluidic channels. Different dry etching processes have been investigated for the master origination of the cell-capture device. The combination of a modified Bosch process and an isotropic polysilicon etch was found to ensure the ease of demolding by resulting in slightly positively tapered sidewalls with negligible undercut at the mask interface. (paper)

  17. Characteristics and infl uence factors of mold fi lling process in permanent mold with a slot gating system

    OpenAIRE

    Chen Changjun; Chen Xia; Chang Qingming

    2009-01-01

    The main problems caused by improper gating are entrained aluminum oxide fi lms and entrapped gas. In this study, the slot gating system is employed to improve mold fi lling behavior and therefore, to improve the quality of aluminum castings produced in permanent molds. An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum fl owing into permanent molds have been developed. Graphite molds transparent to X-rays are utilized which make it possible to obs...

  18. Unsaturated and Saturated Flow Front Tracking in Liquid Composite Molding Processes using Dielectric Sensors

    Science.gov (United States)

    Carlone, P.; Palazzo, G. S.

    2015-10-01

    Liquid composite molding processes are manufacturing techniques involving the impregnation and saturation of dry fibrous preforms by means of injection or infusion of catalyzed resin systems. Complete wetting of the reinforcement and reduction of voids are key issues to enhance mechanical properties of the final product, as a consequence on line monitoring and control of resin flow is highly desirable to detect and avoid potentialbet macro- as well as micro-voids. In this paper, parallel-plate dielectric sensors were investigated to track the position of unsaturated as well as saturated flow fronts through dual scale porous media. Sensors configuration was analyzed and improved via electromagnetic (EM) finite element simulations. The effectiveness of the proposed system was assessed in one-dimensional impregnation tests. Good agreement was found between unsaturated front positions provided by the considered system and acquired through conventional visual techniques. An indirect verification strategy, based on CFD and EM simulations of the process, was applied to investigate the reliability of dielectric sensors with respect to saturation phenomena. Obtained outcomes highlighted the intriguing capabilities of the proposed method.

  19. The Effect of Dewaxing and Burnout Temperature in Block Mold Process for Copper Alloy Casting

    Directory of Open Access Journals (Sweden)

    S.Z. Mohd Nor

    2015-10-01

    Full Text Available The main objective of this research is to investigate the effect of dewaxing and burnout temperature on the quality of copper alloy casting produced by a low cost block mold that has been developed. In the molding process, two types of silica sand which contains 97.9% silica (SiO2 and 97.2% silica have been used as a refractory material with POP served as a binder. Several mold formulations contained 15-40% plaster of paris (POP, 60-85% silica sand and 35% water had been developed and each formulation had been tested in the process of copper alloy casting. In the dewaxing process, the temperature of 170oC was found appropriate to be used as an initial mold heating temperature and complete wax burnout was effectively achieved with the temperature of 750oC for 5 hours. The insufficient burnout process has produced a defect casting with carbon residue, appeared as a black stain on the surface of the casting. Meanwhile, rapid initial heating had prevented the wax from flowing out smoothly thus, eroded the surface of the mold cavities. This has resulted in deteriorated cavity surface, hence a rough surface of the casting.

  20. Innovations in molding technologies for microfabrication

    Science.gov (United States)

    Benzler, Tobias; Piotter, Volker; Hanemann, Thomas; Mueller, K.; Norajitra, Prachai; Ruprecht, Robert; Hausselt, Juergen H.

    1999-08-01

    Micromolding is a key technology for the economic production of components for microsystems. It is applied in several manufacturing techniques including the LIGA process. Especially MicroInjection Molding allows cost-effective large-scale production of components for many applications to be used in microsystems technology. Using special molding machines, lateral dimensions in the micrometer range, structural details down to 200nm and maximum aspect ratios of more than 20 are achieved. Examples for applications are PSU-made housings for microfluidic systems or microcomponents made of PMMA for cardiac catheters. PC or LCP are appropriate materials for interconnection devices in microoptics and electronics. Other examples are injection molded lost plastic molds for electroforming or electroless plating of metal microstructures. An important economic factor is the optimization of the molding process and tool using different simulation techniques. Recently, novel techniques for manufacturing metal or ceramic microstructures were developed by adapting Powder Injection Molding to microtechnologies. Using commercially available feedstocks, microstructures were made of metals or ceramics. Rapid manufacturing of microcomponents is achieved by the so-called Photomolding process using reactive polymer resins as photocurable material and e.g. mold inserts fabricated by laser ablation. The addition of micro- or nanosized ceramics to the resin allows the molding of filled composite with enhanced mechanical properties. Subsequent debindering and sintering steps yield the pure ceramic microcomponents.

  1. Mold Simulator Study of the Initial Solidification of Molten Steel in Continuous Casting Mold. Part I: Experiment Process and Measurement

    Science.gov (United States)

    Zhang, Haihui; Wang, Wanlin; Ma, Fanjun; Zhou, Lejn

    2015-10-01

    A mold simulator has been successfully used to study the initial solidification behavior of the molten low carbon steel. Coupled with 2D-IHCD calculation and PSD analysis, the variations of the responding temperatures and heat fluxes, as well as the relationship between shell surface profile, heat flux, shell thickness, mold level fluctuation, and the infiltrated slag film, were investigated in this article. The results suggested that the mold high-frequency temperatures and heat fluxes above liquid steel level vary with the oscillation of the mold, and show an opposite variation pattern as those below the shell tip. The formed shell surface profile is directly correlated to the variation of high-frequency heat fluxes, where the formation of oscillation mark is associated with a sudden increase of the heat flux during negative strip time. Mold level fluctuation contributes to the formation of the extra oscillation marks. The growth of shell thickness follows the square root law, and the instantaneous solidification factor is large near the shell tip and becomes small in the area where the deep shell surface depression is formed. The thickness of the slag film in between mold and shell is in the range of 1.4 to 2.46 mm, and the crystallization of mold flux in mold/shell gap is dynamic.

  2. In-Situ Real Time Monitoring and Control of Mold Making and Filling Processes: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed Abdelrahman; Kenneth Currie

    2010-12-22

    This project presents a model for addressing several objectives envisioned by the metal casting industries through the integration of research and educational components. It provides an innovative approach to introduce technologies for real time characterization of sand molds, lost foam patterns and monitoring of the mold filling process. The technology developed will enable better control over the casting process. It is expected to reduce scrap and variance in the casting quality. A strong educational component is integrated into the research plan to utilize increased awareness of the industry professional, the potential benefits of the developed technology, and the potential benefits of cross cutting technologies.

  3. Effect of low doses beta irradiation on micromechanical properties of surface layer of injection molded polypropylene composite

    Science.gov (United States)

    Manas, David; Manas, Miroslav; Gajzlerova, Lenka; Ovsik, Martin; Kratky, Petr; Senkerik, Vojt?ch; Skrobak, Adam; Danek, Michal; Manas, Martin

    2015-09-01

    The influence of beta radiation on the changes in the structure and selected properties (mechanical and thermal) was proved. Using low doses of beta radiation for 25% glass fiber filled polypropylene and its influence on the changes of micromechanical properties of surface layer has not been studied in detail so far. The specimens of 25% glass fiber filled PP were made by injection molding technology and irradiated by low doses of beta radiation (0, 15 and 33 kGy). The changes in the microstructure and micromechanical properties of surface layer were evaluated using FTIR, SEM, WAXS and instrumented microhardness test. The results of the measurements showed considerable increase in micromechanical properties (indentation hardness, indentation elastic modulus) when low doses of beta radiation are used.

  4. Embedded fiber optic sensors for monitoring processing, quality and structural health of resin transfer molded components

    Science.gov (United States)

    Keulen, C.; Rocha, B.; Yildiz, M.; Suleman, A.

    2011-07-01

    Due to their small size and flexibility fiber optics can be embedded into composite materials with little negative effect on strength and reliability of the host material. Fiber optic sensors such as Fiber Bragg Gratings (FBG) or Etched Fiber Sensors (EFS) can be used to detect a number of relevant parameters such as flow, degree of cure, quality and structural health throughout the life of a composite component. With a detection algorithm these embedded sensors can be used to detect damage in real time while the component remains in service. This paper presents the research being conducted on the use of fiber optic sensors for process and Structural Health Monitoring (SHM) of Resin Transfer Molded (RTM) composite structures. Fiber optic sensors are used at all life stages of an RTM composite panel. A laboratory scale RTM apparatus was developed with the capability of visually monitoring the resin filling process. A technique for embedding fiber optic sensors with this apparatus has also been developed. Both FBGs and EFSs have been embedded in composite panels using the apparatus. EFSs to monitor the fabrication process, specifically resin flow have been embedded and shown to be capable of detecting the presence of resin at various locations as it is injected into the mold. Simultaneously these sensors were multiplexed on the same fiber with FBGs, which have the ability to measure strain. Since multiple sensors can be multiplexed on a single fiber the number of ingress/egress locations required per sensor can be significantly reduced. To characterize the FBGs for strain detection tensile test specimens with embedded FBG sensors have been produced. These specimens have been instrumented with a resistive strain gauge for benchmarking. Both specimens and embedded sensors were characterized through tensile testing. Furthermore FBGs have been embedded into composite panels in a manner that is conducive to detection of Lamb waves generated with a centrally located PZT. To sense Lamb waves a high speed, high precision sensing technique is required to acquire data from embedded FBGs due to the high velocities and small strain amplitudes of these guided waves. A technique based on a filter consisting of a tunable FBG was developed. Since this filter is not dependant on moving parts, tests executed with this filter concluded with the detection of Lamb waves, removing the influence of temperature and operational strains. A damage detection algorithm was developed to detect and localize cracks and delaminations.

  5. Embedded fiber optic sensors for monitoring processing, quality and structural health of resin transfer molded components

    International Nuclear Information System (INIS)

    Due to their small size and flexibility fiber optics can be embedded into composite materials with little negative effect on strength and reliability of the host material. Fiber optic sensors such as Fiber Bragg Gratings (FBG) or Etched Fiber Sensors (EFS) can be used to detect a number of relevant parameters such as flow, degree of cure, quality and structural health throughout the life of a composite component. With a detection algorithm these embedded sensors can be used to detect damage in real time while the component remains in service. This paper presents the research being conducted on the use of fiber optic sensors for process and Structural Health Monitoring (SHM) of Resin Transfer Molded (RTM) composite structures. Fiber optic sensors are used at all life stages of an RTM composite panel. A laboratory scale RTM apparatus was developed with the capability of visually monitoring the resin filling process. A technique for embedding fiber optic sensors with this apparatus has also been developed. Both FBGs and EFSs have been embedded in composite panels using the apparatus. EFSs to monitor the fabrication process, specifically resin flow have been embedded and shown to be capable of detecting the presence of resin at various locations as it is injected into the mold. Simultaneously these sensors were multiplexed on the same fiber with FBGs, which have the ability to measure strain. Since multiple sensors can be multiplexed on a single fiber the number of ingress/egress locations required per sensor can be significantly reduced. To characterize the FBGs for strain detection tensile test specimens with embedded FBG sensors have been produced. These specimens have been instrumented with a resistive strain gauge for benchmarking. Both specimens and embedded sensors were characterized through tensile testing. Furthermore FBGs have been embedded into composite panels in a manner that is conducive to detection of Lamb waves generated with a centrally located PZT. To sense Lamb waves a high speed, high precision sensing technique is required to acquire data from embedded FBGs due to the high velocities and small strain amplitudes of these guided waves. A technique based on a filter consisting of a tunable FBG was developed. Since this filter is not dependant on moving parts, tests executed with this filter concluded with the detection of Lamb waves, removing the influence of temperature and operational strains. A damage detection algorithm was developed to detect and localize cracks and delaminations.

  6. Characterization of thermoplastic polyurethane/polylactic acid (TPU/PLA) tissue engineering scaffolds fabricated by microcellular injection molding

    Energy Technology Data Exchange (ETDEWEB)

    Mi, Hao-Yang [National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou (China); Department of Mechanical Engineering, University of Wisconsin–Madison, WI (United States); Salick, Max R. [Department of Engineering Physics, University of Wisconsin–Madison, WI (United States); Jing, Xin [National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou (China); Department of Mechanical Engineering, University of Wisconsin–Madison, WI (United States); Jacques, Brianna R. [Department of Biology, University of Wisconsin–River Falls, WI (United States); Crone, Wendy C. [Department of Engineering Physics, University of Wisconsin–Madison, WI (United States); Peng, Xiang-Fang, E-mail: pmxfpeng@scut.edu.cn [National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou (China); Turng, Lih-Sheng, E-mail: turng@engr.wisc.edu [Department of Mechanical Engineering, University of Wisconsin–Madison, WI (United States)

    2013-12-01

    Polylactic acid (PLA) and thermoplastic polyurethane (TPU) are two kinds of biocompatible and biodegradable polymers that can be used in biomedical applications. PLA has rigid mechanical properties while TPU possesses flexible mechanical properties. Blended TPU/PLA tissue engineering scaffolds at different ratios for tunable properties were fabricated via twin screw extrusion and microcellular injection molding techniques for the first time. Multiple test methods were used to characterize these materials. Fourier transform infrared spectroscopy (FTIR) confirmed the existence of the two components in the blends; differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) confirmed the immiscibility between the TPU and PLA. Scanning electron microscopy (SEM) images verified that, at the composition ratios studied, PLA was dispersed as spheres or islands inside the TPU matrix and that this phase morphology further influenced the scaffold's microstructure and surface roughness. The blends exhibited a large range of mechanical properties that covered several human tissue requirements. 3T3 fibroblast cell culture showed that the scaffolds supported cell proliferation and migration properly. Most importantly, this study demonstrated the feasibility of mass producing biocompatible PLA/TPU scaffolds with tunable microstructures, surface roughnesses, and mechanical properties that have the potential to be used as artificial scaffolds in multiple tissue engineering applications. - Highlights: • Microcellular injection molding was used to fabricate tissue engineering scaffolds. • TPU/PLA tissue engineering scaffolds with tunable properties were fabricated. • Multiple test methods were used to characterize the scaffolds. • The biocompatibility of the scaffolds was confirmed by fibroblast cell culture. • Scaffolds produced have the potential to be used in multiple tissue applications.

  7. Simulative design and process optimization of the two-stage stretch-blow molding process

    Energy Technology Data Exchange (ETDEWEB)

    Hopmann, Ch.; Rasche, S.; Windeck, C. [Institute of Plastics Processing at RWTH Aachen University (IKV) Pontstraße 49, 52062 Aachen (Germany)

    2015-05-22

    The total production costs of PET bottles are significantly affected by the costs of raw material. Approximately 70 % of the total costs are spent for the raw material. Therefore, stretch-blow molding industry intends to reduce the total production costs by an optimized material efficiency. However, there is often a trade-off between an optimized material efficiency and required product properties. Due to a multitude of complex boundary conditions, the design process of new stretch-blow molded products is still a challenging task and is often based on empirical knowledge. Application of current CAE-tools supports the design process by reducing development time and costs. This paper describes an approach to determine optimized preform geometry and corresponding process parameters iteratively. The wall thickness distribution and the local stretch ratios of the blown bottle are calculated in a three-dimensional process simulation. Thereby, the wall thickness distribution is correlated with an objective function and preform geometry as well as process parameters are varied by an optimization algorithm. Taking into account the correlation between material usage, process history and resulting product properties, integrative coupled simulation steps, e.g. structural analyses or barrier simulations, are performed. The approach is applied on a 0.5 liter PET bottle of Krones AG, Neutraubling, Germany. The investigations point out that the design process can be supported by applying this simulative optimization approach. In an optimization study the total bottle weight is reduced from 18.5?g to 15.5?g. The validation of the computed results is in progress.

  8. Simulative design and process optimization of the two-stage stretch-blow molding process

    Science.gov (United States)

    Hopmann, Ch.; Rasche, S.; Windeck, C.

    2015-05-01

    The total production costs of PET bottles are significantly affected by the costs of raw material. Approximately 70 % of the total costs are spent for the raw material. Therefore, stretch-blow molding industry intends to reduce the total production costs by an optimized material efficiency. However, there is often a trade-off between an optimized material efficiency and required product properties. Due to a multitude of complex boundary conditions, the design process of new stretch-blow molded products is still a challenging task and is often based on empirical knowledge. Application of current CAE-tools supports the design process by reducing development time and costs. This paper describes an approach to determine optimized preform geometry and corresponding process parameters iteratively. The wall thickness distribution and the local stretch ratios of the blown bottle are calculated in a three-dimensional process simulation. Thereby, the wall thickness distribution is correlated with an objective function and preform geometry as well as process parameters are varied by an optimization algorithm. Taking into account the correlation between material usage, process history and resulting product properties, integrative coupled simulation steps, e.g. structural analyses or barrier simulations, are performed. The approach is applied on a 0.5 liter PET bottle of Krones AG, Neutraubling, Germany. The investigations point out that the design process can be supported by applying this simulative optimization approach. In an optimization study the total bottle weight is reduced from 18.5 g to 15.5 g. The validation of the computed results is in progress.

  9. Simulative design and process optimization of the two-stage stretch-blow molding process

    International Nuclear Information System (INIS)

    The total production costs of PET bottles are significantly affected by the costs of raw material. Approximately 70 % of the total costs are spent for the raw material. Therefore, stretch-blow molding industry intends to reduce the total production costs by an optimized material efficiency. However, there is often a trade-off between an optimized material efficiency and required product properties. Due to a multitude of complex boundary conditions, the design process of new stretch-blow molded products is still a challenging task and is often based on empirical knowledge. Application of current CAE-tools supports the design process by reducing development time and costs. This paper describes an approach to determine optimized preform geometry and corresponding process parameters iteratively. The wall thickness distribution and the local stretch ratios of the blown bottle are calculated in a three-dimensional process simulation. Thereby, the wall thickness distribution is correlated with an objective function and preform geometry as well as process parameters are varied by an optimization algorithm. Taking into account the correlation between material usage, process history and resulting product properties, integrative coupled simulation steps, e.g. structural analyses or barrier simulations, are performed. The approach is applied on a 0.5 liter PET bottle of Krones AG, Neutraubling, Germany. The investigations point out that the design process can be supported by applying this simulative optimization approach. In an optimization study the total bottle weight is reduced from 18.5?g to 15.5?g. The validation of the computed results is in progress

  10. Silane based coating of aluminium mold

    DEFF Research Database (Denmark)

    Cech, Jiri Technical University of Denmark,

    A method of preparing an aluminum mold for injection molding is provided, the method comprises the steps of providing an aluminum mold having a least one surface, subjecting the at least one surface to a gas or liquid phase silane to thereby form an anti-stiction coating, the anti-stiction coating comprising a chemically bonded monolayer of silane compounds on the at least one surface wherein the silane is a halogenated silane. The at least one surface coated with the anti-stiction coating may be configured to withstand an injection molding process at a pressure above 100 MPa. Furthermore, a mold having at least one closed cavity is provided, at least one surface of the at least one cavity being an aluminium surface coated with a silane based coating layer. The silane based anti-stiction coating improves the anti-stiction properties of the mold which may allow for molding and demolding of structures which would otherwise be difficult to mold. The resistance of the coated aluminium mold is significantly improved by applying a silane-based coating layer.

  11. Extruded/injection-molded composites containing unripe plantain flour, ethylene vinyl-alcohol and glycerol: Evaluation of color, mechanical property and biodegradability

    Science.gov (United States)

    Extruded/injection-molded composites were produced from plantain flour blended with ethylene vinyl-alcohol (EVA) and glycerol. Scanning electron microscopy showed composites had a smooth surface and excellent compatibility between plantain flour, EVA and glycerol. The impact of increased plantain fl...

  12. Visual analysis of silver-streak generation process by glass-inserted mold. Glass insert kanagata ni yoru silver steak seisei katei no kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Murata, Y.; Yokoi, H. (The University of Tokyo, Tokyo (Japan). Institute of Industrial Science); Nagaya, M. (Fanuc Ltd., Yamanashi (Japan)); Nagami, S. (Mitui Petrochemical Industries, Ltd., Tokyo (Japan)); Watanabe, H. (Munekata Co. Ltd., Osaka (Japan))

    1993-06-01

    Silver-streak generation process in injection molding is discussed using a glass-inserted mold. Flow behavior of resin in a mold was photoed by using a high-speed video system. Surface shapes at silver-streak generated locations were observed using an electron microscope and a tool microscope. The following matters were verified: The silver-streaks can be divided into three kinds consisting of one that is formed at a moment when air bubbles having flown in resin from behind catch up its flow tip and make a fountain-flow; another that is formed from single large air bubble on one side or both sides of a formed product; and still another that is generated radially from a large number of fine air bubbles. These distinctions do not depend upon air-bubble generation causing substances. It was also found that, in the result of observation using a visualized heating cylinder, air bubbles generated in the heating cylinder once disappear as a result of risen cylinder internal pressure at an injection, and reappear as a result of decreased pressure in the mold. 7 refs., 9 figs., 2 tabs.

  13. High solid loading aqueous base metal/ceramic feedstock for injection molding

    Science.gov (United States)

    Behi, Mohammad

    2001-07-01

    Increasing volume fraction of metal powder in feedstock provided lower shrinkage. Reduction of the shrinkage results in better dimensional precision. The rheology of the feedstock material plays an important role to allowing larger volume fractions of the metal powder to be incorporated in the feedstock formulations. The viscosity of the feedstock mainly depends on the binder viscosity, powder volume fraction and characteristics of metal powder. Aqueous polysaccharide agar was used as a baseline binder system for this study. The effect of several gel-strengthening additives on 1.5wt% and 2wt% agar gel was evaluated. A new gel-strengthening additive was found to be the most effective among the others. The effect of other additives such as glucose, sucrose and fructose on viscosity of baseline binder and feedstock was investigated. Two new agar based binder compositions were developed. The use of these new binder formulations significantly improved the volume fraction of the metal powder, the stability of the feedstock, and reduced the final shrinkage of the molded articles. Two types of 17-4PH stainless steel metal powders, one gas atomized and, the other water atomized, were used for this research.

  14. Mold Allergy

    Science.gov (United States)

    Mold Allergy Mold Allergy Overview Symptoms & Diagnosis Treatment & Management Mold Allergy Overview Molds are tiny fungi whose spores float through the ... with others. Join us on Facebook and Twitter . Mold Allergy Symptoms & Diagnosis Symptoms Many people allergic to ...

  15. Development of ACP reinforced thermoplastic composites as an alternative to open mold processing

    Science.gov (United States)

    O'Neill, Michael A.

    1992-01-01

    Thermoplastic/foam/glass composite technology provides a method of producing large structural parts without styrene or volatile organic compounds (VOCs). High-quality parts can be molded at a low cost by combining vacuum forming technology with a low-pressure urethane reinforcement technique. This process eliminates atomization of paint or gelcoats, styrene emissions from FRP, and associated solvents and chemicals required in the normal processing of fiberglass. Secondary operations also can be streamlined by parts consolidation in the reinforcement process.

  16. Investigations on Void Formation in Composite Molding Processes and Structural Damping in Fiber-Reinforced Composites with Nanoscale Reinforcements

    Science.gov (United States)

    DeValve, Caleb Joshua

    Fiber-reinforced composites (FRCs) offer a stronger and lighter weight alternative to traditional materials used in engineering components such as wind turbine blades and rotorcraft structures. Composites for these applications are often fabricated using liquid molding techniques, such as injection molding or resin transfer molding. One significant issue during these processing methods is void formation due to incomplete wet-out of the resin within the fiber preform, resulting in discontinuous material properties and localized failure zones in the material. A fundamental understanding of the resin evolution during processing is essential to designing processing conditions for void-free filling, which is the first objective of the dissertation. Secondly, FRCs used in rotorcraft experience severe vibrational loads during service, and improved damping characteristics of the composite structure are desirable. To this end, a second goal is to explore the use of matrix-embedded nanoscale reinforcements to augment the inherent damping capabilities in FRCs. The first objective is addressed through a computational modeling and simulation of the infiltrating dual-scale resin flow through the micro-architectures of woven fibrous preforms, accounting for the capillary effects within the fiber bundles. An analytical model is developed for the longitudinal permeability of flow through fibrous bundles and applied to simulations which provide detailed predictions of local air entrapment locations as the resin permeates the preform. Generalized design plots are presented for predicting the void content and processing time in terms of the Capillary and Reynolds Numbers governing the molding process. The second portion of the research investigates the damping enhancement provided to FRCs in static and rotational configurations by different types and weight fractions of matrix-embedded carbon nanotubes (CNTs) in high fiber volume fraction composites. The damping is measured using dynamic mechanical analysis (DMA) and modal analysis techniques, and the results show that the addition of CNTs can increase the material damping by up to 130%. Numerical simulations are conducted to explore the CNT vibration damping effects in rotating composite structures, and demonstrate that the vibration settling times and the maximum displacement amplitudes of the different structures may be reduced by up to 72% and 50%, respectively, with the addition of CNTs.

  17. Processing integral-skin polyolefin foams in single-charge rotational foam molding

    Science.gov (United States)

    Pop-Iliev, Remon

    This thesis focuses on establishing the scientific and engineering foundations for gaining a fundamental understanding of the mechanisms and critical parameters governing the processing of integral-skin low-density polyolefin foams in rotational foam molding. The presented research is particularly intended to broaden the knowledge in the field of manufacturing adjacent, but clearly distinct, layers of non-cellular and cellular structures, consisting of identical or compatible plastic grades, using a single-charge processing concept. Although this technology is beneficial for the efficacy of the molding process and the structural homogeneity of the moldings, its optimization raised a fairly large number of fundamental issues that had to be resolved through further research. In this context, an attempt has been made to establish rigorous, experimentally validated, theoretical models that describe the phenomena identified as the fundamental challenges of this technology. The major contributions of this thesis include: (i) optimization of the single-charge rotational foam molding process for the manufacture of both PE/PE and PE/PP integral-skin cellular composites, (ii) development of a two-step oven temperature profile that prevents the foamable resins invading the solid skin layer and ensures that skin formation always completes prior to the activation of the foamable resin, (iii) fundamental study of the adherence behavior of powders and foamable pellets to a high-temperature rotating mold wall, (iv) fundamental study of the lifespan of CBA-blown bubbles in non-pressurized non-isothermal polymer melts using hot-stage optical microscopy and digital imaging, (v) development of a detailed theoretical model involving diffusion, surface tension, and viscosity to simulate the observed foaming mechanism, and (vi) fundamental study of the rotofoamablility of polyolefin resins using both dry blending and melt compounding based methods and characterization of rheological and thermal properties.

  18. An Approach to Rib Design of Injection Molded Product Using Finite Element and Taguchi Method

    OpenAIRE

    Tian-Syung Lan; Min-Chie Chiu; Long-Jyi Yeh

    2008-01-01

    In this study, not only Taguchi Method but also ANSYS in providing an economical and effective advance to the optimum design of the rib for a plastic injected product are introduced. The analytical model of a rectangular thermoplastic Acrylonitrile Butadiene Styrene (ABS) plastic cover with rib of given thickness (2.8 mm) was selected and constructed based on design experiences and the dimensions as well as the width of the rib were selected as the control factors for Taguchi Method. The defl...

  19. Survey of molds, yeast and Alicyclobacillus spp. from a concentrated apple juice productive process

    Scientific Electronic Library Online (English)

    Beatriz de Cássia Martins, Salomão; Chalana, Muller; Hudson Couto do, Amparo; Gláucia Maria Falcão de, Aragão.

    Full Text Available Bacteria and molds may spoil and/or contaminate apple juice either by direct microbial action or indirectly by the uptake of metabolites as off-flavours and toxins. Some of these microorganisms and/or metabolites may remain in the food even after extensive procedures. This study aim to identify the [...] presence of molds (including heat resistant species) and Alicyclobacillus spp., during concentrated apple juice processing. Molds were isolated at different steps and then identified by their macroscopic and microscopic characteristics after cultivation on standard media at 5, 25 and 37ºC, during 7 days. Among the 19 isolated found, 63% were identified as Penicillium with 50% belonging to the P. expansum specie. With regards to heat resistant molds, the species Neosartorya fischeri, Byssochlamys fulva and also the genus Eupenicillium sp., Talaromyces sp. and Eurotium sp. were isolated. The thermoacidophilic spore-forming bacteria were identified as A. acidoterrestris by a further investigation based on 16S rRNA sequence similarity. The large contamination found indicates the need for methods to eliminate or prevent the presence of these microorganisms in the processing plants in order to avoid both spoilage of apple juice and toxin production.

  20. Survey of molds, yeast and Alicyclobacillus spp. from a concentrated apple juice productive process

    Directory of Open Access Journals (Sweden)

    Beatriz de Cássia Martins Salomão

    2014-01-01

    Full Text Available Bacteria and molds may spoil and/or contaminate apple juice either by direct microbial action or indirectly by the uptake of metabolites as off-flavours and toxins. Some of these microorganisms and/or metabolites may remain in the food even after extensive procedures. This study aim to identify the presence of molds (including heat resistant species and Alicyclobacillus spp., during concentrated apple juice processing. Molds were isolated at different steps and then identified by their macroscopic and microscopic characteristics after cultivation on standard media at 5, 25 and 37ºC, during 7 days. Among the 19 isolated found, 63% were identified as Penicillium with 50% belonging to the P. expansum specie. With regards to heat resistant molds, the species Neosartorya fischeri, Byssochlamys fulva and also the genus Eupenicillium sp., Talaromyces sp. and Eurotium sp. were isolated. The thermoacidophilic spore-forming bacteria were identified as A. acidoterrestris by a further investigation based on 16S rRNA sequence similarity. The large contamination found indicates the need for methods to eliminate or prevent the presence of these microorganisms in the processing plants in order to avoid both spoilage of apple juice and toxin production.

  1. Survey of molds, yeast and Alicyclobacillus spp. from a concentrated apple juice productive process.

    Science.gov (United States)

    de Cássia Martins Salomão, Beatriz; Muller, Chalana; do Amparo, Hudson Couto; de Aragão, Gláucia Maria Falcão

    2014-01-01

    Bacteria and molds may spoil and/or contaminate apple juice either by direct microbial action or indirectly by the uptake of metabolites as off-flavours and toxins. Some of these microorganisms and/or metabolites may remain in the food even after extensive procedures. This study aim to identify the presence of molds (including heat resistant species) and Alicyclobacillus spp., during concentrated apple juice processing. Molds were isolated at different steps and then identified by their macroscopic and microscopic characteristics after cultivation on standard media at 5, 25 and 37 °C, during 7 days. Among the 19 isolated found, 63% were identified as Penicillium with 50% belonging to the P. expansum specie. With regards to heat resistant molds, the species Neosartorya fischeri, Byssochlamys fulva and also the genus Eupenicillium sp., Talaromyces sp. and Eurotium sp. were isolated. The thermoacidophilic spore-forming bacteria were identified as A. acidoterrestris by a further investigation based on 16S rRNA sequence similarity. The large contamination found indicates the need for methods to eliminate or prevent the presence of these microorganisms in the processing plants in order to avoid both spoilage of apple juice and toxin production. PMID:24948913

  2. Fabrication and characterization of poly(propylene fumarate) scaffolds with controlled pore structures using 3-dimensional printing and injection molding.

    Science.gov (United States)

    Lee, Kee-Won; Wang, Shanfeng; Lu, Lichun; Jabbari, Esmaiel; Currier, Bradford L; Yaszemski, Michael J

    2006-10-01

    Poly(propylene fumarate) (PPF) is an injectable, biodegradable polymer that has been used for fabricating preformed scaffolds in tissue engineering applications because of in situ crosslinking characteristics. Aiming for understanding the effects of pore structure parameters on bone tissue ingrowth, 3-dimensional (3D) PPF scaffolds with controlled pore architecture have been produced in this study from computer-aided design (CAD) models. We have created original scaffold models with 3 pore sizes (300, 600, and 900 microm) and randomly closed 0%, 10%, 20%, or 30% of total pores from the original models in 3 planes. PPF scaffolds were fabricated by a series steps involving 3D printing of support/build constructs, dissolving build materials, injecting PPF, and dissolving support materials. To investigate the effects of controlled pore size and interconnectivity on scaffolds, we compared the porosities between the models and PPF scaffolds fabricated thereby, examined pore morphologies in surface and cross-section using scanning electron microscopy, and measured permeability using the falling head conductivity test. The thermal properties of the resulting scaffolds as well as uncrosslinked PPF were determined by differential scanning calorimetry and thermogravimetric analysis. Average pore sizes and pore shapes of PPF scaffolds with 600- and 900-microm pores were similar to those of CAD models, but they depended on directions in those with 300-microm pores. Porosity and permeability of PPF scaffolds decreased as the number of closed pores in original models increased, particularly when the pore size was 300 microm as the result of low porosity and pore occlusion. These results show that 3D printing and injection molding technique can be applied to crosslinkable polymers to fabricate 3D porous scaffolds with controlled pore structures, porosity, and permeability using their CAD models. PMID:17518649

  3. Interface conditions of two-shot molded parts

    Energy Technology Data Exchange (ETDEWEB)

    Kisslinger, Thomas, E-mail: thomas.kisslinger@pccl.at [Polymer Competence Center Leoben GmbH, 8700 Leoben (Austria); Bruckmoser, Katharina, E-mail: katharina.bruckmoser@unileoben.ac.at; Resch, Katharina, E-mail: katharina.resch@unileoben.ac.at [Department of Polymer Engineering and Science, Chair of Materials Science and Testing of Polymers, Montanuniversitaet Leoben, 8700 Leoben (Austria); Lucyshyn, Thomas, E-mail: thomas.lucyshyn@unileoben.ac.at, E-mail: guenter.langecker@unileoben.ac.at; Langecker, Guenter Ruediger, E-mail: thomas.lucyshyn@unileoben.ac.at, E-mail: guenter.langecker@unileoben.ac.at; Holzer, Clemens, E-mail: clemens.holzer@unileoben.ac.at [Department of Polymer Engineering and Science, Chair of Polymer Processing, Montanuniversitaet Leoben, 8700 Leoben (Austria)

    2014-05-15

    The focus of this work is on interfaces of two-shot molded parts. It is well known that e.g. material combination, process parameters and contact area structures show significant effects on the bond strength of multi-component injection molded parts. To get information about the bond strength at various process parameter settings and material combinations a test mold with core back technology was used to produce two-component injection molded tensile test specimens. At the core back process the different materials are injected consecutively, so each component runs through the whole injection molding cycle (two-shot process). Due to this consecutive injection molding processes, a cold interface is generated. This is defined as overmolding of a second melt to a solidified polymer preform. Strong interest lies in the way the interface conditions change during the adhesion formation between the individual components. Hence the interface conditions were investigated by computed tomography and Raman spectroscopy. By analyzing these conditions the understanding of the adhesion development during the multi-component injection molding was improved.

  4. An Approach to Rib Design of Injection Molded Product Using Finite Element and Taguchi Method

    Directory of Open Access Journals (Sweden)

    Tian-Syung Lan

    2008-01-01

    Full Text Available In this study, not only Taguchi Method but also ANSYS in providing an economical and effective advance to the optimum design of the rib for a plastic injected product are introduced. The analytical model of a rectangular thermoplastic Acrylonitrile Butadiene Styrene (ABS plastic cover with rib of given thickness (2.8 mm was selected and constructed based on design experiences and the dimensions as well as the width of the rib were selected as the control factors for Taguchi Method. The deflection under a constant force of 150 Newton at the back centre of the cover was defined as quality characteristic. Additionally, the deformation experiment on a fixed thin beam was compared with the analytical result from ANSYS to verify the reliability of structure analysis from associated parameter setup and boundary condition operation. The L9(34 orthogonal array from Taguchi Method was moreover arranged to establish nine sets of finite element analysis models. Through Taguchi Method, the optimum design parameters were furthermore received from minimum deformation at back centre of the plastic cover analyzed by ANSYS. It is shown that the optimum structural parameters of a plastic rib can surely be effectively found with the integration of both Taguchi Method and ANSYS. Therefore, an Expert System of optimum design for various shapes of ribs can then be constructed through this study. This study exactly contributes a novel technique to the rib design for plastic injection industry in minimizing the development period of a new product.

  5. Influence of injection molding on the electrical properties of polyamide 12 filled with multi-walled carbon nanotubes

    OpenAIRE

    VERSAVAUD, Sophie; Regnier, Gilles; Gouadec, Gwénaël; Vincent, Michel

    2014-01-01

    Microinjection-molded and compression-molded polyamide (PA12) matrix composites filled with 0.67, 1.33, 2 and 4 wt% multi-walled carbon nanotubes (MWNTs) were prepared from twin-screw extruded pellets. The compression molded samples have an electrical percolation threshold close to 1.2 wt%. Coupled rheological and electrical measurements show that their electrical properties start decreasing as soon as shear begins and are partially restored during flow, suggesting successively breakage and r...

  6. 2:17-type SmCo magnets prepared by powder injection molding using a water-based binder

    Science.gov (United States)

    Tian, Jianjun; Tao, Siwu; Qu, Xuanhui; Zhang, Shengen

    2:17-type SmCo permanent magnets by powder injection molding using a water-based binder have been studied. The water-based binder is methylcellulose solution, which consists of deionized water and methylcellulose. When the solution concentration is 0.5 wt%, the carbon content of the sintered magnets is below 0.1 wt% and the magnets have better magnetic properties. The magnetic properties and density of the sintered magnets can be increased through pre-sintering in vacuum (10 -3 Pa) at 1200 °C. However, the Sm content of the magnets loses obviously in pre-sintering for a long period. The appropriate pre-sintering duration is 20-40 min. The magnetic properties of the magnets are: Br=0.97 T, Hcj=871 kA/m, BH max=157 kJ/m 3. The structure of the magnet consists of the matrix phases (2:17 phases) and the precipitate phases (1:5 phases).

  7. AKUMULASI LISTRIK STATIS PADA GELAS PLASTIK PRODUKSI MESIN INJECTION MOLDING: PENGARUH KELEMBABAN UDARA, TEMPERATUR, DAN BAHAN ADITIF

    Directory of Open Access Journals (Sweden)

    Ratnawati Ratnawati

    2014-12-01

    Full Text Available Akumulasi listrik statis pada gelas polipropilena hasil produksi mesin injection molding dapat menyebabkan gelas memiliki gaya elektrostatik dan tidak dapat turun secara gravitasi. Masalah ini menghambat aplikasi gelas pada mesin pengisian air minum dalam kemasan (AMDK. Penelitian ini bertujuan untuk mengetahui pengaruh kelembaban udara, temperatur, dan penambahan bahan aditif TiO2 terhadap potensial listrik permukaan gelas polipropilena. Hasil penelitian menunjukkan bahwa potensial listrik permukaan dipengaruhi oleh kelembaban udara ruang produksi, temperatur, dan penambahan TiO2. Potensial listrik permukaan semakin kecil dengan naiknya kelembaban udara. Setelah kelembaban mencapai 68% potensial listrik permukaan cenderung konstan. Ditinjau dari beda potensial (DV antara permukaan dua gelas, kelembaban optimum adalah 67-68%, yang ditandai dengan beda potensial yang paling rendah. Beda potensial ? 5,2 kV menyebabkan gelas cepat turun, beda potensial 5,2 kV < DV ? 6,7 kV menyebabkan gelas turun dengan lambat, dan DV ? 6,7 kV menyebabkan gelas sangat lambat turun atau menempel. Potensial listrik turun dengan naiknya temperatur. Potensial listrik statis permukaan hanya sedikit turun akibat penambahan 0,75% berat TiO2. Hasil penelitian ini juga menunjukkan bahwa penggunaan gelas dengan potensial listrik permukaan rendah dapat menaikkan kecepatan mesin pengisian AMDK menjadi 220-250 rpm dan 140-160 rpm, masing-masing untuk mesin pengisian gelas 180 ml dan 225 ml.

  8. 2:17-type SmCo magnets prepared by powder injection molding using a water-based binder

    Energy Technology Data Exchange (ETDEWEB)

    Tian Jianjun [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, Beijing 100083 (China)], E-mail: tianjianjun@mater.ustb.edu.cn; Tao Siwu [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Qu Xuanhui [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, Beijing 100083 (China); Zhang Shengen [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2008-09-15

    2:17-type SmCo permanent magnets by powder injection molding using a water-based binder have been studied. The water-based binder is methylcellulose solution, which consists of deionized water and methylcellulose. When the solution concentration is 0.5 wt%, the carbon content of the sintered magnets is below 0.1 wt% and the magnets have better magnetic properties. The magnetic properties and density of the sintered magnets can be increased through pre-sintering in vacuum (10{sup -3} Pa) at 1200 deg. C. However, the Sm content of the magnets loses obviously in pre-sintering for a long period. The appropriate pre-sintering duration is 20-40 min. The magnetic properties of the magnets are: Br=0.97 T, H{sub cj}=871 kA/m, BH{sub max}=157 kJ/m{sup 3}. The structure of the magnet consists of the matrix phases (2:17 phases) and the precipitate phases (1:5 phases)

  9. 2:17-type SmCo magnets prepared by powder injection molding using a water-based binder

    International Nuclear Information System (INIS)

    2:17-type SmCo permanent magnets by powder injection molding using a water-based binder have been studied. The water-based binder is methylcellulose solution, which consists of deionized water and methylcellulose. When the solution concentration is 0.5 wt%, the carbon content of the sintered magnets is below 0.1 wt% and the magnets have better magnetic properties. The magnetic properties and density of the sintered magnets can be increased through pre-sintering in vacuum (10-3 Pa) at 1200 deg. C. However, the Sm content of the magnets loses obviously in pre-sintering for a long period. The appropriate pre-sintering duration is 20-40 min. The magnetic properties of the magnets are: Br=0.97 T, Hcj=871 kA/m, BHmax=157 kJ/m3. The structure of the magnet consists of the matrix phases (2:17 phases) and the precipitate phases (1:5 phases)

  10. Mechanical and thermal properties of conventional and microcellular injection molded poly (lactic acid)/poly (?-caprolactone) blends.

    Science.gov (United States)

    Zhao, Haibin; Zhao, Guoqun

    2016-01-01

    In view of their complementary properties, blending polylactide (PLA) with poly (?-caprolactone) (PCL) becomes a good choice to improve PLA's properties without compromising its biodegradability. A series of blends of biodegradable PLA and PCL with different mass fraction were prepared by melt mixing. Standard tensile bars were produced by both conventional and microcellular injection molding to study their mechanical and thermal properties. With the increase in PCL content, the blend showed decreased tensile strength and modulus; however, elongation was dramatically increased. With the addition of PCL, the failure mode changed from brittle fracture of the neat PLA to ductile fracture of the blend as demonstrated by tensile test. Various theoretical models based on dispersion and interface adhesion were used to predict the Young's modulus and the results shows the experimental data are consistent with the predictions of the foam model and Kerner-Uemura-Takayangi model. The thermal behavior of the blends was investigated by DSC and TGA. The melting temperature and the degree of crystallinity of PCL in the PLA/PCL did not significantly change with the PCL content increasing in the whole range of blends composition. PMID:26313249

  11. Fabrication of double-sided micro structured mechanical sensors based on SU-8 resist using a new micro molding process

    Science.gov (United States)

    Oerke, A.; Büttgenbach, S.; Dietzel, A.

    2013-05-01

    Advances in micro and nano fabrication technologies for MEMS require high-level measurement techniques with regard to sampling and sensitivity. For this purpose at the Institute of Microtechnology (IMT) highly sensitive piezoresistive 3D force sensors based on SU-8 polymer have been developed. In this paper we present an improved micro fabrication process for a double-sided micro structured design. The sensors are produced by multilayer processing techniques such as UV lithography and coating methods. The double-sided micro structured design demands a photoresist application method which simultaneously features a top side structuring and a casting from a mold. We use a new micro molding process to meet the demands. The micro fabrication technology is described, focusing on the development of the molding structure for shaping of the bottom side and a capable release process for the detachment of the molded structures. The fabrication process of the SU-8 mold layer is optimized to fabricate molding structures with heights from a few ?m up to 350 ?m. Therefore different SU-8 formulations, namely with classification numbers 5, 25, 50, and 100, have been used. The fundamental limitations for the mold design result from the lithography process, which defines the smallest lateral resolution, and from the characteristics of a molding process, e. g. the impossibility to realize an undercut. To allow for reliable release, the molding structures have to be coated with a sacrificial layer. A silicon nitride is deposited onto the substrate with an accompanying monitoring of the deposition temperature during the PECVD process.

  12. Mold production for polymer optics

    Science.gov (United States)

    Boerret, Rainer; Raab, Jonas; Speich, Marco

    2014-09-01

    The fields of application for polymer optics are huge and thus the need for polymer optics is steadily growing. Most polymer optics are produced in high numbers by injection molding. Therefore molds and dies that fulfill special requirements are needed. Polishing is usually the last process in the common process chain for production of molds for polymer optics. Usually this process step is done manually by experienced polishers. Due to the small number of skilled professionals and health problems because of the monotonous work the idea was to support or probably supersede manual polishing. Polishing using an industrial robot as movement system enables totally new possibilities in automated polishing. This work focuses on the surface generation with a newly designed polishing setup and on the code generation for the robot movement. The process starts on ground surfaces and with different tools and polishing agents surfaces that fulfill the requirements for injection molding of optics can be achieved. To achieve this the attention has to be focused not only on the process itself but also on tool path generation. A proprietary software developed in the Centre for Optical Technologies in Aalen University allows the tool path generation on almost any surface. This allows the usage of the newly developed polishing processes on different surfaces and enables an easy adaption. Details of process and software development will be presented as well as results from different polishing tests on different surfaces.

  13. Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - FY 2014 First Quarterly Report

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep; Sanborn, Scott E.; Simmons, Kevin L.; Mathur, Raj N.; Sangid, Michael D.; Jin, Xiaoshi; Costa, Franco; Gandhi, Umesh N.; Mori, Steven; Tucker III, Charles L.

    2014-02-19

    The CRADA between PNNL, Autodesk, Toyota and Magna has been effective since October 28th, 2013. The whole team including CRADA and subcontract partners kicked off the project technically on November 1st, 2013. This report describes work performed during the first quarter of FY 2014. The following technical progresses have been made toward project milestones: 1) The project kickoff meeting was organized at PlastiComp, Inc. in Winona on November 13th, 2013 involving all the project partners. During this meeting the research plan and Gantt chart were discussed and refined. The coordination of the research activities among the partners was also discussed to ensure that the deliverables and timeline will be met. 2) Autodesk delivered a research version of ASMI to PNNL for process modeling using this tool under the project. PNNL installed this research version on a PNNL computer and tested it. Currently, PNNL is using ASMI to prepare the models for PlastiComp plaques. 3) PlastiComp has compounded long carbon-fiber reinforced polypropylene and polyamide 6,6 compounds for rheological and thermal characterization tests by the Autodesk laboratories in Melbourne, Australia. 4) Initial mold flow analysis was carried out by PlastiComp to confirm that the 3D complex part selected by Toyota as a representative automotive part is moldable. 5) Toyota, Magna, PlastiComp and PNNL finalized the planning for molding the Toyota 3D complex part. 6) Purdue University worked with PNNL to update and specify the test matrix for characterization of fiber length/orientation. 7) Purdue University developed tools to automate the data collection and analysis of fiber length and orientation measurements. 8) Purdue University designed and specified equipment to replace the need for equipment using the technology established by the University of Leeds at General Motors.

  14. A New Fiber Preform with Nanocarbon Binder for Manufacturing Carbon Fiber Reinforced Composite by Liquid Molding Process.

    Science.gov (United States)

    Seong, Dong Gi; Ha, Jong Rok; Lee, Jea Uk; Lee, Wonoh; Kim, Byung Sun

    2015-11-01

    Carbon fiber reinforced composite has been a good candidate of lightweight structural component in the automotive industry. As fast production speed is essential to apply the composite materials for the mass production area such as automotive components, the high speed liquid composite molding processes have been developed. Fast resin injection through the fiber preform by high pressure is required to improve the production speed, but it often results in undesirable deformations of the fiber preform which causes defectives in size and properties of the final composite products. In order to prevent the undesirable deformation and improve the stability of preform shape, polymer type binder materials are used. More stable fiber preform can be obtained by increasing the amount of binder material, but it disturbs the resin impregnation through the fiber preform. In this study, carbon nanomaterials such as graphene oxide were embedded on the surface of carbon fiber by electrophoretic deposition method in order to improve the shape stability of fiber preform and interfacial bonding between polymer and the reinforcing fiber. Effects of the modified reinforcing fiber were investigated in two respects. One is to increase the binding energy between fiber tows, and the other is to increase the interfacial bonding between polymer matrix and fiber surface. The effects were analyzed by measuring the binding force of fiber preform and interlaminar shear strength of the composite. This study also investigated the high speed liquid molding process of the composite materials composed of polymer matrix and the carbon fiber preforms embedded by carbon nanomaterials. Process parameter such as permeability of fiber preform was measured to investigate the effect of nanoscale surface modification on the macroscale processing condition for composite manufacturing. PMID:26726642

  15. Hybrid tooling technologies and standardization for the manufacturing of inserts for micro injection molding

    DEFF Research Database (Denmark)

    Tosello, Guido; Fillon, Bertrand; Azcarate, Sabino; Schoth, Andreas; Mattsson, Lars; Griffiths, Christian; Staemmler, Lutz; Bolt, Pieter J.

    2007-01-01

    This paper is based on the European Platform’s activities within the 4M Network of Excellence “Multi-Material Micro Manufacturing”. To overpass limitations of the current existing micro tooling capabilities, a new generation of micro hybrid tooling technologies for micro replication was developed. A metrological approach was applied to standardize the employed tooling processes (micro milling, µEDM, laser micromachining, electrochemical µ-milling). The micro tools were then tested with different...

  16. Multidisciplinary design and optimization of a plastic injection mold using an integrated design and engineering environment:

    OpenAIRE

    Van Dijk, R.E.C.; d’Ippolito, R.; Tosi, G.; La Rocca, G.

    2011-01-01

    In order to remain competitive with respect to low-cost overseas markets, domestic moldmakers will have to increase the productivity of their engineers and maintain high quality standard, while dealing with the problem of an aging workforce. To increase the competitiveness of the European automotive industry, the concept of and Integrated Design and Engineering Environment (IDEE) has been developed within the 6th framework European project Pegasus - Integrated engineering processing & materia...

  17. Matrix Characterization and Development for the Vacuum Assisted Resin Transfer Molding Process

    Science.gov (United States)

    Grimsley, B. W.; Hubert, P.; Hou, T. H.; Cano, R. J.; Loos, A. C.; Pipes, R. B.

    2001-01-01

    The curing kinetics and viscosity of an epoxy resin system, SI-ZG-5A, have been characterized for application in the vacuum assisted resin transfer molding (VARTM) process. Impregnation of a typical carbon fiber perform provided the test bed for the characterization. Process simulations were carried out using the process model, COMPRO, to examine heat transfer and curing kinetics for a fully impregnated panel, neglecting resin flow. The predicted viscosity profile and final degree of cure were found to be in good agreement with experimental observations.

  18. Creating Drug Solubilization Compartments via Phase Separation in Multicomponent Buccal Patches Prepared by Direct Hot Melt Extrusion-Injection Molding.

    Science.gov (United States)

    Alhijjaj, Muqdad; Bouman, Jacob; Wellner, Nikolaus; Belton, Peter; Qi, Sheng

    2015-12-01

    Creating in situ phase separation in solid dispersion based formulations to allow enhanced functionality of the dosage form, such as improving dissolution of poorly soluble model drug as well as being mucoadhesive, can significantly maximize the in vitro and in vivo performance of the dosage form. This formulation strategy can benefit a wide range of solid dosage forms for oral and alternative routes of delivery. This study using buccal patches as an example created separated phases in situ of the buccal patches by selecting the excipients with different miscibility with each other and the model drug. The quaternary dispersion based buccal patches containing PEG, PEO, Tween 80, and felodipine were prepared by direct hot melt extrusion-injection molding (HME-IM). The partial miscibility between Tween 80 and semicrystalline PEG-PEO led to the phase separation after extrusion. The Tween phases acted as drug solubilization compartments, and the PEG-PEO phase had the primary function of providing mucoadhesion and carrier controlled dissolution. As felodipine was preferably solubilized in the amorphous regions of PEG-PEO, the high crystallinity of PEG-PEO resulted in an overall low drug solubilizing capacity. Tween 80 was added to improve the solubilization capacity of the system as the model drug showed good solubility in Tween. Increasing the drug loading led to the supersaturation of drug in Tween compartments and crystalline drug dispersed in PEG-PEO phases. The spatial distribution of these phase-separated compartments was mapped using X-ray micro-CT, which revealed that the domain size and heterogeneity of the phase separation increased with increasing the drug loading. The outcome of this study provides new insights into the applicability of in situ formed phase separation as a formulation strategy for the delivery of poorly soluble drugs and demonstrated the basic principle of excipient selection for such technology. PMID:26551593

  19. Optimization of the replica molding process of PDMS using pennate diatoms

    Science.gov (United States)

    Hlúbiková, D.; Luís, A. T.; Vaché, V.; Ector, L.; Hoffmann, L.; Choquet, P.

    2012-11-01

    Biomimetic fabrication of nanostructured materials has recently attracted the attention of researchers as a cost-effective and easily applicable method of nanotexturing. Different techniques and materials have been used in order to replicate natural patterns, among which polydimethylsiloxane (PDMS Sylgard 184®) was recently used to replicate the micro- and nanoscale patterns from centric diatoms. In this paper, we test the reproducibility and precision of this approach using various morphologically different diatom species trying to optimize the molding parameters. The optimization process is focused on immobilization of diatoms on the glass support, which serves as a master for templating, as well as on the parameters of PDMS fabrication such as the ratio of the curing agent and elastomer, use of vacuum, curing time and temperature. The results indicate that higher ratios of curing agent and elastomer, longer curing time and lower temperature are the most favorable conditions to obtain negative diatom replicas of good quality with features of 50 nm. Although this method can give very precise results producing high-resolution molds with all micro- and nanostructures replicated, we revealed some limitations regarding the size and morphology of the species used. These results indicate that large round and flat diatom species seem to be more suitable for the cast molding.

  20. Optimization of the replica molding process of PDMS using pennate diatoms

    International Nuclear Information System (INIS)

    Biomimetic fabrication of nanostructured materials has recently attracted the attention of researchers as a cost-effective and easily applicable method of nanotexturing. Different techniques and materials have been used in order to replicate natural patterns, among which polydimethylsiloxane (PDMS Sylgard 184®) was recently used to replicate the micro- and nanoscale patterns from centric diatoms. In this paper, we test the reproducibility and precision of this approach using various morphologically different diatom species trying to optimize the molding parameters. The optimization process is focused on immobilization of diatoms on the glass support, which serves as a master for templating, as well as on the parameters of PDMS fabrication such as the ratio of the curing agent and elastomer, use of vacuum, curing time and temperature. The results indicate that higher ratios of curing agent and elastomer, longer curing time and lower temperature are the most favorable conditions to obtain negative diatom replicas of good quality with features of 50 nm. Although this method can give very precise results producing high-resolution molds with all micro- and nanostructures replicated, we revealed some limitations regarding the size and morphology of the species used. These results indicate that large round and flat diatom species seem to be more suitable for the cast molding. (paper)

  1. Injection molding WPC

    OpenAIRE

    S:t Clair Renard, Carl

    2011-01-01

    The use of wood-plastic composites, WPC, in commercial products is today limited. Current WPC products on the market are to a large extent limited to extruded products. There are strong reasons to increase the use of WPC. WPC can be manufactured from used plastic that otherwise cannot be recycled. This paper gives a brief description of the manufacturing of WPC, including wood filler treatment, the role of coupling agents and compounding. It describes the machinery used for producing WPC, and...

  2. Effects of self-blood on the molding process of polymethyl methacrylate bone cement

    OpenAIRE

    Guo Yingjun; Nie Lin; Zhang Wen; Mu Qing

    2014-01-01

    【Abstract】Objective:To evaluate whether the self-blood has influence on the molding process of polymethyl methacrylate (PMMA) bone cement, and to make sure whether it is valuable for the clinical practice. Methods:An in vitro study was performed to evaluate the prolonging-effect of self-blood on PMMA bone cement. The effect of prolonging was evaluated by the dough time (TD) and operable time (TO). Moreover, hardness test, squeezing value test and peak temperature test were also...

  3. The fabrication and processing of 3-D woven composites using resin transfer molding

    Science.gov (United States)

    Lamattina, Bruce; Parvizi-Majidi, Azar

    Angle-interlock weaving and resin transfer molding (RTM) are used to produce fabric Carbon/Epoxy composites. Three-dimensional weave geometries allow for the interlocking of multiple layers of yarn with through-the-thickness yarns. These composites exhibit increased impact and delamination resistance over traditional two-dimensional fabric composites. The weave parameters that affect preform geometry or fiber architecture are discussed. Microstructural changes of the preform and the composite are monitored during the preform preparation and consolidation stages. Various weave geometries are produced with part thicknesses up to 4.76 mm. RTM tool design and process parameters such as pressure, temperature, and viscosity are presented.

  4. Compaction Behavior and Part Thickness Variation in Vacuum Infusion Molding Process

    Science.gov (United States)

    Yang, Jinshui; Xiao, Jiayu; Zeng, Jingcheng; Jiang, Dazhi; Peng, Chaoyi

    2012-06-01

    In vacuum infusion molding process (VIMP), it is difficult to manufacture a composite part with small dimensional tolerance, since the upper mold for the process is flexible. In this study, the static and cyclic compaction responses of five kinds of fabrics were experimentally studied under real VIMP conditions, with the effects of compaction pressure, compaction time, compaction cycle and number of the fabric layers. The static and cyclic compaction responses of the all fabrics follow different power law models and the resulting fiber volume fraction and relaxation factor increase with the number of layers. Although the resulting fiber volume fraction increases with the layer numbers, change of the fiber volume fraction of the composite parts with 10 layers to 100 layers of the all fabrics is less than 2.5%. The thickness of the composite part was monitored and measured using micrometer gauges, and the effects of processing parameters on the final thickness of part was investigated. The part thickness varies as a function of spatial coordinates and time during pre-filling, filling and post-filling stages in VIMP. The variation and the final value of the part thickness would be significantly affected by the processing parameters. Statistical results show that the final part thickness is equivalent to the thickness of the dry preform under the 0.08 MPa vacuum compaction pressure in VIMP. The difference between the fiber volume fraction of the final part and that of the dry preform is 2% ~ 5.7%.

  5. Observation of the Mold-Filling Process of a Large Hydro-Turbine Guide Vane Casting

    Science.gov (United States)

    Kang, Jinwu; Long, Haimin; Li, Yongjie; You, Rui; Hao, Xiaokun; Nie, Gang; Wang, Tianjiao; Zhang, Chengchun

    2015-02-01

    The mold-filling process has a determining effect on the quality of castings, and it has always been a hot but difficult research topic. The authors developed a wireless monitoring system for the mold-filling process of castings based on a contact time method and an observation system based on heat-resistant high-speed cameras. By using these two systems, the filling process of a turbine guide vane casting with a stepped gating system was investigated. The filling profile of the casting was recorded, and the filling time of nine typical positions was acquired. These results show that at the beginning, the liquid steel flowed out from the top ingate, which was designed to be the last to fill. The numerical simulation of the filling of the guide vane was performed, and the outflow from the top ingate were predicted. Finally, the gating system of the casting was improved with enlarged sprue. The new design features bigger sprue to ingate ratio; therefore, it could avoid the overflow from the top ingate and realize stable filling.

  6. Implications of diamond-turned versus diamond-ground mold fabrication techniques on precision-molded optics

    Science.gov (United States)

    Mertus, Lou; Symmons, Alan

    2012-10-01

    In recent years, the trend within the molded optics community has been an overall advancement in the capability to diamond grind molds using a variety of grinding techniques. Improvements in grinding equipment, materials and tooling have enabled higher quality ceramic and carbide molds and thereby lenses. Diamond turned molds from ductile metals are still used prevalently throughout the molding industry. Each technology presents a unique set of advantages and disadvantages whether used for precision injection molding of plastic optics or precision glass molding. This paper reviews the manufacturing techniques for each approach and applicable molding process. The advantages and disadvantages of each are compared and analyzed. The subtle differences that exist in optics molded from each technique and the impact they have on the performance in various applications is reviewed. Differences stemming from tooling material properties, material-specific minor defects, as well as cutting and grinding process-induced artifacts are described in detail as well as their influence on the roughness, waviness, and form errors present on the molded surface. A comparison with results between similar surfaces for both diamond grinding and diamond turning is presented.

  7. Energy-Saving Effect of the Add-on Energy Recovery System for Electric Motor Drive Systems in the Injection Molding Machine

    Science.gov (United States)

    Takahashi, Keisuke; Hiraki, Eiji; Tanaka, Toshihiko

    The regenerative energy from the motor drive systems used in the injection molding is consumed by resistors connected to the DC bus of the inverters. Recently the recovery systems of the regenerative energy with a bi-directional DC-DC converter and capacitors have been developed. In this paper a new control strategy of the EDLC based energy recovery system is proposed. The basic principle of the proposed control strategy and the power losses consumed in the energy recovery system are discussed in detail. The validity and practicability are confirmed by digital computer simulation.

  8. Integrally cored ceramic investment casting mold fabricated by ceramic stereolithography

    Science.gov (United States)

    Bae, Chang-Jun

    Superalloy airfoils are produced by investment casting (IC), which uses ceramic cores and wax patterns with ceramic shell molds. Hollow cored superalloy airfoils in a gas turbine engine are an example of complex IC parts. The complex internal hollow cavities of the airfoil are designed to conduct cooling air through one or more passageways. These complex internal passageways have been fabricated by a lost wax process requiring several processing steps; core preparation, injection molding for wax pattern, and dipping process for ceramic shell molds. Several steps generate problems such as high cost and decreased accuracy of the ceramic mold. For example, costly tooling and production delay are required to produce mold dies for complex cores and wax patterns used in injection molding, resulting in a big obstacle for prototypes and smaller production runs. Rather than using separate cores, patterns, and shell molds, it would be advantageous to directly produce a mold that has the casting cavity and the ceramic core by one process. Ceramic stereolithography (CerSLA) can be used to directly fabricate the integrally cored ceramic casting mold (ICCM). CerSLA builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This dissertation addresses the integrally cored casting ceramic mold (ICCM), the ceramic core with a ceramic mold shell in a single patternless construction, fabricated by ceramic stereolithography (CerSLA). CerSLA is considered as an alternative method to replace lost wax processes, for small production runs or designs too complex for conventional cores and patterns. The main topic is the development of methods to successfully fabricate an ICCM by CerSLA from refractory silica, as well as related issues. The related issues are the segregation of coarse fused silica powders in a layer, the degree of segregation parameter to prevent segregation, and sintering and cristobalite transformation in fused silica compacts.

  9. An Empirical Model for Resin Viscosity During Cure in Vacuum Infusion Molding Process

    Science.gov (United States)

    Yang, Jinshui; Xiao, Jiayu; Zeng, Jingcheng; Peng, Chaoyi; Feng, Xuebin; Hou, Binbin

    2012-06-01

    The rheological behaviors of a low viscosity epoxy resin system (RIMR135/RIMH137) for vacuum infusion molding process (VIMP) were studied with viscosity experiments. And an empirical model has been developed to predict the viscosity of the resin system during curing at low extents of cure, which is of significance during the mould filling stage in VIMP. Good agreement is observed between the experimental data and the model predicted viscosity. The processing windows of the resin system for VIMP can be predicted by the proposed models. The results show that the optimum processing temperature range of RIMR135/RIMH137 epoxy resin system for VIMP is from 25°C to 45°C, at which the resin system can maintain the viscosity less than 500 mPa·s for 75 min at least.

  10. Internal stresses analysis in telectroformed nickel shells for thermoplastics injection mold core (rapid tooling); Analisis de las tensiones internas en las cascaras de niquel electroconformadas que se utilizan como inserto de un molde de inyeccion de termoplasticos (rapid tooling)

    Energy Technology Data Exchange (ETDEWEB)

    Monzon, M. D.; Marrero, M. D.; Benitez, A. N.; Hernandez, P. M.

    2005-07-01

    This study deals with a research field started at the LFI (Laboratorio de Fabricacion Integrada) of the ULPGC (Universidad de Las Palmas de Gran Canaria). Its aim is to analyse and propose improvements in the electroformed nickel cores manufacture. The main application of these cores is to be used as plastic injection molds. It has been considered an important part of this study taking under consideration internal stresses that appear in the nickel electroformed core. These stresses play a determinant role towards reaching a dimensional and resistant quality standard of the shells, which will be later transformed into cores. The investigation includes not only a theoretic study but also an experimental one. the testing method has the remarkable advantage of a wide industrial application because of its simplicity, low cost and reproducibility of the electrolytic bath actual conditions. (Author) 7 refs.

  11. Molding mineral within microporous hydrogels by a polymer-induced liquid-precursor (PILP) process.

    Science.gov (United States)

    Cheng, Xingguo; Gower, Laurie B

    2006-01-01

    Natural biominerals often have exquisite morphologies, where the cells exercise a high degree of crystallographic control through secretion of biological macromolecules and regulation of ion transport. One important example is the sea urchin spine. It has recently been shown to be formed through deposition of a transient amorphous calcium carbonate (ACC) precursor phase that later transforms to single-crystalline calcite, ultimately forming an elaborate three-dimensional microporous calcium carbonate structure with interconnected pores. Macromolecules associated with the mineral phase are thought to play a key role in regulating this transformation. The work described here mimics this type of morphological control by "molding" an amorphous calcium carbonate precursor within a porous poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel that has been prepared as a negative replica from the void space of an urchin spine. Using an acidic biomimetic polymer as a process-directing agent, we show that polyaspartic acid induces amorphous calcium carbonate (ACC) nanoparticles, which have fluidic character and therefore are able to infiltrate the PHEMA hydrogel replica and coalesce into the convoluted morphology that replicates the original microporous structure of the sea urchin spine. By "molding" calcium carbonate into a complex morphology at room temperature, using a precursor process that is induced by a biomimetic acidic macromolecule, the PILP process is a useful in vitro model for examining different aspects of the amorphous-to-crystalline transformation process that is apparently used by a variety of biomineralizing organisms. For example, although we were able to replicate the overall morphology of the spine, it had polycrystalline texture; further studies with this system will focus on controlling the nucleation event, which may help to elucidate how such a convoluted structure can be prepared with single-crystalline texture via an amorphous precursor. Through a better understanding of the mechanisms used by organisms to regulate crystal properties, such biomimetic processes can lead to the synthesis of materials with superior electronic, mechanical, and optical properties. PMID:16454504

  12. Moldagem por injeção em baixa pressão de peças complexas de cerâmicas avançadas produzidas com pós submicrométricos / Low-pressure injection molding of complex parts of advanced ceramic produced with fine powder

    Scientific Electronic Library Online (English)

    J. E., Zorzi; C. A., Perottoni; J. A. H. da, Jornada.

    2004-09-01

    Full Text Available A moldagem por injeção em baixa pressão (MIBP) tem constituído, nos últimos anos, uma excelente alternativa para a produção de pequenos lotes de peças cerâmicas diversificadas e com formas complexas. Esta técnica de conformação é relativamente simples e barata, mas apresenta diversos problemas na et [...] apa de extração dos ligantes, principalmente quando o pó cerâmico é muito fino e as peças possuem grande seção transversal. Neste trabalho é descrita uma metodologia específica para a produção de peças cerâmicas por moldagem por injeção a baixa pressão de alumina submicrométrica (0,4 mim), incluindo a formulação da mistura para injeção, bem como detalhes do processo de extração dos ligantes orgânicos utilizados na moldagem. Para o desenvolvimento deste processo fez-se necessário (i) entender melhor o processo de MIBP, (ii) desenvolver a formulação da mistura de pó cerâmico e aditivos orgânicos, (iii) confeccionar moldes adequados para a injeção a baixas pressões e (iv) otimizar os parâmetros de injeção. A metodologia desenvolvida neste trabalho, possibilita a confecção de peças cerâmicas complexas, com seção transversal relativamente grande, permitindo uma produção robusta de pequenos lotes de peças cerâmicas diversificadas com ótima qualidade e excelente reprodutibilidade. Abstract in english In the past years, low-pressure injection molding (LPIM) has been a good alternative for the production of small batches of diversified complex shapes ceramic parts. This molding technique is relatively simple and cheap, but presents several problems related to debinding, especially for fine ceramic [...] particle, and large cross-section ceramic pieces. In this work, we present a metodology for the production of ceramic parts based on the LPIM of submicrometer-sized alumina powder (0.4 mum). The binder formulation is described, as well as the details of the debinding stage. For the development of this process it was necessary (i) to achieve a better understanding of the LPIM process, (ii) develop the binder formulation and to find the better proportion for the binder plus ceramic powder mixture, (iii) to prepare molds suitable for LPIM and (iv) to optimize the injection parameters. The procedure here reported makes it possible to produce complex shape ceramic parts, with relatively large cross-section, allowing the robust production of small batches of diversified ceramic parts, with high quality and excellent reproducibility.

  13. Method for molding ceramic powders using a water-based gel casting process

    Science.gov (United States)

    Jenny, Mark A. (Knoxville, TN); Omalete, Ogbemi O. (Lagos, NG)

    1992-09-08

    A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant, and a monomer solution. The monomer solution includes at least one monofunctional monomer and at least one difunctional monomer, a free-radical initiator, and a aqueous solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, whereafter the product may be sintered.

  14. Resin Flow Behavior Simulation of Grooved Foam Sandwich Composites with the Vacuum Assisted Resin Infusion (VARI Molding Process

    Directory of Open Access Journals (Sweden)

    Yibo Wu

    2012-07-01

    Full Text Available The resin flow behavior in the vacuum assisted resin infusion molding process (VARI of foam sandwich composites was studied by both visualization flow experiments and computer simulation. Both experimental and simulation results show that: the distribution medium (DM leads to a shorter molding filling time in grooved foam sandwich composites via the VARI process, and the mold filling time is linearly reduced with the increase of the ratio of DM/Preform. Patterns of the resin sources have a significant influence on the resin filling time. The filling time of center source is shorter than that of edge pattern. Point pattern results in longer filling time than of linear source. Short edge/center patterns need a longer time to fill the mould compared with Long edge/center sources.

  15. A study of interfacial heat transfer and process parameters in squeeze casting and low pressure permanent mold casting

    Science.gov (United States)

    Krishna, Prasad

    2001-08-01

    With the emerging demand for energy efficient and environment-friendly automobiles, cast aluminum alloys are increasingly being used in their manufacture. In this context, two permanent mold casting processes, namely, Squeeze Cast Permanent Mold and Low Pressure Permanent Mold (LPPM) have become very popular in the production of high integrity shape-cast aluminum components. However, many industries are yet to benefit from the full potential of these processes due to limited understanding of the effect of process parameters on casting quality and the necessary boundary conditions for computer modeling and simulation so as to minimize costly field trials. This dissertation attempts to address some of these concerns facing today's foundry industry. An experimental investigation of the Indirect Squeeze Casting Process was conducted by pouring molten Al-7Si-0.3Mg (A356) alloy into a specially designed and instrumented mold, mounted on a horizontal clamped-vertical shot squeeze caster (HVSC). Temperature measurements close to the metal/mold interface were made and compared with the results of the numerical simulation of heat flow during solidification and cooling of castings. The Heat Transfer Coefficient (HTC), a critical parameter essential for any solidification simulation, was estimated based on the simulation that gave the best fit to the experimental temperature data. During the solidification process, the HTC is relatively uniform over the entire casting and on reaching a critical solidification pressure, the HTC is close to 4500 W/m2 K. The work has also provided a correlation of Secondary Dendrite Arm Spacing (SDAS) with cooling rate for a modified A356 alloy. Low Pressure Permanent Mold Casting experiments were conducted by pouring a nearly identical aluminum alloy into an instrumented, coated mold mounted on a low pressure casting machine. The pressure levels, along with the time required to achieve complete filling, were microprocessor controlled in the casting machine. The HTC evaluation and SDAS-Cooling Rate Correlation were made in a similar manner to the Squeeze Casting study. A novel approach to estimating the HTC, accounting for the temporal and spatial temperature and thermal property variations, is presented. The maximum and minimum values of the HTC in this case were close to 2000 W/m2 K with no air gap and 400 W/m2 K with an air gap formation. The influences of air gap formation and mold coatings in controlling interfacial heat transfer were also modeled. It is expected that the HTCs and SDAS-Cooling Rate Correlations for the two casting processes will assist foundry engineers in deriving maximum benefits from each process.

  16. Void Prediction During Liquid Composite Molding Processes: Wetting and Capillary Phenomena

    CERN Document Server

    Abdelwahed, Mohamed Amine Ben; Bizet, Laurent; Bréard, Joël

    2012-01-01

    The aim of this work is to contribute in improving fibrous preforms impregnation for Liquid Composite Molding (LCM) processes. The void prediction in LCM sparks off interest within the Composite Material elaboration because it represents a significant issue to keep the expected mechanical properties of the final product. The liquid properties, the preform geometry and the flow conditions impact the void or bubble entrapped inside and outside the yarns. Nevertheless, due to the complex geometry of the reinforcement, experimental characterization of bubble formation remains delicate. Thus, our study deals with two simple model networks representing connected pores so called "Pore Doublet Model". A first is considering two capillaries converging on a node (T-junction) and a second is representing two capillaries interconnected with a supplying principle. In this paper, we emphasize on microfluidic and millifluidic approaches where wetting and capillary forces are significant during bubble formation mechanism.

  17. Heat-radiation combination for control of mold infection in harvested fruits and processed cereal foods

    International Nuclear Information System (INIS)

    A combination of mild heat and low dose irradiation was found to extend the shelf-life of fresh fruits and processed cereal foods by controlling mold infection. Chapaties (Indian unleavened bread) and bread slices packed in polycell pouches, subjected to 50 krad followed by dry heat (650C) were free from mold and shelf-stable for 10 weeks at ambient temperature (28-320C). Inoculated pack studies confirmed the efficiency of the treatment. No immediate changes in organoleptic attributes were discernible even after exposure to 100 krad. The quality deterioration in sliced bread stored for 2 1/2 months has been attributed to natural staling rather than radiation. Hot water dip (500C for 5 min) followed by 150 krad irradiation extended the shelf-life of fresh figs by 3-4 days at 28-320C and 8-10 days at 150C. Regardless of the sequence of treatments, combination of heat and 100 krad extended the shelf-life of grapes both at ambinet and refrigerated storage. In mangoes, heat followed by 50 krad was effective in controlling anthracnose and stem-end rot whereas in bananas irradiated for delayed ripening, hot water treatment can be used as a supplementary process to control stem-end rot. Quality of combination treated fruits was comparable to normally ripened fruits. In vitro studies with fungal pathogens isolated from the above fruits and cereal foods revealed that the synergistic effect of heat-radiation combination depends on the sequence of treatments which varied with respect to different pathogens studied. Some biochemical aspects of combination treated fruits is discussed. (F.J.)

  18. Efecto del proceso de transformación sobre el coeficiente de endurecimiento por deformación en polímeros / Effect of the molding process on the strain hardening index by deformation in polymers

    Scientific Electronic Library Online (English)

    Rosa, Morales; María, Candal; Jennifer, Robles.

    2009-12-01

    Full Text Available El objetivo principal de este trabajo fue analizar el comportamiento del coeficiente de endurecimiento por deformación (Gp) en materiales plásticos, para diferentes condiciones de inyección y velocidades de deformación durante el ensayo mecánico. Se inyectaron probetas tipo I de Polietileno de Alta [...] Densidad (PEAD 2811) modificando las variables del proceso de inyección (presión, velocidad y temperatura de inyección). Se evaluaron las propiedades tensiles y se determinaron los parámetros mecánicos (Módulo de Young, Esfuerzo y Deformación a la fluencia y Gp). Se encontró que el Gp disminuye con la presión de inyección y se mantiene constante al incrementar la temperatura de inyección, sin embargo, con la velocidad de inyección presenta una dualidad de comportamientos, es decir a bajas velocidades de ensayo aumenta, mientras que a altas velocidades disminuye el coeficiente. También se obtuvo que a medida que la velocidad de deformación aumenta el Gp disminuye Abstract in english The main objective of this study was to analyze the behavior of the strain hardening coefficient (Gp) in plastic materials, for different injection molding conditions and the strain rate during a mechanical test. Test specimen type I of High Density Polyethylene (HDPE 2811) was injected under differ [...] ent process conditions (injection pressure, injection temperature and injection velocity). The tensile properties were evaluated and the mechanical parameters (Young modulus, yield stress, yield strain and Gp) were determined. Gp decreases with injection pressure, and remains constant by increasing injection temperature; however, with injection velocity, it presents a mixed behaviour. A low velocity generated an increase of the Gp and a high velocity decreases the Gp. Also, the Gp decreases with an increase in the strain rate

  19. Thermal particle injection into the shock acceleration process

    International Nuclear Information System (INIS)

    Theoretical models of thermal-particle injection into the process of charged-particle acceleration by MHD shock waves passing through astrophysical plasmas are reviewed. Consideration is given to the initial plasma and shock parameters determining the number of injected particles, the possibility of achieving the saturated injection regime, and the feasibility of nonsaturated injection. Selected laboratory data are presented for comparison and the need for further development of injection theory within the framework of collisionless-shock physics, for a model of electron injection, and for experiments involving different shock-formation conditions is indicated. 24 references

  20. Processamento de placa espessa de compósito através de moldagem por transferência de resina / Processing of thick composite plate by resin transfer molding process

    Scientific Electronic Library Online (English)

    Wanderley F. de, Amorim Júnior; Gustavo Queiroz, Chaves; Verônica M. A., Calado; Fernando Luiz, Bastian.

    2006-09-01

    Full Text Available Devido às suas elevadas propriedades mecânicas específicas, os materiais compósitos estão enfrentando demandas novas, onde a capacidade de produção em massa a um custo mais acessível se tornou indispensável. A Moldagem por Transferência de Resina ou RTM (Resin Transfer Molding) constitui um promisso [...] r processo de fabricação de materiais compósitos. O objetivo deste trabalho é o estudo experimental do processo de infusão durante a fabricação de placa espessa por RTM. Os materiais usados nos experimentos foram: tecido de fibra de vidro e resina éster-vinílica com catalisador Butanox e acelerador CoNaP. As placas de material compósito eram constituídas de 32 camadas de fibra de vidro com espessura de 25,4 mm. Dois tipos de experimentos foram realizados: o primeiro para medir a influência do sistema de injeção de resina no processamento e o segundo para medir a influência da quantidade de resina presente no reservatório de injeção. Nos processamentos realizados, o sistema de injeção de resina alterou o tempo de preenchimento da preforma. A variação na quantidade de resina no reservatório não só alterou os tempos de preenchimento como impediu o preenchimento da preforma em um dos processamentos realizados. Não foi possível impedir o fenômeno de race-tracking. Baseando-se nos experimentos realizados, pode-se concluir que: o sistema de injeção de resina é importante no real entendimento do processamento por RTM e que a quantidade de resina no reservatório de injeção pode influenciar o processamento por RTM. Abstract in english Because of their high specific mechanical properties, composite materials are facing new demands, where the large scale production capacity with low cost became important. Resin Transfer Molding (RTM) constitutes a promising process of composite materials manufacturing. The objective of this work is [...] an experimental study of the infusion process during the manufacture of thick plate by RTM.The materials used in the experiments were: fiber glass fabric and vinylester resin with Butanox initiator and CoNaP accelerator. The preform had 32 layers of fiber glass reinforcements whose dimension was approximately 25,4 mm thick. Two types of experiments were carried out: the first one, to measure the influence of the resin injection system on the processing and the second one, to measure the influence of the amount of resin in the reservoir on the injection processing. By the experiments, we could conclude that the resin injection system and the variation of the amount of resin modified the fulfilling time of the preform and prevented the fulfilling of the preform in the experiments. It was not possible to prevent the phenomenon of race-tracking. The resin injection system and the variation of the amount of resin in the reservoir of injection influence RTM processes.

  1. New processing route for ZrSiO4 by powder injection moulding using an eco-friendly binder system

    International Nuclear Information System (INIS)

    New processing route has been developed for zircon based on powder injection moulding (PIM). Raw zircon powders, obtained from mineral sands, have been processed using a new water soluble binder system composed of PEG and CAB. Water solvent debinding stage has been studied in depth. On one hand, influence of some debinding parameters (temperature, debinding rate, additives and the use of climate chamber) has been tested. On the other hand, new binder systems were tested and compared with previous studied ones. The full PIM process has been carried out. Mixing, injection molding, solvent and thermal debinding and finally sintering, have been performed with the optimal binder system composition. Homogeneity along the process has been assessed by thermo-gravimetric analysis and by density measurements. After sintering, dimensional variation, density and fracture surface obtained after flexural strength test, have been analyzed. A competitive flexural strength has been achieved for injected zircon samples. (Author)

  2. Os efeitos no empacotamento de peças injetadas para diferentes espessuras de canais de ataque (gate) tipo filme / The effects of injection molding packing for different thickness of film type gates

    Scientific Electronic Library Online (English)

    Altair Carlos da, Cruz; Ricardo Pedro, Bom.

    Full Text Available Este trabalho tem como objetivo determinar a variação da massa de corpos de prova fabricados pelo processo de moldagem por injeção. A partir de equações que tratam da solidificação de placas, foi correlacionado o tempo de solidificação do canal de ataque com o tempo de início de estabilização da mas [...] sa do corpo de prova obtido na cavidade do molde de injeção. Para o desenvolvimento experimental foi utilizado o copolímero estireno-acrilonitrila (SAN). Para a realização dos corpos de prova, foi necessário secar o material, fixar alguns parâmetros de processo, tais como pressão de injeção, tempo de injeção, temperatura nos diferentes estágios e temperatura do molde. Os parâmetros variáveis foram o tempo e a pressão de recalque. Com os corpos de prova prontos, suas massas foram determinadas, inicialmente, para o conjunto corpo de prova e canais de distribuição; em seguida, para o corpo de prova individualmente, sendo este previamente separado dos canais de distribuição. A variação da massa dos corpos de prova para as diferentes pressões de recalque e seus respectivos desvios-padrão foram representadas graficamente em função da variação do tempo de recalque. A massa do corpo de prova começou a estabilizar a partir de um certo tempo. Este tempo foi determinado graficamente e ficou coerente com os resultados dos tempos calculados a partir de equações que tratam do resfriamento de placas. Abstract in english The aim of his study is to determine the model test bulk used by the injection molding process. The mathematical model governing by the plate solidification will indicate the solidification time of the gate together with the beginning of the stabilization of the cavity bulk. In this test a styrene-a [...] crylonitrile copolymer (SAN) will be used. In order to develop the model tests, the material had to be dried to establish some parameters like: injection pressure, injection time, temperature of the different stages as well as moulding temperature. The variable parameters were the time and the discharge pressure. As the model tests were fully develoved, bulks were determined, first for the mould cavity and branches and next for the single cavity which was separated from the branches. The variation of the cavity bulk for the different discharge pressures and the standard deviation were graphically represented due to the time deviation of the discharge. The results showed that the time the bulk cavity begins to stabilize matches the calculated time, for the non-flow temperature, as well as the glass part temperature, the discharge pressure.

  3. Process for the production of prismatic graphite molded articles for high temperature fuel elements

    International Nuclear Information System (INIS)

    Prismatic graphite molded objects for high temperature fuel elements are prepared by producing the outer geometry and the holes for cooling channels and for receiving fuel and fertile materials in the formation of the carbon object

  4. Processing and Properties of Vacuum Assisted Resin Transfer Molded Phenylethynyl Terminated Imide Composites

    Science.gov (United States)

    Cano, Roberto J.; Ghose, Sayata; Watson, Kent A.; Chunchu, Prasad B.; Jensen, Brian J.; Connell, John W.

    2012-01-01

    Polyimide composites are very attractive for applications that require a high strength to weight ratio and thermal stability. Recent work at NASA Langley Research Center (LaRC) has concentrated on developing new polyimide resin systems that can be processed without the use of an autoclave for advanced aerospace applications. Due to their low melt viscosities and long melt stability, certain phenylethynyl terminated imides (PETI) can be processed into composites using high temperature vacuum assisted resin transfer molding (HT-VARTM). VARTM has shown the potential to reduce the manufacturing cost of composite structures. In the current study, two PETI resins, LARC(Trademark) PETI-330 and LARC(Trademark) PETI-9, were infused into carbon fiber preforms at 260 C and cured at temperatures up to 371 C. Photomicrographs of polished cross sections were taken and void contents, determined by acid digestion, were below 4.5%. Mechanical properties including short block compression (SBC), compression after impact (CAI), and open hole compression (OHC) were determined at room temperature, 177 C, and 288 C. Both PETI-9 and PETI-330 composites demonstrated very good retention of mechanical properties at elevated temperatures. SBC and OHC properties after aging for 1000 hours at temperatures up to 288 C were also determined.

  5. Nanopatterning planar and non-planar mold surfaces for a polymer replication

    DEFF Research Database (Denmark)

    Cech, Jiri; Pranov, Henrik

    2013-01-01

    We present a novel process to create nanopatterns on planar and non-planar polymer replication tools, such as metallic molds for an injection molding. Such tools with nanopatterned cavities then allow affordable mass production of nanopatterned polymer parts with inherent advanced functionalities such as low reflectivity or color effects, self cleaning, superhydrofobicity, antifouling, etc, all created in a single injection molding cycle. Presented process is based on the classic cleanroom microfabrication of micro/nano patterns, nickel electroplating and template removal to form a flexible, freestanding nickel foil with a reversed pattern. This foil is then used either as a direct master for polymer replication or as a master for an extremely high pressure embossing of such master onto a metallic injection mold cavity surface coated with special coating, which, when cured, forms robust and hard, glass-like material. We have demonstrated nanopattern transfer on both planar and non-planar geometries and our nanopatterned mold coating can sustain more than 10.000 injection molding cycles. We can coat our nanopatterned mold surfaces with a monolayer of perfluorosilane to further reduce surface energy and sticktion and to facilitate de-molding of plastic parts.1 This allows forming of affordable plastic parts with advanced functionality.

  6. Study on Improving Thickness Uniformity of Microfluidic Chip Mold in the Electroforming Process

    Directory of Open Access Journals (Sweden)

    Liqun Du

    2016-01-01

    Full Text Available Electroformed microfluidic chip mold faces the problem of uneven thickness, which decreases the dimensional accuracy of the mold, and increases the production cost. To fabricate a mold with uniform thickness, two methods are investigated. Firstly, experiments are carried out to study how the ultrasonic agitation affects the thickness uniformity of the mold. It is found that the thickness uniformity is maximally improved by about 30% after 2 h electroforming under 200 kHz and 500 W ultrasonic agitation. Secondly, adding a second cathode, a method suitable for long-time electroforming is studied by numerical simulation. The simulation results show that with a 4 mm width second cathode used, the thickness uniformity is improved by about 30% after 2 h of electroforming, and that with electroforming time extended, the thickness uniformity is improved more obviously. After 22 h electroforming, the thickness uniformity is increased by about 45%. Finally, by comparing two methods, the method of adding a second cathode is chosen, and a microfluidic chip mold is made with the help of a specially designed second cathode. The result shows that the thickness uniformity of the mold is increased by about 50%, which is in good agreement with the simulation results.

  7. Effects of self-blood on the molding process of polymethyl methacrylate bone cement

    Directory of Open Access Journals (Sweden)

    Guo Yingjun

    2014-07-01

    Full Text Available 【Abstract】Objective:To evaluate whether the self-blood has influence on the molding process of polymethyl methacrylate (PMMA bone cement, and to make sure whether it is valuable for the clinical practice. Methods:An in vitro study was performed to evaluate the prolonging-effect of self-blood on PMMA bone cement. The effect of prolonging was evaluated by the dough time (TD and operable time (TO. Moreover, hardness test, squeezing value test and peak temperature test were also conducted to complete the evaluation of this program. Results:The self-blood, especially the plasma, could greatly prolong the handling time of PMMA bone cement without affecting its basic characteristics including hardness, leakage level and peak temperature. On the other hand, we found that in some abnormal conditions, for example with hyperlipemia, self-blood though can also prolong the handling time, would cause some sideeffects. Conclusion: We report a new effective way to prolong the handling time of PMMA bone cement by adding moderate amount of self-blood. But "individualized medicine" should be noticed because some abnormal conditions like hyperlipemia would cause undesired side-effects. Key words: Plasma; Serum; Polymethyl methacrylate; Hyperlipidemias

  8. Hot press molding process for pyramid-type glass optical multiplexer

    Science.gov (United States)

    Ko, Myeong-Jin; Park, Soon-Sub

    2014-12-01

    By developing a pyramid-shaped reflector, we were able to remove the optical filter that causes the decline in light efficiency in existing systems. A pyramid-type glass optical multiplexer (MUX) can be designed for beam coupling efficiency >60% in a combined module. The module was designed and optimized using CODE V, which utilizes nonlinear curve fitting numerical analysis. Based on optical design data, aspheric grinding paths were developed using ULG APS software. Tungsten carbide optical MUX mold cores were fabricated with an ultraprecision grinding machining device [ULG-100C(H3)] and optimum grinding machining of optical surface roughness (type optical MUX was fabricated using the hot press molding technique, and it was measured by using a contact geometry measuring device for reflection angle and angle uniformity. The measurement data were suitable for 49±0.05 deg, which was the design criterion. In addition, angle uniformity was >99.985%. A pyramid-type glass optical MUX molding technique was developed using an optical mold design, ultraprecision grinding machining technology, and a hot press molding system.

  9. Multilevel micro-structuring of glassy carbon molds for precision glass molding

    Science.gov (United States)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans Peter; Plöger, Sven; Hermerschmidt, Andreas

    2015-09-01

    Replication techniques for diffractive optical elements (DOEs) in soft materials such as plastic injection molding are state of the art. For precision glass molding in glasses with high transition temperatures, molds with extreme thermal resistivity, low chemical reactivity and high mechanical strength are needed. Glassy Carbon can be operated up to 2000°C making it possible to mold almost all glasses including Fused Silica with a transition temperatures above 1060°C. For the structuring of Glassy Carbon wafers photolithography and a RIE process is used. We have developed a process using Si as a hard mask material. If the flow rates of the etching gases O2 and SF6 are chosen properly, high selectivity of GC to Si 19:1 can be achieved, which provides excellent conditions to realize high resolution elements with feature size down to 1 micron and fulfills requirements for optical applications. We fabricated several multilevel GC molds with 8 levels of structuring. Two different optical functionalities were implemented: 6x6 array beamsplitter and 1x4 linear beamsplitter. The molds were applied for precision glass molding of a low Tg glass L-BAL 42 (from Ohara) with a transition temperature of 565°C. Their optical performance was measured. A more detailed analysis of the impact of mold fabrication defects on optical performance is done. Rigorous coupled wave analysis simulations are performed, where we included fabrication constrains such as duty cycle, edge depth errors, wall verticality and misalignment errors. We will compare the results with the design specifications and discuss the influence of fabrication errors introduced during the different process steps.

  10. Determination of the heat transfer coefficient at the metal-sand mold interface of lost foam casting process

    Science.gov (United States)

    Zhang, Liqiang; Tan, Wenfang; Hu, Hao

    2015-07-01

    For modeling solidification process of casting accurately, a reliable heat transfer boundary condition data is required. In this paper, an inverse conduction model was established to determine the heat flux and heat transfer coefficient at the metal-sand mold interface for cylindrical casting in the lost foam process. The numerically calculated temperature was compared with analytic solution and simulation solution obtained by commercial software ProCAST to investigate the accuracy of heat conduction model. The instantaneous cast and sand mold temperatures were measured experimentally and these values were used to determine the interfacial heat transfer coefficient (IHTC). The IHTC values during lost foam casting were shown to vary from 20 to 800 W m-2 K-1. Additionally, the characteristics of the time-varying IHTC have also been discussed in this study.

  11. Simulation of the Vacuum Assisted Resin Transfer Molding (VARTM) process and the development of light-weight composite bridging

    Science.gov (United States)

    Robinson, Marc J.

    A continued desire for increased mobility in the aftermath of natural disasters, or on the battlefield, has lead to the need for improved light-weight bridging solutions. This research investigates the development of a carbon/epoxy composite bridging system to meet the needs for light-weight bridging. The research focuses on two main topics. The first topic is that of processing composite structures and the second is the design and testing of these structures. In recent years the Vacuum Assisted Resin Transfer Molding (VARTM) process has become recognized as a low-cost manufacturing alternative for large Fiber Reinforced Polymer (FRP) composite structures for civil, military, and aerospace applications. The success of the VARTM process (complete wet-out) is very sensitive to the resin injection strategy used and the proper placement of flow distribution materials and inlet and vacuum ports. Predicting the flow front pattern, the time required for infusing a part with resin, and the time required to bleed excess resin at the end of filling, is critical to ensure that the part will become completely impregnated and desired fiber volume fractions achieved prior to the resin gelling (initiation of cure). In order to eliminate costly trial and error experiments to determine the optimal infusion strategy, this research presents a simulation model which considers in-plane flow as well as flow through the thickness of the preform. In addition to resin filling, the current model is able to simulate the bleeding of resin at the end of filling to predict the required bleeding time to reach desired fiber volume fractions for the final part. In addition to processing, the second portion of the dissertation investigates the design and testing of composite bridge deck sections which also serve as short-span bridging for gaps up to 4 m in length. The research focuses on the design of a light-weight core material for bridge decking as well as proof loading of short-span bridge sections in the lab and extensive field testing using a variety of wheeled and tracked vehicles at different crossing speeds and crossing conditions.

  12. Confine Clay in an Alternating Multilayered Structure through Injection M