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1

Bubble growth in mold cavities during microcellular injection molding processes  

Energy Technology Data Exchange (ETDEWEB)

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

Moon, Yong Rak [University of Toronto, Toronto (Canada); Lee, Kyoung Soo; Cha, Sung W. [Yonsei University, Seoul (Korea, Republic of)

2009-12-15

2

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

2009-12-01

3

Process and part filling control in micro injection molding  

DEFF Research Database (Denmark)

The influence of process parameters on μ-injection molding (μIM) and on μ-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 μ-parts to evaluate filling behavior of the polymer melt flowing through μ-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 μIM process and on the μ-parts filling.

Tosello, Guido; Hansen, Hans Nørgaard

2008-01-01

4

Study on heat flux from resin to mold in injection molding process  

Energy Technology Data Exchange (ETDEWEB)

Recently, an injection molding of thermoplastic is widely used in many industries, because this manufacturing method is very suitable for mass production. For injection molding processes, a number of software packages for simulating an injection molding process have been developed. It is assumed in these software packages that the heat transfer coefficient between the resin and the mold surface is constant at the filling or cooling stages. In general, when melted resin flows into the mold, heat is generated in the flowing resin because of the high viscosity at the filling stage. Moreover at the cooling stage, a separation of the molded part from the mold surface generally occurs because of shrinkage of the molded material. Therefore, the heat transfer coefficient has not been accurately obtained yet at these stages. In this paper, the temperature near the surface of the mold cavity has been experimentally measured, so the heat flux that flows from the resin to the mold has been able to be analytically estimated by an inverse conduction method. On the other hand, the separating behavior of the resin from the mold surface has been measured using an ultrasonic transducer attached to the outer surface of the stationary mold. The heat flux that flows from the resin to the mold has been analytically estimated. The apparent heat transfer coefficient can be obtained from the heat flux and the representative temperature difference, which is measured by an ultrasonic technique. It was discovered that the heat flux and the apparent heat transfer coefficient are hardly influenced by the separation.

Nishiwaki, Nobuhiko; Hori, Sankei

1999-07-01

5

Micro injection molding: characterisation of cavity filling process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Based on reciprocating micro injection molding machine, this paper characterizes the influence of machine process parameters and its transition response from velocity control to pressure control (V-P transition) on the micro cavity filling process. The method of Design of Experiment was employed to systematically and statistically investigate the effect of machine parameters on actual cavity filling process, which was described by the defined process characteristic val...

Zhang, Nan; Chu, J. S.; Gilchrist, M. D.

2011-01-01

6

Effects of process parameters in plastic, metal, and ceramic injection molding processes  

Science.gov (United States)

Plastic injection molding has been widely used in the past and is a dominant forming approach today. As the customer demands require materials with better engineering properties that were not feasible with polymers, powder injection molding with metal and ceramic powders has received considerable attention in recent decades. To better understand the differences in the plastic injection molding, metal injection molding, and ceramic injection molding, the effects of the core process parameters on the process performances has been studied using the state-of-the-art computer-aided engineering (CAE) design tool, PIMSolver The design of experiments has been conducted using the Taguchi method to obtain the relative contributions of various process parameters onto the successful operations.

Lee, Shi W.; Ahn, Seokyoung; Whang, Chul Jin; Park, Seong Jin; Atre, Sundar V.; Kim, Jookwon; German, Randall M.

2011-09-01

7

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

Directory of Open Access Journals (Sweden)

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.

J. Tepi?

2011-10-01

8

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 qu...

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

2010-01-01

9

Improved silicon carbide for advanced heat engines. I - Process development for injection molding  

Science.gov (United States)

Alternate processing methods have been investigated as a means of improving the mechanical properties of injection-molded SiC. Various mixing processes (dry, high-sheer, and fluid) were evaluated along with the morphology and particle size of the starting beta-SiC powder. Statistically-designed experiments were used to determine significant effects and interactions of variables in the mixing, injection molding, and binder removal process steps. Improvements in mechanical strength can be correlated with the reduction in flaw size observed in the injection molded green bodies obtained with improved processing methods.

Whalen, Thomas J.; Trela, Walter

1989-01-01

10

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

Directory of Open Access Journals (Sweden)

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 Taguchis 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.

P.K. Bharti

2010-09-01

11

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

DEFF Research Database (Denmark)

A newly developed μ-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 μ-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.

Tosello, Guido Technical University of Denmark,

2010-01-01

12

Processing development of Si3N4 components by injection molding  

International Nuclear Information System (INIS)

The development of complex-shaped ceramic components by powder injection molding has been considered as a promising technique by industry. In this study silicon nitride was used as a sample material for demonstrating the possibility of fabricating ceramic components by injection molding. An optimized process for the manufacture of components by injection molding will be presented. The effects of solid content, binder type, solvent and thermal debinding and effects of firing atmosphere will be discussed. Some promising physical and mechanical properties of sintered silicon nitride will be illustrated. Some prototypes will also be demonstrated. The developed technique could be extended for fabricating engine or functional components. (author)

1997-06-04

13

Ceramic injection molding  

International Nuclear Information System (INIS)

Interest in making complex net-shape ceramic parts with good surface finishing and sharp tolerances without machining is a driving force for studying the injection molding technique. This method consists of softhening the ceramic material by means of adding some plastic and heating in order to inject the mixture under pressure into a relatively cold mold where solidification takes place. Essentially, it is the same process used in thermoplastic industry but, in the present case, the ceramic powder load ranges between 80 to 90 wt.%. This work shows results obtained from the fabrication of pieces of different ceramic materials (alumina, barium titanate ferrites, etc.) in a small scale, using equipments developed and constructed in the laboratory. (Author)

1988-11-01

14

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

Directory of Open Access Journals (Sweden)

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.

Kwangho Shin

2013-12-01

15

Validation of New Process Models for Large Injection-Molded Long-Fiber Thermoplastic Composite Structures  

Energy Technology Data Exchange (ETDEWEB)

This report describes the work conducted under the CRADA Nr. PNNL/304 between Battelle PNNL and Autodesk whose objective is to validate the new process models developed under the previous CRADA for large injection-molded LFT composite structures. To this end, the ARD-RSC and fiber length attrition models implemented in the 2013 research version of Moldflow was used to simulate the injection molding of 600-mm x 600-mm x 3-mm plaques from 40% glass/polypropylene (Dow Chemical DLGF9411.00) and 40% glass/polyamide 6,6 (DuPont Zytel 75LG40HSL BK031) materials. The injection molding was performed by Injection Technologies, Inc. at Windsor, Ontario (under a subcontract by Oak Ridge National Laboratory, ORNL) using the mold offered by the Automotive Composite Consortium (ACC). Two fill speeds under the same back pressure were used to produce plaques under slow-fill and fast-fill conditions. Also, two gating options were used to achieve the following desired flow patterns: flows in edge-gated plaques and in center-gated plaques. After molding, ORNL performed measurements of fiber orientation and length distributions for process model validations. The structure of this report is as follows. After the Introduction (Section 1), Section 2 provides a summary of the ARD-RSC and fiber length attrition models. A summary of model implementations in the latest research version of Moldflow is given in Section 3. Section 4 provides the key processing conditions and parameters for molding of the ACC plaques. The validations of the ARD-RSC and fiber length attrition models are presented and discussed in Section 5. The conclusions will be drawn in Section 6.

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

2012-02-23

16

Relationships between processing and mechanical properties of injection molded high molecular mass polyethylene + hydroxyapatite composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We apply a macromolecular-orientation approach to produce high molecular weight polyethylene (HMWPE) + hydroxyapatite (HA) ductile composites with the stiffness and strength within the range of human cortical bone. Our composites are produced with different amounts (10 to 50% by weight) of the reinforcement by two procedures: bi-axial rotating drum and twin screw extrusion (TSE). The processing is by conventional injection molding and by Scorim (shear controlled orientation in injection moldi...

Reis, R. L.; Cunha, A. M.; Oliveira, M. J.; Campos, A. R.; Bevis, M. J.

2001-01-01

17

On Optimization of Injection Molding Cooling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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, optimiz...

Ra?nnar, Lars-erik

2008-01-01

18

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2005-05-01

19

The reflectivity, wettability and scratch durability of microsurface features molded in the injection molding process using a dynamic tool tempering system  

Science.gov (United States)

In this paper the replication qualities of periodically and randomly arranged micro-features molded in the injection molding process and their effects on surface properties are studied. The features are molded in PC, PMMA and PP at different mold wall temperatures in order to point out the necessity and profitability of a variotherm mold wall temperature control system. A one-dimensional heat conduction model is proposed to predict the cycle times of the variotherm injection molding processes. With regard to these processes, the molding results are compared to the molded surface feature heights using an atomic force microscope. In addition, the effects of the molded surface features on macroscopic surfaces are characterized in terms of light reflection using a spectrometer and in terms of water wettability by measuring the static contact angle. Furthermore, due to the sensitivity of the surface features on the molded parts, their durability is compared in a scratch test with a diamond tip. This leads to successful implementation in applications in which the optical appearance, in terms of gloss and reflection, and the water repellence, in terms of drag flow and adhesion, are of importance.

Kuhn, Sascha; Burr, August; Kbler, Michael; Deckert, Matthias; Bleesen, Christoph

2011-02-01

20

Foam injection molding of thermoplastic elastomers: Blowing agents, foaming process and characterization of structural foams  

Science.gov (United States)

Polymer foams play an important role caused by the steadily increasing demand to light weight design. In case of soft polymers, like thermoplastic elastomers (TPE), the haptic feeling of the surface is affected by the inner foam structure. Foam injection molding of TPEs leads to so called structural foam, consisting of two compact skin layers and a cellular core. The properties of soft structural foams like soft-touch, elastic and plastic behavior are affected by the resulting foam structure, e.g. thickness of the compact skins and the foam core or density. This inner structure can considerably be influenced by different processing parameters and the chosen blowing agent. This paper is focused on the selection and characterization of suitable blowing agents for foam injection molding of a TPE-blend. The aim was a high density reduction and a decent inner structure. Therefore DSC and TGA measurements were performed on different blowing agents to find out which one is appropriate for the used TPE. Moreover a new analyzing method for the description of processing characteristics by temperature dependent expansion measurements was developed. After choosing suitable blowing agents structural foams were molded with different types of blowing agents and combinations and with the breathing mold technology in order to get lower densities. The foam structure was analyzed to show the influence of the different blowing agents and combinations. Finally compression tests were performed to estimate the influence of the used blowing agent and the density reduction on the compression modulus.

Ries, S.; Spoerrer, A.; Altstaedt, V.

2014-05-01

 
 
 
 
21

Studies for Polyblend Behaviour in Screw Extrusion and Injection Molding Processes  

Science.gov (United States)

Polyblend behaviour in the screw extrusion and injection molding processes was studied. Melting mechanisms for LDPE/PS polyblend were investigated, as well as a morphology development was observed. The break-up mechanism and fibrillation, as well as coalescence were clearly visible. A computer model developed for screw extrusion was applied to study material behaviour. The model is based on the flow field description in the machine.

Wilczynski, Krzysztof; Szymaniak, Zbigniew; Nastaj, Andrzej

2008-07-01

22

Progress in Titanium Metal Powder Injection Molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 im...

German, Randall M.

2013-01-01

23

A comparison of molding procedures - Contact, injection and vacuum injection  

Science.gov (United States)

The technical and economic aspects of the contact, injection and vacuum injection molding of reinforced plastic components are compared for the example of a tractor roof with a gel-coated surface. Consideration is given to the possibility of reinforcement, number of smooth faces, condition of the gel-coated surface, reliability, and labor and workplace requirements of the three processes, and advantages of molding between the mold and a countermold in smooth faces, reliability, labor requirements, working surface and industrial hygiene are pointed out. The times and labor requirements of each step in the molding cycles are examined, and material requirements and yields, investment costs, amortization and product cost prices of the processes are compared. It is concluded that, for the specific component examined, the processes of vacuum injection and injection molding appear very interesting, with injection molding processes resulting in lower cost prices than contact molding for any production volume.

Cathiard, G.

1980-06-01

24

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

2011-01-01

25

Optimization of the molding conditions for metal injection molding. Kinzoku funmatsu idashi seikei process ni okeru seikei joken no saitekika  

Energy Technology Data Exchange (ETDEWEB)

The effects of molding conditions such as injection temperature and rate on the moldability of compounds and mechanical properties of sintered compacts were studied by flow test and tensile test. The compound composed of carbonyl iron powders with an average diameter of 4.4 [mu]m and two different types of wax-polymer binders. The compound with APP (atactic polypropylene) binder gave a good moldability because of its less rapid fluidity change due to temperature as compared with that with IPP (isotactic PP) binder. As the compound was injected at lower temperatures and rates under a high-viscosity condition, the flowmark type of defect easily occurred due to solidification just after injection, while as the compound was injected at higher temperatures and rates under a low-viscosity condition, segregation of the binder occurred in the green compacts, degrading mechanical properties of the sintered compacts in both cases. The combination process of thermal and solvent debinding was featured by both short debinding time and prevention from distortion. 3 refs., 7 figs., 2 tabs.

Miura, H.; Baba, T.; Ando, S.; Honda, T. (Kumamoto University, Kumamoto (Japan). Faculty of Engineering)

1994-03-13

26

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Megat-yusoff, P. S. M.; Abdul Latif, M. R.; Ramli, M. S.

2011-01-01

27

Development of a Plastic Injection Molding Processing Laboratory for Freshman Mechanical Engineering Technology Students  

Science.gov (United States)

As is the case with many educational institutions that offer a MET degree, an introductory course in manufacturing materials and processes is required. At Penn State Erie, The Behrend College, we offer first-year Mechanical Engineering Technology (MET) students the introductory manufacturing materials and processes course. The course has both a lecture and laboratory segment. During the lab segment of the course, students have the opportunity to experience: material testing, plant tours, manufacturing processes, statistical process control, and inspection/measurement techniques. With 10 PIM machines, 3 extrusion lines, 2 thermoforming machines, and 2 blow molding machines, Penn State Behrend has the largest educational plastic injection molding (PIM) laboratory in the country. Collaborative efforts were initiated between the Mechanical Engineering Technology and Plastics Engineering Technology departments to enhance the learning experience. Resulting from the collaboration a decision was made to add a PIM laboratory to emphasize the lecture on plastic materials and processes. The PIM laboratory was developed to give the student an introduction to the PIM process, machine, mold and the effects of processing variables on the parts. Also, students would gain knowledge regarding the effects of part design on the process. Prior to the implementation of this lab, the students went on plant tours or were shown videos of the PIM process.

Meckley, Jonathan A.; Nitterright, Fredrick A.

2009-07-27

28

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

Science.gov (United States)

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.

Nguyen Thi, T. B.; Yokoyama, A.; Ota, K.; Kodama, K.; Yamashita, K.; Isogai, Y.; Furuichi, K.; Nonomura, C.

2014-05-01

29

Relationship between processing and mechanical properties of injection molded high molecular mass polyethylene + hydroxyapatite composites  

Energy Technology Data Exchange (ETDEWEB)

We apply a macromolecular-orientation approach to produce high molecular weight polyethylene (HMWPE) + hydroxyapatite (HA) ductile composites with the stiffness and strength within the range of human cortical bone. Our composites are produced with different amounts (10 to 50% by weight) of the reinforcement by two procedures: bi-axial rotating drum and twin screw extrusion (TSE). The processing is by conventional injection molding and by Scorim (shear controlled orientation in injection molding) under a wide range of processing windows. Tensile testing is performed and the corresponding performance related to the morphology evaluated by polarized light microscopy and scanning electron microscopy. The control of the processing parameters led to significant improvements of the tensile properties. Compounding by TSE and then processing by Scorim produces the maximum modulus of 7.4 GPa and the ductility as high as 19%, for the HA weight fraction of 30%. These mechanical properties match those of bone, and were obtained with much smaller amounts of HA reinforcement then has been previously reported in literature. Our PE + HA composites present the additional benefit of being ductile even for 50% HA amounts. The use Scorim is a unique way of inducing anisotropy to thick sections and to produce very stiff composites that may be used in biomedical applications with important mechanical loads. This fact, combined with the bioactive behavior of the HA phase, makes our composite usable for orthopedic load-bearing implants. (orig.)

Reis, R.L.; Cunha, A.M.; Oliveira, M.J.; Campos, A.R. [Dept. of Polymer Engineering, University of Minho, Guimaraes (Portugal); Bevis, M.J. [Wolfson Center for Materials Processing, Brunel Univ., Uxbridge (United Kingdom)

2001-04-01

30

Mechanical Properties of Sintered Martensitic Stainless Steel Fabricated by Metal Injection Molding Process  

Science.gov (United States)

The effects of sintering and heat treatment conditions on the mechanical properties of martensitic stainless steel fabricated by metal injection molding (MIM) process were investigated. The specimens were made by injecting the mixture of gas-atomized powders of 5 m and 10 m in mean particle diameter and a polymer binder into a metallic mold. The injection molded compacts were debound in air at various temperatures between 533 K and 593 K for 7.2 ks. They were sintered in vacuum at various temperatures between 1273 K and 1623 K for 7.2 ks. And the specimens were tempered at various temperatures between 373 K and 973 K after vacuum hardening. The density of the as-sintered compact of 5 m powder was higher than that of the as-sintered compact of 10 m powder. In case of the as-sintered compact of 5 m powder, the tensile strength depended on the change in density, and the tensile strength of the compact sintered at 1373 K was 1600 MPa. On the other hand, in the case of the as-sintered compact of 10 m powder, the tensile strength was rather lower than that of the as-sintered compact of 5 m powder because of coarsening of the grain size. The tensile strength and elongation of the heat-treated compact of 5 m powder were 1800 MPa and 12 %, respectively. The tensile strength and elongation of the heat-treated compact of 10 m powder were 1680 MPa and 10 %, respectively. Thus, the mechanical properties of the compacts were approximately equal to those of the wrought material.

Nakayama, Hideki; Kyogoku, Hideki

31

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)

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 210C. The highest tensile strength of the composites was achieved at 70 bar holding pressure and 150C injection temperature. However, the highest fracture strength was achieved at 80 bars whilst maintaining the injection temperature at 150C. 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

M.S. Ramli

2011-01-01

32

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

DEFF Research Database (Denmark)

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.

Gava, Alberto; Tosello, Guido

2009-01-01

33

Functional nanostructures on injection molded plastic  

DEFF Research Database (Denmark)

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.

Johansson, Alicia Charlotte; Søgaard, Emil

34

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

DEFF Research Database (Denmark)

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.

?stergaard, Peter Friis; Matteucci, Marco

2012-01-01

35

Surface microstructure replication in injection molding  

DEFF Research Database (Denmark)

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

Hansen, Hans Nørgaard

2006-01-01

36

Characterization of Injection Molded Structures  

DEFF Research Database (Denmark)

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.

Sun, Ling; Søgaard, Emil

37

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2013-12-18

38

Simulation and Design of a plastic injection mold  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Injection molding is one of the most important processes in the plastic manufacturing industry. More than one-third of all plastic materials are injection molded, And the mold is one of the main components in the injection molding process. The aim of this engineering thesis is to show detailed steps on how to design a complete mold and using the simulation software to analyze the material flow and defects in the product. The product design for this project is a joint credit card and USB flash...

Teklehaimanot, Samson Seged

2012-01-01

39

Nanostructuring steel for injection molding tools  

Science.gov (United States)

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.

Al-Azawi, A.; Smistrup, K.; Kristensen, A.

2014-05-01

40

Nanostructuring steel for injection molding tools  

DEFF Research Database (Denmark)

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.

Kristensen, Anders

2014-01-01

 
 
 
 
41

Design and development of injection molded Fresnel lenses for point-focus photovoltaic systems  

Energy Technology Data Exchange (ETDEWEB)

A summary of work performed on a method of injection molding an 80% efficient point-focus Fresnel lens is presented. A current optical design for compression molded lenses yields a 68.5% efficiency when translated directly to injection molding. An optical design optimized for injection molding, with a mold and process developed for high efficiency Fresnel lenses, yields an 82% efficiency.

Grendol, C.L.

1987-05-01

42

Progress in Titanium Metal Powder Injection Molding  

Directory of Open Access Journals (Sweden)

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.

Randall M. German

2013-08-01

43

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

DEFF Research Database (Denmark)

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.

Tosello, Guido; Gava, Alberto

2009-01-01

44

CD injection molding I: Navier-Stokes  

Science.gov (United States)

State simplifying assumptions which can be made regarding radial injection molding of liquid polycarbonate polymer into a CD mold, and simplify the cylindrical form of the Navier-Stokes equations accordingly.

Powell, Adam C., IV

2004-08-26

45

Vacuum-injection molding of glass-metal electrical components  

Energy Technology Data Exchange (ETDEWEB)

Vacuum-injection molding is an innovative processing technique, useful in the fabrication of complex glass or glass-ceramic to metal seals. During vacuum-injection molding, molten glass is injected under pressure into the metal parts held in a mold while a vacuum is simultaneously pulled on the opposite side of the mold. The process, which is completed at low processing temperatures, improves glass flow, facilitates the removal of trapped gasses, and makes possible the fabrication of seals of complex geometry. These advantages with examples are presented. 10 figures.

Kramer, D.P.; Massey, R.T.

1983-01-01

46

Various high functional sintered materials by injection molding process; Shashutsu seikei process wo mochiita kakushu kokino shoketsu zairyo  

Energy Technology Data Exchange (ETDEWEB)

Since the Metal Injection Molding (MIM) process can offer full dense and net shaping of the three dimensional complicated parts regardless of the soft and hard metals, it can be said that it is one of the new metal processing techniques further advanced to the common power metallurgy process. Authors correctly controlled the amount of carbon and structures by using the new MIM process based on the environmental control during the de-binder (during heat-volatilizing after the solvent extraction) and sintering, finally developed a sintered material with extremely high performance, which was difficult to obtain by the common power metallurgy process. In this paper, the ferrous composite materials showing a good sliding characteristic were introduced by only adding a minority of TiN and CaF2 powers into the MIM sintered alloy steel (various stainless steel, high speed steel, maraging steel, 4100 steel, 4600 steel), high performance soft magnetic steel (Fe-Ni, Fe-Si and Sendust), and low alloy steel developed by using the MIM process. 15 refs., 12 figs., 1 tab.

Miura, H. [Kumamoto Univ. (Japan). Faculty of Engineering

1998-05-15

47

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

Science.gov (United States)

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.

Ayad, G.; Song, J.; Barriere, T.; Liu, B.; Gelin, J. C.

2007-05-01

48

Investigation of foaming behaviors in injection molding using mold pressure profile  

Science.gov (United States)

This thesis is intended to improve the understanding of foaming behaviors in various foam injection molding processes: structural foam molding, gas counter pressure molding, and gas counter pressure with mold opening. The foaming behavior in foam injection molding is different from foam extrusion in two ways. First, foaming occurs in a confined volume, which consists of a mold, whereas, it occurs in an open environment in foam extrusion. And second, while the foaming behavior in foam extrusion does not change with time once the steady state is reached, foam injection molding is on the other hand, time-dependent. These differences made it very challenging to study the foaming behaviors in foam injection molding. In this thesis, experiments were first conducted in foam extrusion to understand the effects of processing and material parameters on cell nucleation and growth behaviors. Subsequently, the knowledge obtained from the foam extrusion experiments was transferred to the foam injection molding process and the fundamental foaming mechanisms in foam injection molding were developed by conducting extensive experiments. Four processing parameters were mainly studied in this thesis: injection speed, void fraction setting (i.e., shot size), nitrogen content, and gate resistance. The experimental results revealed that the mold pressure profile during the foam injection molding process governed its foaming behaviors. Furthermore, by analyzing the mold pressure profile during the structural foam molding, it was possible to predict the achievable cell density in structural foam molding based on the foam extrusion results. When the gas counter pressure was employed, the analysis of the foaming behavior was relatively easier since the cell nucleation did not occur during the injection stage. However, the cell density that was achieved by using the gas counter pressure was generally lower than that obtained in structural foam molding due to the lower pressure drop rate caused by the use of the gas counter pressure. It was also discovered that the use of mold opening in combination with the gas counter pressure was very effective when uniform cell structure with a high void fraction was desired in addition to class-A surface quality.

Lee, John W. S.

49

Injection molding of high aspect ratio sub-100 nm nanostructures  

Science.gov (United States)

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.

Matschuk, Maria; Larsen, Niels B.

2013-02-01

50

Modelling and monitoring in injection molding  

DEFF Research Database (Denmark)

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.

Thyregod, Peter

2001-01-01

51

CENTRAL CONVEYING & AUTO FEEDING SYSTEMS FOR AN INJECTION MOLDING SHOP  

Directory of Open Access Journals (Sweden)

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.

Sanjeev Kumar

2011-08-01

52

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.

2010-01-01

53

Preparation and Characterization of Copper Feedstock for Metal Injection Molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 fr...

Goudah, G.; Ahmad, F.; Mamat, O.; Mohd. Afian Omar

2010-01-01

54

Design, analysis and simulation in injection in-mold labeling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Patcharee Larpsuriyakul

2009-01-01

55

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 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.

Søgaard, Emil Technical University of Denmark,

56

Two component micro injection molding for MID fabrication  

DEFF Research Database (Denmark)

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.

Islam, Mohammad Aminul; Hansen, Hans Nørgaard

2009-01-01

57

Injection molding of bushes made of tribological PEEK composites  

Directory of Open Access Journals (Sweden)

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.

2007-12-01

58

CAE for Injection Molding - Past, Present and the Future  

Science.gov (United States)

It is well known that injection molding is the most effective process for mass-producing discrete plastic parts of complex shape to the highest precision at the lowest cost. However, due to the complex property of polymeric materials undergoing a transient non-isothermal process, it is equally well recognized that the quality of final products is often difficult to be assured. This is particularly true when a new mold or material is encountered. As a result, injection molding has often been viewed as an art than a science. During the past few decades, numerical simulation of injection molding process based on analytic models has become feasible for practical use as computers became faster and cheaper continually. A research effort was initiated at the Cornell Injection Molding Program (CIMP) in 1974 under a grant from the National Science Foundation. Over a quarter of the century, CIMP has established some scientific bases ranging from materials characterization, flow analysis, to prediction of part quality. Use of such CAE tools has become common place today in industry. Present effort has been primarily aimed at refinements of many aspects of the process. Computational efficiency and user-interface have been main thrusts by commercial software developers. Extension to 3-dimensional flow analysis for certain parts has drawn some attention. Research activities are continuing on molding of fiber-filled materials and reactive polymers. Expanded molding processes such as gas-assisted, co-injection, micro-molding and many others are continually being investigated. In the future, improvements in simulation accuracy and efficiency will continue. This will include in-depth studies on materials characterization. Intelligent on-line process control may draw more attention in order to achieve higher degree of automation. As Internet technology continues to evolve, Web-based CAE tools for design, production, remote process monitoring and control can come to path. The CAE tools will eventually be integrated into an Enterprise Resources Planning (ERP) system as the trend of enterprise globalization continues.

Wang, Kuo K.

2004-06-01

59

Residual stress distribution in injection molded parts  

Directory of Open Access Journals (Sweden)

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 mouldpieces 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.

P. Postawa

2006-08-01

60

Structural development of HDPE in injection molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

2003-01-01

 
 
 
 
61

Binder Removal from Powder Injection Molded 316L Stainless Steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Muhammad Rafi Raza; Faiz Ahmad; Omar, M. A.; German, R. M.

2011-01-01

62

Assessment of weld line performance of PP/Talc moldings produced in hot runner injection molds  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Weld lines are weak regions in thermoplastic injection moldings caused by low molecular entanglement and unfavorable orientation. Their occurrence may lead to a significantly reduced mechanical performance of the products. Therefore, when weld lines are likely to occur in molded products, they must be taken into account during the mechanical and technological design processes. The weld lines become more critical when particulate fillers are compounded with the polymer. The performance o...

Morelli, Carolina L.; Sousa, Jose? Alexandrino; Pouzada, A. S.

2007-01-01

63

Morphology and mechanical properties of injection molded poly(ethylene terephtalate)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work reports on the relationships between processing, the morphology and the mechanical properties of an injection molded poly(ethylene terephthalate), PET. Specimens were injection molded with different mold temperatures of 30C, 50C, 80C, 100C, 120C, 150C, while maintaining constant the other operative processing parameters. The thermomechanical environment imposed during processing was estimated by computer simulations of the mold-filling phase, which allow t...

Viana, J. C.; Alves, N. M.; Mano, J. F.

2004-01-01

64

Two component micro injection molding for MID fabrication  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2008-01-01

65

TWO COMPONENT MICRO INJECTION MOLDING FOR MID FABRICATION  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2008-01-01

66

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

Directory of Open Access Journals (Sweden)

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.

A. R. Jafarian

2005-01-01

67

Metal Injection Molding of Alloy 718 for Aerospace Applications  

Science.gov (United States)

The metal injection molding process, used in the automotive, medical, and consumer markets for several decades, was investigated for application to superalloys for small, complex-shaped, aerospace components. With sufficient control on processing, inclusion risks, and chemistry, the process can successfully be applied to superalloy 718 components. Assessments included tensile and fatigue property evaluation, characterization of microstructure, and development of an AMS specification.

Ott, Eric A.; Peretti, Michael W.

2012-02-01

68

Microstructural and mechanical characterization of injection molded 718 superalloy powders  

Energy Technology Data Exchange (ETDEWEB)

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.

zgn, zgr [Bingol University, Faculty of Engineering and Architecture, Mechanical Eng. Dep., 12000 Bingol (Turkey); Glsoy, H. zkan, 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

69

Implementation and analysis of polymeric microstructure replication by micro injection molding  

Science.gov (United States)

This paper presents the adaptation of a conventional injection molding process to the mass replication of polymeric microstructures with appropriate mold design and process control. Using wet-etched silicon wafers with microstructures on the surfaces as mold inserts, we have successfully predicted, improved and optimized the replication results. The flow behaviors of polymer melts in micro mold-cavities are characterized by both simulation and experiments. Among various process parameters, temperature is identified as the key factor that decisively determines the quality of injection-molded microstructures. Based on the collected experimental and simulation results, process optimization is performed to improve replication quality and to establish guidelines for potential applications. Because of its high speed and low cost, the adaptation of the injection molding process to microfabrication will lead to a promising technology for MEMS applications.

Su, Yu-Chuan; Shah, Jatan; Lin, Liwei

2004-03-01

70

Preparation and Characterization of Copper Feedstock for Metal Injection Molding  

Directory of Open Access Journals (Sweden)

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 900C. It was observed that the feedstock containing 59 Vol. % of copper produce a free defect samples which was selected as the optimum feedstock.

Mohd. Afian Omar

2010-01-01

71

A Novel Method of Injection Molding Titanium Components  

Energy Technology Data Exchange (ETDEWEB)

We have developed a unique blend of powder injection molding feedstock materials in which only a small volume fraction of binder (< 8%) is required; the remainder of the mixture consists of the metal powder and a solid aromatic solvent. Because of the nature of the decomposition in the binder system and the relatively small amount used, the binder is eliminated almost completely from the pre-sintered component during the initial stage of a two-step heat treatment process.

Nyberg, Eric A.; Simmons, Kevin L.; Weil, K. Scott

2005-05-01

72

Injection molding tools with micro/nano-meter pattern  

DEFF Research Database (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.

Kristensen, Anders Technical University of Denmark,

73

Microcellular injection-molding of polylactide with chain-extender  

International Nuclear Information System (INIS)

The effects of adding an epoxy-based chain-extender (CE) on the properties of injection-molded solid and microcellular polylactide (PLA) were studied. PLA and PLA with 8 wt.% CE (PLA-CE) were melt-compounded using a twin-screw extruder. Solid and microcellular specimens were produced via a conventional and microcellular injection-molding process, respectively. Various characterization techniques including gel permeation chromatography, tensile testing and dynamic mechanical analysis, scanning electron microscopy and differential scanning calorimetry were applied to study the molecular weight, static and dynamic mechanical properties, cell morphology, and crystallization behavior, respectively. The addition of CE enhanced the molecular weight but decreased the crystallinity of PLA. The addition of CE also reduced the cell size and increased the cell density. Furthermore, the decomposition temperatures and several tensile properties, including specific strength, specific toughness, and strain-at-break of both solid and microcellular PLA specimens, increased with the addition of CE.

2009-05-05

74

Injection-molded nanocomposites and materials based on wheat gluten  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This is, to our knowledge, the first study of the injection molding of materials where wheat gluten (WG) is the main component. In addition to a plasticizer (glycerol), 5 wt.% natural montmorillonite clay was added. X-ray indicated intercalated clay and transmission electron microscopy indicated locally good clay platelet dispersion. Prior to feeding into the injection molder, the material was first compression molded into plates and pelletized. The filling of the circular mold via the centra...

2011-01-01

75

Replication of micro/nano-scale features by micro injection molding with a bulk metallic glass mold insert  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The development of MEMS and Microsystems needs a reliable mass production process to fabricate micro components with micro/nano scale features. In our study, we used the micro injection molding process to replicate micro/nano scale channels and ridges from a Bulk Metallic Glass (BMG) cavity insert. High density polyethylene (HDPE) was used as the molding material and Design of Experiment (DOE) was adopted to systematically and statistically investigate the relationship betwe...

Zhang, Nan; Chu, J. S.; Byrne, Cormac J.; et al.

2012-01-01

76

Modeling injection molding of net-shape active ceramic components.  

Energy Technology Data Exchange (ETDEWEB)

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

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

77

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

Directory of Open Access Journals (Sweden)

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.

A.M.A. Rani

2011-01-01

78

Binder Removal from Powder Injection Molded 316L Stainless Steel  

Directory of Open Access Journals (Sweden)

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.

M.A. Omar

2011-01-01

79

Powder metallurgical injection molding of niobium superalloys. Pulvermetallurgischer Spritzguss von Niob-Superlegierungen  

Energy Technology Data Exchange (ETDEWEB)

The new Metal Injection Molding (MIM) technique utilizes the shaping of plastic injection molding to produce of powder metallurgy parts. After applying a suitable binder, the powder can be processed in an injection molding machine as a highly filled suspension. In a subsequent step, the formed part is debound. Afterwards, the final metal part is solidified by sintering. In the work herewith presented, the MIM process was applied to two Niobium-base superalloys, i.e. C-129-Y and C-3009. (orig.)

Dropmann, M.

1993-05-01

80

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 provides the possibility to simulate the flow processes of plastic air intake manifold with different gate location and number of injection mold and to predict the position of air traps and weld lines. The location and number of the gate in injection mold are determined by comparing analysis results and avoid mold adjustment and mold repairing. Finished injection mold of plastic air intake manifold on basis of simulation is perfect.

Shiqiang Zhang

2013-01-01

 
 
 
 
81

Stability of FDTS monolayer coating on aluminum injection molding tools  

Science.gov (United States)

We have characterized perfluorodecyltrichlorosilane (FDTS) molecular coating of aluminum molds for polymer replication via injection molding (IM). X-ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energies and roughness data have been collected. Samples have been characterized immediately after coating, after more than 500 IM cycles to test durability, and after 7 months to test temporal stability. The coating was deposited in an affordable process, involving near room temperature gas phase reactions. XPS shows detectable fluorine presence on both freshly coated samples as well as on post-IM samples with estimated 30 at.% on freshly coated and 28 at.% on post-IM samples with more than 500 IM cycles with polystyrene (PS) and ABS polymer.

Cech, Jiri; Taboryski, Rafael

2012-10-01

82

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

DEFF Research Database (Denmark)

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.

Guerrier, Patrick; Tosello, Guido

2014-01-01

83

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)

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.

Ahmed N. Oumer

2013-01-01

84

Aplicao das tcnicas de planejamento e anlise de experimentos no processo de injeo plstica Application design of experiments in the injection molding process  

Directory of Open Access Journals (Sweden)

Full Text Available Experimentos industriais so realizados pelas empresas com o intuito de melhorar o desempenho dos produtos e os processos de fabricao. Nesse sentido, este trabalho tem por objetivo estudar e aplicar as tcnicas de planejamento e anlise de experimentos na melhoria da qualidade industrial. Especificamente so aplicadas as tcnicas de planejamento Fatorial Fracionado 2k-p, Metodologia de Superfcie de Resposta e Anlise de Varincia, em um processo de moldagem por injeo plstica. Com essa pesquisa experimental foi possvel identificar os nveis timos de regulagem e os parmetros mais importantes da injeo plstica: temperatura da mquina e presso de injeo. Para finalizar avaliado o procedimento de implementao das tcnicas de experimentao e as dificuldades prticas 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.

Edwin V. Cardoza Galdamez

2004-04-01

85

Replication of micro/nano-scale features by micro injection molding with a bulk metallic glass mold insert  

Science.gov (United States)

The development of MEMS and microsystems needs a reliable mass production process to fabricate micro components with micro/nano-scale features. In our study, we used the micro injection molding process to replicate micro/nano-scale channels and ridges from a bulk metallic glass (BMG) cavity insert. High-density polyethylene was used as the molding material and the design of experiment approach was adopted to systematically and statistically investigate the relationship between machine parameters, real process conditions and replication quality. The peak cavity pressure and temperature were selected as process characteristic values to describe the real process conditions that the material experienced during the filling process. The experiments revealed that the replication of ridges, including feature edge, profile and filling height, was sensitive to the flow direction; cavity pressure and temperature both increased with holding pressure and mold temperature; replication quality can be improved by increasing cavity pressure and temperature within a certain range. The replication quality of micro/nano features is tightly related to the thermomechanical history of material experienced during the molding process. In addition, the longevity and roughness of the BMG insert were also evaluated based on the number of injection molding cycles.

Zhang, N.; Chu, J. S.; Byrne, C. J.; Browne, D. J.; Gilchrist, M. D.

2012-06-01

86

FPGA-Based Multiprocessor System for Injection Molding Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Benigno Muoz-Barron; Luis Morales-Velazquez; Romero-troncoso, Rene J.; Carlos Rodriguez-Donate; Miguel Trejo-Hernandez; Benitez-rangel, Juan P.; Osornio-rios, Roque A.

2012-01-01

87

A Recurrent Neural Network for Warpage Prediction in Injection Molding  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish La inyeccin de plsticos se considera como uno de los procesos de manufactura ms flexibles y econmicos con un gran volumen de produccin de piezas de plstico. Las causas de variacin durante la inyeccin de plsticos se relacionan con el amplio nmero de factores que intervienen durante un ciclo [...] de produccin regular, tales variaciones impactan la calidad del producto final. Un problema comn de calidad en productos terminados es la presencia de deformaciones. As, este estudio tuvo como objetivo disear un sistema basado en redes neuronales recurrentes para predecir defectos de deformacin en productos fabricados por medio de inyeccin de plsticos. Se emplean cinco parmetros del proceso por ser considerados crticos y que tienen un gran impacto en la deformacin de componentes plsticos. El presente estudio hizo uso del software de anlisis finito llamado Moldflow para simular el proceso de inyeccin de plsticos para recolectar datos con el fin de entrenar y probar la red neuronal recurrente. Redes neuronales recurrentes fueron utilizadas para entender la dinmica del proceso y debido a su capacidad de memorizacin, los valores de deformacin pudieron ser predichos con exactitud. Los resultados muestran que la red diseada funciona bien en trminos de prediccin, superando aquellas predicciones generadas por redes de propagacin 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.

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

88

Residual orientation in micro-injection molded parts  

Energy Technology Data Exchange (ETDEWEB)

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.

Healy, John; Edward, Graham H.; Knott, Robert B. (Monash); (ANSTO)

2008-06-30

89

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.

2007-04-01

90

Effect of injection-molding-induced residual stress on microchannel deformation irregularity during thermal bonding  

Science.gov (United States)

Micro injection molding offers a promising approach to rapidly produce thermoplastic microfluidic substrates in large volumes. Many research works have been focused on the replication fidelity of microstructures by injection molding. However, there has not been any investigation on the effect of molded-in residual stress on microchannel deformation during the subsequent thermal bonding process. These effects could be important, because the residual stress developed due to anisotropic polymer flow orientation and inhomogeneous cooling may lead to abnormal microchannel distortion. In the direct thermal bonding process, asymmetric cross-sectional distortion was observed in well-formed microchannels aligned perpendicular to the polymer melt injection direction. This asymmetric distortion is attributed to the residual stress introduced into the substrates during molding, particularly in the surface region where microchannels are molded. Design of experiment on injection molding was carried out to reduce the residual stress in order to achieve the lowest microchannel deformation irregularity, which is a new term defined in this study. The direct thermal bonding was utilized as a feasible non-destructive indirectly quantitative method to evaluate the effect of residual stress around microchannel regarding deformation irregularity. The dominant molding parameters with positive effects were found to be melt temperature, mold temperature as well as cooling time after packing. The presence of the residual stress was also demonstrated through photoelastic stress analysis in terms of phase retardation. With improved molding condition, the absolute retardation difference around microchannels aligned parallel and perpendicular to the molding direction could be tuned to the same level, which indicates that the molded-in residual stresses have been moderated.

Yu, H.; Tor, S. B.; Loh, N. H.; Asundi, A. K.

2013-01-01

91

Characterization and Simulation of Material Distribution and Fiber Orientation in Sandwich Injection Molded Parts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work, the material distribution, structure of fiber orientation and fiber attrition in sandwich and push-pull injection molded short fiber composites are investigated, regarding the effect of fiber content and processing parameters, given its direct relevance to mechanical properties. The prediction of the tensile strength of conventional, sandwich and push-pull injection molded short fiber composites are derived by an analytical method of modified rule of mixtures as a...

Patcharaphun, Somjate

2006-01-01

92

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

Directory of Open Access Journals (Sweden)

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.

Kanaga Lakshmi

2014-03-01

93

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)

1987-01-01

94

Evaluation of novel tooling for nanoscale injection molding  

Science.gov (United States)

Injection molding technology is one of the most promising candidates for the economically viable manufacturing of nanoscale parts, but the composition and surface properties of tooling materials become more critical as the size of the molded features decreases. In the study, the effect of novel tooling with micro and nanoscale features was investigated by employing this tooling as inserts for micro injection molding of polycarbonate. Parts molded from etched silicon wafers with pattern depths of 300 nm and widths of 200 to 980 nm showed a significant decrease in replication quality with the size the features, probably because polymer adhered to the tooling surface. Silicon tooling from a different source and titanium-coated gallium arsenide tooling produced higher quality replication. The replication quality from the silicon tooling, however, was constant over 3000 molding cycles and coated gallium arsenide inserts survived the molding pressures; (the uncoated gallium arsenide fractured). These findings suggest that modifications to the insert surfaces will allow for viable tooling for injection molding of plastic parts with nanoscale features.

Yoon, Sung-hwan; Srirojpinyo, Chinnawat; Lee, Jun S.; Mead, Joey L.; Matsui, Shinji; Barry, Carol M. F.

2005-05-01

95

Design and Manufacturing of a Modular Prototype Mold to be employed in Micro Injection Molding Experiments  

Science.gov (United States)

The use of polymer replication methods such as Micro Injection Molding (MIM), can reduce drastically production costs of Micro Electro Mechanical Systems (MEMS) at medium or large scale. The MIM replication of micro-features with high aspect ratios is a problem which requires a complex molding cycle, and further flow modelling techniques, that have to be more deeply investigated. A special approach to this problem is developed in the present work, in which a new modular mold is designed to be employed in MIM experiments. The new design considers important factors such as mold temperature and cavities venting that are determinant in the filling of micro-features. But the main goal of the proposed system is the ability to replace the investigated cavity in a short period of time, without discarding the most of the mold structure components, becoming very suitable equipment for MIM research activity.

Marquez, J. J.; Rueda, J.; Chaves, M. L.

2009-11-01

96

Experiments and Simulation of Injection Molding with Microstructures  

Science.gov (United States)

Injection molding has the potential for economical mass-production of polymer products with microstructures. Conventional 2D midplane simulations using the Hele-Shaw approximation are not able to describe the local flow for the microstructures. A hybrid 2D simulation code combining solutions of the general momentum equation in the microstructure region and the Hele-Shaw model in the main flow region is developed. This method is able to obtain a good resolution and requires less computational time than the full 3D momentum equation approach. The mold-melt heat transfer coefficient and injection speed are found be the very important factors to determine the filling depth. A series of injection molding experiments is carried out and comparison is made between the experimental measurements and simulation results. A commercial simulation code DEFORM is also tested in the simulation of micro injection molding because it can calculate the stress distribution in the mold piece and mold deformation. The rheology data is input as the plastic property of the material.

Yu, Liyong; Xu, Guojun; Lee, L. James; Koelling, Kurt W.

2004-06-01

97

Evaluation of stability for monolayer injection molding tools coating  

DEFF Research Database (Denmark)

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.

Cech, Jiri; Taboryski, Rafael J.

2012-01-01

98

CREEP MODELING FOR INJECTION-MOLDED LONG-FIBER THERMOPLASTICS  

Energy Technology Data Exchange (ETDEWEB)

This paper proposes a model to predict the creep response of injection-molded long-fiber thermoplastics (LFTs). The model accounts for elastic fibers embedded in a thermoplastic resin that exhibits the nonlinear viscoelastic behavior described by the Schaperys model. It also accounts for fiber length and orientation distributions in the composite formed by the injection-molding process. Fiber length and orientation distributions were measured and used in the analysis that applies the Eshelbys equivalent inclusion method, the Mori-Tanaka assumption (termed as the Eshelby-Mori-Tanaka approach) and the fiber orientation averaging technique to compute the overall strain increment resulting from an overall constant applied stress during a given time increment. The creep model for LFTs has been implemented in the ABAQUS finite element code via user-subroutines and has been validated against the experimental creep data obtained for long-glass-fiber/polypropylene specimens. The effects of fiber orientation and length distributions on the composite creep response are determined and discussed.

Nguyen, Ba Nghiep; Kunc, Vlastimil; Bapanapalli, Satish K.

2008-06-30

99

Feed stock preparation and achievement of shape complexity using powder injection molding (PIM)  

International Nuclear Information System (INIS)

Powder injection molding is one of the near net shape processing (NNSP) techniques used to produce geometrically complex shapes that need very little or no machining. This study presents the comparative study of feedstock preparation for Metal and Ceramic Injection Molding from the view point of achievement of shape complexity. Different variables of feedstock are studied, such as the role of binder, processing temperature, role of additives and the starting powder attributes on shape complexity. In this study, different binder systems; paraffin wax, polyethylene glycol, stearic acid, several thermoplastic resins and powders Fe and Al/sub 2/O/sub 3/ are studied. The differences between metal injection molding and ceramic injection molding are clearly emphasized. A major focus of this study is to attain the requisite engineering properties by a control of microstructure using different dies with increasing shape complexity. Powder is mixed with the binder system, the mix is injection molded into the desired shape cavity, the molded part is de-bound and after debinding it is sintered to produce high density products. (author)

2007-01-01

100

Metal-injection molding of tungsten heavy alloys: SBIR Phase 1. Final report, 20 Aug 90-20 Jun 91  

Energy Technology Data Exchange (ETDEWEB)

The objective of this study is to investigate the feasibility of injection molding tungsten heavy alloys into net or near-net shape parts. The focus was to demonstrate that powder injection molding can provide parts with equivalent or superior sintered material properties to those that have been achieved for press/sintering heavy alloys of similar compositions. In addition, geometric shrinkage and key process variables were identified and analyzed. This investigation was divided into twelve tasks including elemental particle analysis using laser diffraction; powder blending; solid loading curve; feedstock rheology; feedstock mixing; prototype test mold; injection molding; furnacing (thermal debinding and sintering); and mechanical properties.

Allen, G.M.

1991-10-01

 
 
 
 
101

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)

2011-11-01

102

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.

2011-12-01

103

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)

2000-08-20

104

Three dimensional modeling of metal powder injection molding  

Energy Technology Data Exchange (ETDEWEB)

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)

Ilinca, F.; Hetu, J-F.; Derdouri, A. [National Research Council of Canada, Industrial Material Inst., Boucherville, Quebec (Canada); Holmes, B. [Columbia Powder Injection Molding, Surrey, British Columbia (Canada); Scott, C.; Stevenson, J. [Honeywell PowerFlo Technologies, Morristown, New Jersey (United States)

2000-07-01

105

Multiple Performance Optimization for the Best Metal Injection Molding Green Compact  

Directory of Open Access Journals (Sweden)

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.

M.R. Harun

2011-01-01

106

Effects of adding injection-compression to rapid heat cycle molding on the structure of a light guide plate  

Science.gov (United States)

This study investigates the effects of adding injection-compression to rapid heat cycle molding (RHCM) (rapid heat cycle injection-compression molding (RICM)) on the physical quality and optical anisotropy of a molded light guide plate (LGP). Transcription ratio of microstructure, uniformity of part thickness and birefringence were experimentally evaluated on a 7 inch LGP of nominal thickness of 1.12 mm (including a microstructure array of 30 m diameter and 14 m height). The designed mold was equipped with rapid heating and compressing facilities and a microstructured nickel stamper was fabricated by UV LIGA process. In addition, to investigate the efficacy of RICM, experiments involving conventional injection molding (CIM), ICM, and RHCM were conducted in parallel with RICM using the same mold. RHCM and RICM yielded excellent transcription ratios for the microstructure, while CIM and RICM provided high thickness uniformity and low birefringence. Thus, RICM obtains high transcription ratio of microstructure, uniform thickness and low birefringence.

Hong, Seokkwan; Min, Inki; Yoon, Kyunghwan; Kang, Jeongjin

2014-01-01

107

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Effects of injection temperature on thermal degradation and porosity of the bagasse/polypropylene injection molding composites were studied. Above 185 C, 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 in...

2010-01-01

108

FPGA-Based Multiprocessor System for Injection Molding Control  

Science.gov (United States)

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.

Munoz-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

109

FPGA-Based Multiprocessor System for Injection Molding Control  

Directory of Open Access Journals (Sweden)

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.

Roque A. Osornio-Rios

2012-10-01

110

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

Directory of Open Access Journals (Sweden)

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 m were successfully filled and demolded.

2011-11-01

111

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

DEFF Research Database (Denmark)

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

Jensen, Marie Pødenphant; Marie, Rodolphe

2014-01-01

112

Evaluation of W-Cu metal matrix composites produced by powder injection molding and liquid infiltration  

Energy Technology Data Exchange (ETDEWEB)

The near net shape processing of tungsten-copper metal matrix composites by powder injection molding and liquid copper infiltration was studied in this paper. In this technique, powder injection molded bimetallic components were produced. The component was debinded and subsequently heated to an elevated temperature. This facilitated the sintering of the high melting point metal and the liquidation of the lower melting point for infiltration into the preform of the former. Feasibility of this method in the manufacture of tungsten-copper metal matrix composites with high percentage copper, up to 38 wt.%, was demonstrated and mechanical properties were evaluated in this study.

Ho, P.W. [National University of Singapore, Department of Mechanical Engineering, 9 Engineering Drive 1, Singapore 117576 (Singapore); Singapore Institute of Manufacturing Technology (SIMTech), 71 Nanyang Drive, Singapore 638075 (Singapore)], E-mail: g0403647@nus.edu.sg; Li, Q.F. [Singapore Institute of Manufacturing Technology (SIMTech), 71 Nanyang Drive, Singapore 638075 (Singapore); Fuh, J.Y.H. [National University of Singapore, Department of Mechanical Engineering, 9 Engineering Drive 1, Singapore 117576 (Singapore)

2008-06-25

113

Anlise do desenvolvimento morfolgico da blenda polimrica PBT/ABS durante as etapas de mistura por extruso e moldagem por injeo Analysis of the morphological development of PBT/ABS blends during the extrusion and injection molding processes  

Directory of Open Access Journals (Sweden)

Full Text Available O enfoque principal deste trabalho foi observar o desenvolvimento da morfologia de fases da blenda binria PBT/ABS e desta blenda compatibilizada pela adio de um copolmero acrlico reativo, durante a etapa de mistura por extruso e de moldagem por injeo. A evoluo da morfologia das blendas, durante a etapa de mistura, foi analisada atravs do uso de amostras coletadas de uma extrusora de rosca dupla co-rotacional, com acessrio especialmente projetado para coleta in line. A morfologia observada nas amostras obtidas por injeo foi realizada utilizando amostras retiradas de corpos de prova moldados. As amostras obtidas por extruso e por moldagem por injeo foram posteriormente preparadas atravs de crio-ultramicrotomia e observadas atravs de microscopia eletrnica de transmisso (TEM. Uma "Funo Disperso" foi desenvolvida neste trabalho para comparar as diversas morfologias sob diferentes condies de processamento e de compatibilizao. A adio de compatibilizante favorece a formao de uma morfologia de domnios de ABS dispersos em PBT, ao longo do canho da extrusora, e previne satisfatoriamente o fenmeno de coalescncia destes domnios durante o processo de moldagem por injeo. A funo disperso foi utilizada principalmente para mostrar a tendncia da evoluo morfolgica 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.

Edson N. Ito

2004-06-01

114

Anlise do desenvolvimento morfolgico da blenda polimrica PBT/ABS durante as etapas de mistura por extruso e moldagem por injeo / Analysis of the morphological development of PBT/ABS blends during the extrusion and injection molding processes  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O enfoque principal deste trabalho foi observar o desenvolvimento da morfologia de fases da blenda binria PBT/ABS e desta blenda compatibilizada pela adio de um copolmero acrlico reativo, durante a etapa de mistura por extruso e de moldagem por injeo. A evoluo da morfologia das blendas, du [...] rante a etapa de mistura, foi analisada atravs do uso de amostras coletadas de uma extrusora de rosca dupla co-rotacional, com acessrio especialmente projetado para coleta in line. A morfologia observada nas amostras obtidas por injeo foi realizada utilizando amostras retiradas de corpos de prova moldados. As amostras obtidas por extruso e por moldagem por injeo foram posteriormente preparadas atravs de crio-ultramicrotomia e observadas atravs de microscopia eletrnica de transmisso (TEM). Uma "Funo Disperso" foi desenvolvida neste trabalho para comparar as diversas morfologias sob diferentes condies de processamento e de compatibilizao. A adio de compatibilizante favorece a formao de uma morfologia de domnios de ABS dispersos em PBT, ao longo do canho da extrusora, e previne satisfatoriamente o fenmeno de coalescncia destes domnios durante o processo de moldagem por injeo. A funo disperso foi utilizada principalmente para mostrar a tendncia da evoluo morfolgica 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.

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

115

Net shaping of tungsten components by micro powder injection molding  

International Nuclear Information System (INIS)

For future fusion power plants, a He-cooled Divertor design has been developed by the Forschungszentrum Karlsruhe. The Divertor as one of the plasma facing components has to withstand high heat loads of 10 MW/m2 as well as sputtering due to ion impact on the surface of the Divertor. Tungsten is considered the most promising material to be used for this application. Because of the high hardness of tungsten, fabrication of these parts by standard shaping technologies for steels such as milling is, depending on the component, either difficult or even impossible. The objective of this work is the adoption of tungsten on powder injection moulding (PIM) as a widely used mass production method for net shaping of micro structured ceramic and metal parts. It is well known that for design accuracy and good surface quality as well as high sinter activity the particle size of powders applied to micro PIM should be as small as possible while the powder content of the feedstock should be as high as possible but at least 50 vol.%. In case of tungsten, industrial available powders are usually highly agglomerated. In order to provide a homogeneous feedstock with a solid load above 50 vol.%, powders applied to PIM have to be deagglomerated. Depending on the grain size, tungsten shows different kinds of agglomeration states. Ultra fine grain sizes below 1 ?m build sponge like agglomerates, while bigger grain sizes result in agglomerates being built of individually grown crystals. It was found that pre-milling of powders with a grain size of 0,7 ?m FSSS has nearly no effect on the resulting viscosity whereas in case of 3 ?m FSSS deagglomeration drastically improves the viscosity and the processability of the feedstock. For further improvement of the feedstock, in this paper grain size dependent variations of the solid load shall be discussed to define an optimised grain size for Micro PIM of tungsten components. For initial PIM experiments, a first feedstock based on a tungsten powder with a grain size of 2,5 ?m FSSS and a solid load of 55 vol.% was developed and a microstructured cavity for a gear housing as well as Slot Arrays with 24 Slots were injection molded. Further on, tensile test bars and charpy-test specimens were replicated to provide mechanical data of tungsten samples being prepared by PIM. By debinding and sintering of injection molded tungsten parts, a density of 96% and a residual carbon content <0,003 wt.% was achieved. (author)

2006-09-11

116

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

Science.gov (United States)

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 microfluidic 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.

Jung, Woo-Chul; Heo, Young-Moo; Yoon, Gil-Sang; Shin, Kwang-Ho; Chang, Sung-Ho; Kim, Gun-Hee; Cho, Myeong-Woo

2007-01-01

117

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

Directory of Open Access Journals (Sweden)

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.

Myeong-Woo Cho

2007-08-01

118

Integrated mold/surface-micromachining process  

Energy Technology Data Exchange (ETDEWEB)

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.

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

1996-03-01

119

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

Directory of Open Access Journals (Sweden)

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 Taguchis 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.

M.H.I Ibrahim

2010-06-01

120

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.

2010-01-01

 
 
 
 
121

Flow-induced birefringence: the hidden PSF killer in high performance injection-molded plastic optics  

Science.gov (United States)

A 7-mm OD, NA = 1 water immersion injection-molded plastic endoscope objective has been fabricated for a laser scanning fiber confocal reflectance microscope (FCRM) system specifically designed for in vivo detection of cervical and oral pre-cancers. Injection-molded optics was selected for the ability to incorporate aspheric surfaces into the optical design and its high volume capabilities. Our goal is high performance disposable endoscope probes. This objective has been built and tested as a stand-alone optical system, a Strehl ratio greater than 0.6 has been obtained. One of the limiting factors of optical performance is believed to be flow-induced birefringence. We have investigated different configurations for birefringence visualization and believe the circular polariscope is most useful for inspection of injection-molded plastic optics. In an effort to decrease birefringence effects, two experiments were conducted. They included: (1) annealing of the optics after fabrication and (2) modifying the injection molding prameters (packing pressures, injection rates, and hold time). While the second technique showed improvement, the annealing process could not improve quality without physically warping the lenses. Therefore, to effectively reduce flow-induced birefringence, molding conditions have to be carefully selected. These parameters are strongly connected to the physical part geometry. Both optical design and fabrication technology have to be considered together to deliver low birefringence while maintaining the required manufacturing tolerances. In this paper we present some of our current results that illustrate how flow-induced birefringence can degrade high performance injection-molded plastic optical systems.

Chidley, Matthew D.; Tkaczyk, Tomasz; Kester, Robert; Descour, Michael R.

2006-03-01

122

Foam injection molding of poly(lactic acid) with physical blowing agents  

Science.gov (United States)

Foam injection molding uses environmental friendly blowing agents under high pressure and temperature to produce parts having a cellular core and a compact solid skin (the so-called "structural foam"). The addition of a supercritical gas reduces the part weight and at the same time improves some physical properties of the material through the promotion of a faster crystallization; it also leads to the reduction of both the viscosity and the glass transition temperature of the polymer melt, which therefore can be injection molded adopting lower temperatures and pressures. These aspects are of extreme interest for biodegradable polymers, which often present a very narrow processing window, with the suitable processing temperatures close to the degradation conditions. In this work, foam injection molding was carried out by an instrumented molding machine, able to measure the pressure evolution in different positions along the flow-path. The material adopted was a biodegradable polymer, namely the Poly(lactic acid), PLA. The effect of a physical blowing agent (PBA) on the viscosity was measured. The density reduction and the morphology of parts obtained by different molding conditions was assessed.

Pantani, R.; Sorrentino, A.; Volpe, V.; Titomanlio, G.

2014-05-01

123

Surface topographic characterization for polyamide composite injection molds made of aluminum and copper alloys.  

Science.gov (United States)

In order to ensure flexibility and rapid new product development, the mold industry made use of soft materials for cavity inserts in injection molds. However, materials of this kind are prone to wear. This article analyzes the topographic characterization of the surface and wear processes in injection molds cavities. Two materials have been used to produce the cavities: aluminum alloy EN AW?6082 T4 and copper alloy Cu Zn39 Pb3. The surface topography was measured with the use of optical interferometry profiling technology; roughness and surface parameters were determined according to ISO 4287, ISO 25178, and EUR 15178N. In order to complete this research, an experimental part with different thicknesses and shapes was designed, and cavity inserts of aluminum and copper were made. Polyamide PA6, with 30% fiberglass reinforcement, was employed in the experimental procedure. Measurements of cavity mold surfaces were performed after 9,200 cycles on each mold and at different locations on the mold. The surface measurement was made with a white light vertical scanning interferometry, also known as coherence scanning interferometry (ISO DIS 25178?604). The results are analyzed and differences between the two types of cavity inserts materials are discussed. PMID:23447356

Pereira, A; Hernndez, P; Martinez, J; Prez, J A; Mathia, T G

2014-01-01

124

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

DEFF Research Database (Denmark)

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.

Menotti, Stefano; Hansen, Hans Nørgaard

2013-01-01

125

Pressureless sintering behavior of injection molded alumina ceramics  

Directory of Open Access Journals (Sweden)

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.

Liu W.

2014-01-01

126

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Composites of high density polyethylene (HDPE) with hydroxyapatite (HAthe 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 combin...

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

2002-01-01

127

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Oumer, Ahmed N.; Othman Mamat

2013-01-01

128

A Simulation Study of Conformal Cooling Channels in Plastic Injection Molding  

Directory of Open Access Journals (Sweden)

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.

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

2013-09-01

129

Damage Modeling Of Injection-Molded Short- And Long-Fiber Thermoplastics  

International Nuclear Information System (INIS)

This article applies the recent anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model for predicting fiber orientation and a new damage model for injection-molded long-fiber thermoplastics (LFTs) to analyze progressive damage leading to total failure of injection-molded long-glass-fiber/polypropylene (PP) specimens. The ARD-RSC model was implemented in a research version of the Autodesk Moldflow Plastics Insight (MPI) processing code, and it has been used to simulate injection-molding of a long-glass-fiber/PP plaque. The damage model combines micromechanical modeling with a continuum damage mechanics description to predict the nonlinear behavior due to plasticity coupled with damage in LFTs. This model has been implemented in the ABAQUS finite element code via user-subroutines and has been used in the damage analyses of tensile specimens removed from the injection-molded long-glass-fiber/PP plaques. Experimental characterization and mechanical testing were performed to provide input data to support and validate both process modeling and damage analyses. The predictions are in agreement with the experimental results.

2009-09-15

130

DAMAGE MODELING OF INJECTION-MOLDED SHORT- AND LONG-FIBER THERMOPLASTICS  

Energy Technology Data Exchange (ETDEWEB)

This article applies the recent anisotropic rotary diffusion reduced strain closure (ARD-RSC) model for predicting fiber orientation and a new damage model for injection-molded long-fiber thermoplastics (LFTs) to analyze progressive damage leading to total failure of injection-molded long-glass-fiber/polypropylene (PP) specimens. The ARD-RSC model was implemented in a research version of the Autodesk Moldflow Plastics Insight (MPI) processing code, and it has been used to simulate injection-molding of a long-glass-fiber/PP plaque. The damage model combines micromechanical modeling with a continuum damage mechanics description to predict the nonlinear behavior due to plasticity coupled with damage in LFTs. This model has been implemented in the ABAQUS finite element code via user-subroutines and has been used in the damage analyses of tensile specimens removed from the injection-molded long-glass-fiber/PP plaques. Experimental characterization and mechanical testing were performed to provide input data to support and validate both process modeling and damage analyses. The predictions are in agreement with the experimental results.

Nguyen, Ba Nghiep; Kunc, Vlastimil; Bapanapalli, Satish K.; Phelps, Jay; Tucker III, Charles L.

2009-10-30

131

Carbon Nanotubes Reinforced Copper Matrix Nanocomposites via Metal Injection Molding Technique  

Directory of Open Access Journals (Sweden)

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 170C. 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 (900-1050C 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.

Norani M. Mohamed

2012-01-01

132

A X-ray study of ?-phase and molecular orientation in nucleated and non-nucleated injection molded polypropylene resins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The development of ? and ?-phases and the molecular orientation of injection molded disks of two isotactic polypropylene (i-PP) resins were studied by wide angle X-ray diffraction (WAXD) and pole figures. A nucleated (NPP) and non-nucleated (HPP) polymers were analyzed. The main proposal of this article was the comprehensive study of the interrelations between the processing conditions, phase contents and PP ?-phase molecular orientation of injection molded PP resins. In both r...

Marcia Maria Favaro; Marcia Cristina Branciforti; Rosario Elida Suman Bretas

2009-01-01

133

Viscosity and powder dispersion in ceramic injection molding mixtures  

Energy Technology Data Exchange (ETDEWEB)

Particle dispersion in ceramic injection molding mixtures is investigated from the shear viscosity data of the mixtures. The degree of agglomeration of the mixture is examined using the Krieger and Dougherty equation on the viscosity for a concentrated suspension. The number of particles in a single agglomerate is evaluated by the shape factor parameter of suspended particles in the Krieger and Dougherty model with the scaling law of fractal analysis on particle agglomerates. The number of particles per agglomerate predicted are four particles for a zirconia sample, and for a alumina sample the particles are in a well dispersed state. These values of agglomeration in the molding mixtures predicted by the viscometric method are almost consistent with those predicted by the visualized technique. (author)

Okada, K.; Nagase, Y. [Kurashiki Univ. of Science and the Arts, Okayama (Japan). Dept. of Chemical Tech.

2000-02-01

134

A method for patterned in situ biofunctionalization in injection-molded microfluidic devices.  

Science.gov (United States)

We developed a method to modify the surface in injection molded polymer microdevices prior to bonding and to pattern biomolecules in the completed microsystem in situ by a sequence of simple perfusion steps directly before utilization of the device. This method is compatible with production technology such as injection molding and bonding processes currently employed in the fabrication of polymer microsystems. It solves the problem of the inherent incompatibility of biomolecules with microfabrication technology as it allows for the biofunctionalization step to be performed after completion of the microsystem. Injection molded cyclic olefin copolymer (COC) microfluidic chips were modified by irradiating the surface with UV-light at lambda = 185 nm. This results in the formation of stable acidic groups which were further modified by binding of the extracellular matrix protein collagen type I. Non-irradiated surfaces were modified by binding of Pluronic F-127 to become non-adhesive. Density of acid groups decreases to 50% within 45 days and to 25% within 19 weeks after irradiation. However, even then the remaining density of functional groups was shown to be sufficient to bind proteins and promote cell adhesion. Selective adhesion of primary hepatocytes on surfaces patterned by UV-irradiation and a biofunctional coating with collagen type I were demonstrated in injection molded microsystems. PMID:20676423

Schtte, Julia; Freudigmann, Christian; Benz, Karin; Bttger, Jan; Gebhardt, Rolf; Stelzle, Martin

2010-10-01

135

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

Science.gov (United States)

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.

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

2014-05-01

136

A Study of Micro Injection Molding for High-Aspect-Ratio Optical Fiber Ferrules  

Science.gov (United States)

This study focused on manufacture of high-aspect-ratio optical fiber ferrules by micro thermoplastic injection molding technique. In the past, the optical fiber connectors were produced by ceramic powder injection molding and subsequent precision grinding process. In this work, plastic micro injection molding technique was attempted to manufacture net-shaped products at once. Each ferrule has a micro through hole in the center. The hole's diameter is 125+/-1?m, and its length is 9mm. During micro molding, how to keep the micro core pin at the center becomes a critical issue. In this work, a guiding slide system is introduced to hold the micro pin continuously. And the slide movement was controlled by a spring behind it. Such a guiding system can help reduce mis-alignment of the micro core pin and increase its life time. Taguchi's design of experiment was used to evaluate the effects of processing parameters on final properties. Experimental results reveal that the higher the spring force, the larger the product weight and the lower the shrinkage. In order to obtain better uniformity of diameters at different locations, diameters at three locations were measured. Measured data showed the shrinkage of diameter in the middle is greater than those at two ends. It is because the two ends cooled faster than the center region. This can be improved by applying higher mold temperature or appropriate holding pressure or holding time. The new design concept can be applied in molding micro tubes, especially for the high aspect ratio cases.

Lin, Zheng-Guan.; Tseng, Shi-Chang; Wang, James; Su, Yi-Chung

2004-06-01

137

Ion channel recordings on an injection-molded polymer chip.  

Science.gov (United States)

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. PMID:24154831

Tanzi, Simone; Matteucci, Marco; Christiansen, Thomas Lehrmann; Friis, Sren; Christensen, Mette Thylstrup; Garnaes, Joergen; Wilson, Sandra; Kutchinsky, Jonatan; Taboryski, Rafael

2013-12-21

138

A micro powder injection molding apparatus for high aspect ratio metal micro-structure production  

Science.gov (United States)

A new variotherm molding apparatus is presented in this paper for the fabrication of high aspect ratio 316L stainless steel micro-structures using micro powder injection molding (?PIM) technology. The molding apparatus prototype includes an injection mold in which a silicon insert with an array of 24 24 (576) microcavities is mounted, a set of rapid tempering systems for the mold and a set of vacuum systems. The key advantage of this molding apparatus lies in the real-time monitoring and rapid adjustment of the mold cavity temperature during injection molding and part ejection, which makes molding and demolding of high aspect ratio green micro-structures possible. For example, incomplete filling occurs while injection molding micro-structures of 60 m height 191 m with an aspect ratio of 3.2 using a conventional mold. In comparison, smaller micro-structures with higher aspect ratio are produced successfully in the case of the new molding apparatus, e.g. micro-structures of 40 m height 174 m with an aspect ratio of 4.35 and 20 m height 160 m with an aspect ratio of 8 were molded successfully.

Fu, Gang; Tor, Shubeng; Loh, Ngiaphiang; Tay, Beeyen; Hardt, David E.

2007-09-01

139

Process for preparing sand cores and molds  

Energy Technology Data Exchange (ETDEWEB)

An improved process for preparing foundry cores and molds using a foundry aggregate and a binder therefor wherein the aggregate is mixed with an aqueous suspension of cereal flour and then with a core oil, the improvement comprising mixing the aggregate with phosphoric acid or sulfuric acid before mixing with the aqueous suspension of the cereal flour.

Varnum, N.C.; Kraemer, J.F.

1984-11-27

140

Adhesion strength between thermoplastics and its polyurethane coating made by using the technology combination of injection molding and reaction injection molding  

Science.gov (United States)

A complete equipment for injection molding (IM) of a thermoplastic (TP) carrier and reaction injection molding (RIM) of polyurethane (PUR) coatings including IM and RIM machines, a color module for PUR, and a robot was built up. A modularly composed sliding split mold was constructed and manufactured allowing different parts including thicker (2 mm thickness) soft touch and thin (0.4 mm) lacquer PUR coatings. As TP PC/ABS and PA6 GF15 compounds were used, and aromatic and aliphatic PUR systems as well. From the parts made by IM+RIM, test specimens for peel force measurements were cut. These investigations were performed prior and after ageing under climatic conditions @ 50 % RH and temperature changes between -30 C and 90 C. By varying IM processing parameters, we have found that mold and TP temperatures are particularly important for the adhesion strength between TP and PUR. The waiting time between the end of TP cooling and PUR injection has a minor influence on its mean value. However, to short waiting times may result in inhomogeneous adhesion. It was surprising that surface defects of the TP carrier leads also to inhomogeneous adhesion. We have observed that ageing may cause an increase and decrease of adhesions strength depending on the TP+PUR system used. We have found that the results are valid only for the actual TP and PUR combination. A generalization seems to be inappropriate, hence, the actual combination should be investigated to prevent unwanted surprises when the coated TP part is in its application.

Blo, P.; Bhme, A.; Mller, J.; Krajewsky, P.; Michaelis, J.

2014-05-01

 
 
 
 
141

Fiber Reinforcement in Injection Molded Nylon 6/6 Spur Gears  

Science.gov (United States)

Injection molded polymer composite gears are being used in many power and or motion transmission applications. In order to widen the utilization of reinforced polymers for precision motion transmission and noise less applications, the accuracy of molded gears should be increased. Since the injection molded gear accuracy is significantly influenced by the material shrinkage behaviour, there is a need to understand the influence of fiber orientation and gate location on part shrinkage behaviour and hence the gear accuracy. Unreinforced and 20% short glass fiber reinforced Nylon 6/6 spur gears were injection molded in the laboratory and computer aided simulations of gear manufacturing was also carried out. Results of the mold flow simulation of gear manufacturing were correlated with the actual fiber orientation and measured major geometrical parameters of the molded gears. Actual orientation of the fibers near the tooth profile, weld line region and injection points of molded gears were observed using optical microscope and correlated with predicted fiber orientation.

Senthilvelan, S.; Gnanamoorthy, R.

2006-07-01

142

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

Directory of Open Access Journals (Sweden)

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.

J. Soulestin

2012-03-01

143

Injection Molded Optical Lens Using a Heat Resistant Thermoplastic Resin with Electron Beam Cross-Linking  

Science.gov (United States)

The poor heat resistant properties of a transparent thermoplastic resin was improved by electron beam irradiation cross-linking. A correcting aspheric lens for a 635-nm laser diode was fabricated using an injection molding machine, and was irradiated with an electron beam. The near field pattern (NFP), the far field pattern (FFP) at the focus position and the transmittance of the lens did not change after exposure to a 260 C reflow process for 60 s.

Tomomi Sano,; Yoshitomo Iyoda,; Takayuki Shimazu,; Michiko Harumoto,; Akira Inoue,; Makoto Nakabayashi,; Hiroshi Ito,

2010-05-01

144

Injection molding of a starch/EVOH blend aimed as an alternative biomaterial for temporary applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Biodegradable polymers show great potential to be used as materials for temporary implants and bone replacement applications in orthopedics. However, its use in high load-bearing applications will depend on the successful development of biodegradable implants with a mechanical performance matching that of human bone. This article describes the optimization of the injection molding process of an alternative biodegradable starch-based polymer aimed at biomedical applications. A blend of starch ...

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

2000-01-01

145

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

Science.gov (United States)

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.

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

2014-05-01

146

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)

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.

K.R. Jamaludin

2011-01-01

147

Development of Defects Free Stainless Steel Parts Using Powder Injection Molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Muhammad Rafi Raza; Faiz Ahmad; Omar, M. A.; Muhsan, Ali S.

2013-01-01

148

Structure development and control of injection-molded hydroxylapatite-reinforced starch/EVOH composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article reports on the development of novel composites of starch-based polymers reinforced with hydroxylapatite (HA). Two different grades of blends of starch and ethylene vinyl alcohol copolymers were reinforced with up to 30% (wt) of sintered and nonsintered HA. The initial compounding stage was carried out either in a rotating drum or by twin-screw extrusion (TSE). Compounds were injection molded using both conventional molding and a shear-controlled orientation in injection molding (...

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

1997-01-01

149

Improvement Performance of the Filling Step in Injection Mold through Vibration  

Directory of Open Access Journals (Sweden)

Full Text Available 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 changed 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.

Trejo-Hernndez M.

2012-10-01

150

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

Directory of Open Access Journals (Sweden)

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.

Norhamidi Muhamad

2008-08-01

151

Effect of cross sectional geometry on PDMS micro peristaltic pump performance: comparison of SU-8 replica molding vs. micro injection molding.  

Science.gov (United States)

Two different fabrication methods were employed to fabricate micropumps with different cross-sectional channel geometries. The first was to fabricate rectangular cross-sectional microchannel geometries using the well known fabrication method of replica molding (REM). The second, and far less utilized fabrication technique, was to create microchannel molds using an in-house fabricated handheld micro injection molding apparatus. The injection mold apparatus was designed for use with elastomeric room temperature vulcanization (RTV) polymers, as opposed to most other injection molding machines, which are designed for use with thermoplastic polymers. The injection mold's bottom plate was used as a microchannel molding template. The molding template was created by threading a small-diameter wire (150 ?m or less) through the injection mold's bottom plate, with subsequent adhesion and smoothing of a thin piece of aluminum foil over the wire-raised injection mold template. When molded against, the template produced a rounded/Gaussian-shaped PDMS microchannel. The design of the injection mold will be presented, along with a direct comparison for micropump performance metrics such as flow rate, valving characteristics, and maximum backpressures attainable for each of the respective micropump channel geometries. PMID:23917263

Graf, Neil J; Bowser, Michael T

2013-10-01

152

Imprinted and injection-molded nano-structured optical surfaces  

DEFF Research Database (Denmark)

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.

Christiansen, Alexander Bruun Technical University of Denmark,

2013-01-01

153

An Elastic-Plastic and Strength Prediction Model for Injection-Molded Long-Fiber Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper applies a recently developed model to predict the elastic-plastic stress/strain response and strength of injection-molded long-fiber thermoplastics (LFTs). The model combines a micro-macro constitutive modeling approach with experimental characterization and modeling of the composite microstructure to determine the composite stress/strain response and strength. Specifically, it accounts for elastic fibers embedded in a thermoplastic resin that exhibits the elastic-plastic behavior obeying the Ramberg-Osgood relation and J-2 deformation theory of plasticity. It also accounts for fiber length, orientation and volume fraction distributions in the composite formed by the injection-molding process. Injection-molded-long-glass-fiber/polypropylene (PP) specimens were prepared for mechanical characterization and testing. Fiber length, orientation, and volume fraction distributions were then measured at some selected locations for use in the computation. Fiber orientations in these specimens were also predicted using an anisotropic rotary diffusion model developed for LFTs. The stress-strain response of the as-formed composite was computed by an incremental procedure that uses the Eshelbys equivalent inclusion method, the Mori-Tanaka assumption and a fiber orientation averaging technique. The model has been validated against the experimental stress-strain results obtained for these long-glass-fiber/PP specimens.

Nguyen, Ba Nghiep; Kunc, Vlastimil; Phelps, Jay; Tucker III, Charles L.; Bapanapalli, Satish K.

2008-09-01

154

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

Science.gov (United States)

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.

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

2012-09-01

155

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

Science.gov (United States)

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 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.

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

2014-05-01

156

Mold  

Science.gov (United States)

... through the NIEHS used ERMI to show that mold exposure during a critical window of development was associated ... recognition and management of health effects related to mold exposure and moisture indoors. 2 NAS (National Academy of ...

157

Development of Defects Free Stainless Steel Parts Using Powder Injection Molding  

Directory of Open Access Journals (Sweden)

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.

M.A. Omar

2013-01-01

158

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

Energy Technology Data Exchange (ETDEWEB)

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)

Gelin, J.C.; Barriere, Th. [Univ. de Franche-Compte, Lab. de Mecanique Appliquee R. Chaleat, Besancon (France); Liu, B. [Southwest Jiaotong Univ., Inst. of Engineering Science, Chengdu, Sichuan (China)

2000-07-01

159

Effect of rheological parameters on curing rate during NBR injection molding  

Science.gov (United States)

In this work, non-isothermal injection molding process for NBR rubber mixture considering Isayev-Deng curing kinetic model, generalized Newtonian model with Carreau-WLF viscosity was modeled by using finite element method in order to understand the effect of volume flow rate, index of non-Newtonian behavior and relaxation time on the temperature profile and curing rate. It was found that for specific geometry and processing conditions, increase in relaxation time or in the index of non-Newtonian behavior increases the curing rate due to viscous dissipation taking place at the flow domain walls.

Kyas, Kamil; Stanek, Michal; Manas, David; Skrobak, Adam

2013-04-01

160

FIBER LENGTH DISTRIBUTION MEASUREMENT FOR LONG GLASS AND CARBON FIBER REINFORCED INJECTION MOLDED THERMOPLASTICS  

Energy Technology Data Exchange (ETDEWEB)

Procedures for fiber length distribution (FLD) measurement of long fiber reinforced injection molded thermoplastics were refined for glass and carbon fibers. Techniques for sample selection, fiber separation, digitization and length measurement for both fiber types are described in detail. Quantitative FLD results are provided for glass and carbon reinforced polypropylene samples molded with a nominal original fiber length of 12.7 mm (1/2 in.) using equipment optimized for molding short fiber reinforced thermoplastics.

Kunc, Vlastimil [ORNL; Frame, Barbara J [ORNL; Nguyen, Ba N. [Pacific Northwest National Laboratory (PNNL); TuckerIII, Charles L. [University of Illinois, Urbana-Champaign; Velez-Garcia, Gregorio [Virginia Polytechnic Institute and State University

2007-01-01

 
 
 
 
161

The manufactoring of a twolayered injection mold by welding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The article presents the technology of deposit cladding different materials, using the injection molds for thermoplastic as a case study. The aim of the study is to surface weld to the working surface of the mold a different material with corresponding physical properties. Steel (1.1141) and a copper alloy were used as the base, onto which different materials were surface-welded. Tungsten inert gas (TIG) welding was employed to make molds inserts. An analysis of cross-sectioned specimens was ...

2011-01-01

162

Injection molding simulation to improve the efficiency and quality of metal molding designs. Kanagata no sekkei koritsu ka to hinshitsu kojo wo hakaru shashutsu seikei simulation  

Energy Technology Data Exchange (ETDEWEB)

In order to improve the efficiency and quality of metal molding designs, Sony Corp. has adopted an injection molding simulation system since the first half of 1980s. Since, however, molding materials are thermal fluids, which transit their phase from liquid into solid, and boundary conditions will be changed in the middle of their cycles, their analyzing works are very difficult. Therefore, softwares in this field are still on the way to be developed. Since this corporation has joined to the Cornell Injection Molding Program (CIMP) project in Cornell University, they have added improvements on their programs to be supplied, and have used them with their own programs developed additionally based on transformation processes. They have carried out minimizing of shape of boss root and examining holding pressure control by this simulation system. Since actually input works for CAD process have been carried out by hand now, it takes a time a little, though, they have also considered to make it easy by automating for applications of the full model. 4 refs., 7 figs.

Ito, Y. (Sony Corp., Tokyo (Japan))

1992-01-01

163

Simulao do processo de injeo de polipropileno isottico (iPP utilizando um modelo de cintica de cristalizao quiescente Simulation of injection molding process of isotactic polypropylene (iPP using a quiescent crystallization kinetics model  

Directory of Open Access Journals (Sweden)

Full Text Available Este trabalho concentrou-se na simulao das fases de preenchimento e resfriamento do processo de injeo do polipropileno isottico. Foi utilizado um modelo matemtico baseado nas equaes de conservao onde foi considerada a cintica de cristalizao quiescente como termo fonte na equao da energia. Os parmetros do modelo de cintica de cristalizao, assim como os do modelo de viscosidade, foram obtidos experimentalmente. Para a soluo das equaes governantes foi utilizado o mtodo dos volumes finitos. Como resultados foram obtidos os campos de temperatura, presso, velocidade, taxa de cisalhamento e cristalinidade em diferentes condies de processamento.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 equation. 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.

Marcos A d'vila

1997-12-01

164

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

165

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

Directory of Open Access Journals (Sweden)

Full Text Available Effects of injection temperature on thermal degradation and porosity of the bagasse/polypropylene injection molding composites were studied. Above 185 C, 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 increased the complete filling percentage. Mechanical properties decreased with increase of injection temperature from 165 C to 260 C. This was due to increase of porosity and fiber shortening. The calculated flexural modulus, which incorporated the effect of porosity and fiber length, agreed well with the experimental results. Composites with maleic acid anhydride grafted polypropylene (MAPP were also investigated. Flexural strength and impact strength were improved by 45% and 35%, respectively, by addition of 20wt% MAPP. In the MAPP composites, fiber breakages at their roots were observed in the fracture surface after an impact test, while pulled-off fibers were observed in those without MAPP.

Shinichi Shibata

2010-08-01

166

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 c...

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

2011-01-01

167

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 composi...

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

2010-01-01

168

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

169

Reduccin del Tiempo de Ciclo de Inyeccin de Termoplsticos con el uso de Moldes con Tratamiento Superficial por Nitruracin Cycle Time Reduction of Thermoplastic Injection using Nitriding Treatment Surface Molds  

Directory of Open Access Journals (Sweden)

Full Text Available Se presenta un estudio sobre la transferencia de calor en un molde, comparando los ensayos de inyeccin utilizando moldes con y sin tratamiento superficial de nitruracin. Simulaciones del proceso se realizaron con el uso de Asistencia Computacional a Ingeniera (CAE para determinar los parmetros iniciales que se aplicaron en los ensayos reales en moldes instrumentados de acero P20 (con y sin tratamientos, inyectados con el polmero poliestireno cristal. Los resultados indicaron una reduccin del tiempo de enfriamiento y del tiempo de proceso en el molde con el tratamiento, debido a una mejora en la conductividad trmica.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.

Emerson J Corazza

2012-01-01

170

Development and Design of Binder Systems for Titanium Metal Injection Molding: An Overview  

Science.gov (United States)

Titanium metal injection molding (Ti-MIM) has been practiced since the late 1980s. Logically, the Ti-MIM practice follows the similar processes developed for the antecedent materials such as stainless steel and ceramics. Although Ti-MIM is a favorite research topic today, the issue of convincing the designers to use Ti injection-molded parts still exists. This is mainly because of the concern about contamination which seems unavoidable during the Ti-MIM process. Much information about the binder formulation, powder requirements, debinding, and sintering is available in the literature. There are several powder vendors and feedstock suppliers. However, most of the binders in the feedstock are proprietarily protected. The disclosed information on the binders used for formulating powder feedstock is very limited, which in turn discourages their adoption by engineering designers. This overview intends to discuss some of major binder systems for Ti-MIM available in the literature. It serves to provide a guideline for the Ti-MIM practitioners to choose a suitable powder feedstock.

Wen, Guian; Cao, Peng; Gabbitas, Brian; Zhang, Deliang; Edmonds, Neil

2013-03-01

171

Mold  

Centers for Disease Control (CDC) Podcasts

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.

2011-05-02

172

Efeito do processamento em misturas de alumina/ligantes orgnicos usadas na moldagem por injeo em baixa presso Effect of processing variables in alumina/organic binders mixtures used in low-pressure injection molding  

Directory of Open Access Journals (Sweden)

Full Text Available A moldagem por injeo em baixa presso (MIBP uma tcnica que j vem sendo empregada na produo de peas cermicas com formas e geometrias complexas. A homogeneidade da mistura de ligantes orgnicos e ps cermicos um fator determinante que deve ser controlado para minimizar a formao de imperfeies no processamento de feedstocks para MIBP. Defeitos tpicos de processamento por MIBP, como bolhas de ar e aglomerados, geram gradientes de densidade nas misturas que, aps conformao, possuem poucas possibilidades de remoo. Essas imperfeies comprometem o desempenho dos produtos obtidos por essa tcnica. Este trabalho est focado na avaliao dessas heterogeneidades e como elas podem ser correlacionadas com a variao da densidade aparente e com o comportamento reolgico dessas misturas. Para tanto, aluminas submicromtricas, 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 auxlio de vcuo. Foi observada a presena de aglomerados existentes na alumina como recebida, possivelmente gerados durante a etapa de calcinao. Tambm foi observado que o tipo de misturador e a aplicao ou no de vcuo durante a etapa final do processamento tm grande influncia no tempo de mistura necessrio para reduzir a viscosidade do feedstock para a injeo.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.

P . A. Ourique

2013-03-01

173

Efeito do processamento em misturas de alumina/ligantes orgnicos usadas na moldagem por injeo em baixa presso / Effect of processing variables in alumina/organic binders mixtures used in low-pressure injection molding  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A moldagem por injeo em baixa presso (MIBP) uma tcnica que j vem sendo empregada na produo de peas cermicas com formas e geometrias complexas. A homogeneidade da mistura de ligantes orgnicos e ps cermicos um fator determinante que deve ser controlado para minimizar a formao de impe [...] rfeies no processamento de feedstocks para MIBP. Defeitos tpicos de processamento por MIBP, como bolhas de ar e aglomerados, geram gradientes de densidade nas misturas que, aps conformao, possuem poucas possibilidades de remoo. Essas imperfeies comprometem o desempenho dos produtos obtidos por essa tcnica. Este trabalho est focado na avaliao dessas heterogeneidades e como elas podem ser correlacionadas com a variao da densidade aparente e com o comportamento reolgico dessas misturas. Para tanto, aluminas submicromtricas, 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 auxlio de vcuo. Foi observada a presena de aglomerados existentes na alumina como recebida, possivelmente gerados durante a etapa de calcinao. Tambm foi observado que o tipo de misturador e a aplicao ou no de vcuo durante a etapa final do processamento tm grande influncia no tempo de mistura necessrio para reduzir a viscosidade do feedstock para a injeo. 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.

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

174

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)

2009-10-13

175

Design and development of an injection-molded demultiplexer for optical communication systems in the visible range.  

Science.gov (United States)

Optical simulation software based on the ray-tracing method offers easy and fast results in imaging optics. This method can also be applied in other fields of light propagation. For short distance communications, polymer optical fibers (POFs) are gradually gaining importance. This kind of fiber offers a larger core diameter, e.g., the step index POF features a core diameter of 980 ?m. Consequently, POFs have a large number of modes (>3 million modes) in the visible range, and ray tracing could be used to simulate the propagation of light. This simulation method is applicable not only for the fiber itself but also for the key components of a complete POF network, e.g., couplers or other key elements of the transmission line. In this paper a demultiplexer designed and developed by means of ray tracing is presented. Compared to the classical optical design, requirements for optimal design differ particularly with regard to minimizing the insertion loss (IL). The basis of the presented key element is a WDM device using a Rowland spectrometer setup. In this approach the input fiber carries multiple wavelengths, which will be divided into multiple output fibers that transmit only one wavelength. To adapt the basic setup to POF, the guidance of light in this element has to be changed fundamentally. Here, a monolithic approach is presented with a blazed grating using an aspheric mirror to minimize most of the aberrations. In the simulations the POF is represented by an area light source, while the grating is analyzed for different orders and the highest possible efficiency. In general, the element should be designed in a way that it can be produced with a mass production technology like injection molding in order to offer a reasonable price. However, designing the elements with regard to injection molding leads to some inherent challenges. The microstructure of an optical grating and the thick-walled 3D molded parts both result in high demands on the injection molding process. This also requires complex machining of the molding tool. Therefore, different experiments are done to optimize the process parameter, find the best molding material, and find a suitable machining method for the molding tool. The paper will describe the development of the demultiplexer by means of ray-tracing simulations step by step. Also, the process steps and the realized solutions for the injection molding are described. PMID:23842150

Hll, S; Haupt, M; Fischer, U H P

2013-06-20

176

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

Science.gov (United States)

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.

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

2014-05-01

177

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

Energy Technology Data Exchange (ETDEWEB)

Research highlights: > PP/CNFs and PP/TiO{sub 2} 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 TiO{sub 2} 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 TiO{sub 2} 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 TiO{sub 2}, 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 TiO{sub 2} nano particles.

Xie Lei, E-mail: Lei.Xie@tu-clausthal.de [Institute of Polymer Materials and Plastics Engineering, Technology University of Clausthal, Agricola str.6, 38678, Clausthal-Zellerfeld (Germany); Ziegmann, Gerhard [Institute of Polymer Materials and Plastics Engineering, Technology University of Clausthal, Agricola str.6, 38678, Clausthal-Zellerfeld (Germany)

2011-01-12

178

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.

2011-01-12

179

Micro Injection Molding of Thin Walled Geometries with Induction Heating System  

DEFF Research Database (Denmark)

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.

Menotti, Stefano; Hansen, Hans Nørgaard

2014-01-01

180

Hot mold casting process of ancient East India and Bangladesh  

Directory of Open Access Journals (Sweden)

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.

Barnali Mandal

2010-05-01

 
 
 
 
181

Investigation into the dynamic behavior of an injection molding non-return value  

Science.gov (United States)

The research presented in this dissertation describes experimentation and simulation to develop an understanding of the operation dynamics of injection molding non-return valves. The purpose of the valve is to shut the flow path between the injection screw and melt pool injected into the mold. The valve improves the variation in weight of the molded part. In addition, the valve provides a flow path during the plastication or recovery stage of the molding cycle. Experimental work has been developed to characterize the dynamic operating conditions of various commercially available non-return valves. Due to the transient nature of the non-return valve, benchmark experimental testing has been developed to understand the transient moving boundary during the flow of polymer melt in a rectangular channel. The non-return valve experiments have been simulated using a quasi-steady procedure and the simulation software FLUENT. The moving boundary polymer melt experiments have been simulated using the FLUENT software and viscoelastic software. In addition to this work, the flow of polymer melt through an axi-symmetric contraction has been simulated using the finite element method and the 3-mode Giesekus viscoelastic equation to progress the future development of viscoelastic code to simulate the injection molding non-return valve.

Zook, Christopher David

182

Aplikasi Rekayasa Mutu untuk Mengurangi Cacat pada Mesin Injection Molding  

Directory of Open Access Journals (Sweden)

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

Glenn Eko Yulianto

1999-01-01

183

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

Science.gov (United States)

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.

Blo, P.; Jttner, G.; Jacob, S.; Lser, C.; Michaelis, J.; Krajewsky, P.

2014-05-01

184

Comparison of several closure approximations for evaluating the thermoelastic properties of an injection molded short-fiber composite  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The accurate prediction of both the elastic properties and the thermal expansion coefficients is very important for the precise simulation of such processes as injection molding of short-fiber polymer-matrix composites. In this work, a two-step homogenization procedure is applied and compared with experimental values obtained on a polyarylamide/glass fiber composite for a broad range of temperatures. It is observed that the stiffness averaging version of the model surpasses the compliance ave...

Dray, Delphine; Gilormini, Pierre; Regnier, Gilles

2007-01-01

185

Development of the plasma sprayed plastics mold for injection molding. Plasma yoshaho ni yoru plastic kan'i kanagata no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a new mold developed for injection molding, which is characterized by the use of thermosetting resin for the core and cavity parts. For the purpose of improvement of durability, heat resistance, and finer surface quality, the core and cavity parts are coated with metal. For a series of experiments, in order to obtain high efficiency and high reliability of experiments, a parameter design method of quality engineering was applied. For the plasma spraying against epoxy resin, suppression of the effect of temperature on the resin was pointed out to be important. Since the heat conduction of mold developed is low, the molding cycle increased, but the molding quality was similar to that of the conventional mold. It was demonstrated that the total cost of new mold can be reduced compared with the mold for mass production. In conclusion, it was suggested that the present new mold can be applied to small batch production, new product development, and basic study on molding. 7 refs., 1 fig., 6 tabs.

Tanaka, H.; Soejima, T. (Industry Technology Center of Saga, Saga (Japan)); Ishida, H. (National Research Laboratory of Metrogy, Tsukuba (Japan)); Fukui, K. (Fukui Machine and Wood Mold Manufacturing, Saga (Japan))

1993-09-30

186

Improvements in sintered density and dimensional stability of powder injection-molded 316L compacts by adjusting the alloying compositions  

Energy Technology Data Exchange (ETDEWEB)

Powder injection molding is a process that provides advantages when making small parts with high density and complicated shapes. However, dimensional control of powder injection-molded stainless steel parts is difficult due to the presence of the liquid phase and the large amount of shrinkage that occurs during sintering. This study examines whether such a problem can be overcome through adjustments in the alloy composition and by making use of Thermo-Calc analysis. The results show that, with an increase in the molybdenum content up to the maximum limit according to existing specifications, a compact can be sintered to high densities without the presence of the liquid phase, while maintaining it in the dual-phase region of {gamma} + {delta}. In addition, dimensional control is improved. A slower heating rate is also found to be beneficial. These results are explained through dilatometric analysis and phase diagrams that are calculated using the Thermo-Calc program.

Shu, G.J. [Department of Materials Science and Engineering, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan (China); Hwang, K.S. [Department of Materials Science and Engineering, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan (China)]. E-mail: kshwang@ccms.ntu.edu.tw; Pan, Y.T. [Steel and Aluminum R and D Department, China Steel Corp., 1 Chung Kang Road, Kaohsiung 812, Taiwan (China)

2006-03-15

187

Microstructure and mechanical behavior of metal injection molded Ti-Nb binary alloys as biomedical material.  

Science.gov (United States)

The application of titanium (Ti) based biomedical materials which are widely used at present, such as commercially pure titanium (CP-Ti) and Ti-6Al-4V, are limited by the mismatch of Young's modulus between the implant and the bones, the high costs of products, and the difficulty of producing complex shapes of materials by conventional methods. Niobium (Nb) is a non-toxic element with strong ? stabilizing effect in Ti alloys, which makes Ti-Nb based alloys attractive for implant application. Metal injection molding (MIM) is a cost-efficient near-net shape process. Thus, it attracts growing interest for the processing of Ti and Ti alloys as biomaterial. In this investigation, metal injection molding was applied to the fabrication of a series of Ti-Nb binary alloys with niobium content ranging from 10wt% to 22wt%, and CP-Ti for comparison. Specimens were characterized by melt extraction, optical microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). Titanium carbide formation was observed in all the as-sintered Ti-Nb binary alloys but not in the as-sintered CP-Ti. Selected area electron diffraction (SAED) patterns revealed that the carbides are Ti2C. It was found that with increasing niobium content from 0% to 22%, the porosity increased from about 1.6% to 5.8%, and the carbide area fraction increased from 0% to about 1.8% in the as-sintered samples. The effects of niobium content, porosity and titanium carbides on mechanical properties have been discussed. The as-sintered Ti-Nb specimens exhibited an excellent combination of high tensile strength and low Young's modulus, but relatively low ductility. PMID:23994942

Zhao, Dapeng; Chang, Keke; Ebel, Thomas; Qian, Ma; Willumeit, Regine; Yan, Ming; Pyczak, Florian

2013-12-01

188

PP-polymer nanocomposites with improved mechanical properties using elongational flow devices at the injection molding compounder  

Science.gov (United States)

Numerous researches have been done in the field of improving PP by adding nanofillers. Consistently good scientific results and positive industrial feedback were reached; however, the industrial interest is still low due to the high technological and financial risks and too less benefit. Our experiments, using the worldwide unique Polymer NanoComposite Injection Molding Compounder (PNC-IMC) which combines the two processing steps of compounding and injection molding, showed an impressive increase of both mechanical and thermal properties, but more or less in the same range than in other publications. Thus we tried to improve the materials by using elongational flow generating devices for better intercalation and exfoliation of nanofillers in the polymer melt. This paper will give an overview on our first investigations, carried out on both a high pressure capillary rheometer (HPCR) and the injection molding machine (IMM) focusing on the mechanical properties. The PNCs were produced at the PNC-IMC with the 3in1 process. After the treatment in the HPCR the material was crushed, plates were prepared using a hydraulic vacuum press and tensile bars were milled, respectively tensile bars were produced with the IMM. The Young's modulus was successfully slightly improved. Thus future research will focus on both, the mechanism of improvement and the implementation of several of these devices into the PNC-IMC.

Battisti, M. G.; Friesenbichler, W.

2014-05-01

189

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

DEFF Research Database (Denmark)

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.

Tanzi, S.; Larsen, S.T.

2012-01-01

190

Injection molding of ceramics powder (CIM) with polyethylene glycol (PEG). Polyethylene glycol wo yuki binder ni mochiita ceramics no shashutsu seikei  

Energy Technology Data Exchange (ETDEWEB)

Authors have found of possibility of extractive dewaxing of injection molded materials with organic solvents possible to dewax in short time and examined to dewax the mixed powders of metal (SUS 316L) and ceramics (alumina and zirconia) in using polyolefine-peanut oil type binder applied with this technique. In this paper, a molding was extracted mainly with alcohol, which was injection molded in using zirconia and alumina blended powders with a binder consisting of ethylene-vinyl acetate copolymer and polyethyleneglycol. Consequently, it was found that low molecular weight polyethyleneglycol made rapid in the extraction speed but apt to reduce its mechanical strength. The extraction speed was found to be affected with the shape of moldings and extracting solvents. Furthermore, this process makes conventional heating extractions one about from one tenth to one fiftyth of them and was confirmed to be effective in ultra fine ceramics. 6 refs., 8 figs., 2 tabs.

Kankawa, Y.; Saito, K. (Kyoto Municipal Inst. of Industrial Research, Kyoto (Japan)); Kaneko, Y. (Ritsumeikan Univ., Kyoto (Japan). Faculty of Science and Engineering); Kasahara, N. (Mitsui Kinzoku, Tokyo (Japan))

1991-08-25

191

Microwaves energy in curing process of water glass molding sands  

Directory of Open Access Journals (Sweden)

Full Text Available This work presents the results of investigation of microwave heating on hardening process of water glass molding sands. Essential influence of this heating process on basic properties such as: compression, bending and tensile strength as well as permeability and abrasion resistance has been found. It has been proved, that all investigated sorts of sodium water glass with a module between 2.0 and 3.3 can be used as a binder of molding sands in microwave curing process. It has been found during analysis of research results of sands with 2.5 % water glass addition that they are practically the same as in case of identical molding sands dried for 120 minutes at the temperature of 110C, used for comparative purposes. Application of microwave curing of molding sands with water glass, however, guarantees reduction of hardening time (from 120 to 4 minutes as well as significant reduction of energy consumption. Attempts of two stage hardening of the investigated water glass molding sands have also been carried out, that is after an initial hardening during a classical CO2 process (identical sands have also been tested for comparison after CO2 blowing process and additional microwave heating. It has been found that application of this kind of treatment for curing sands with 2.5 % sodium water glass content and module from 2.0 up to 3.3 results in the improvement of properties in comparison to classical CO2 process.

Granat K.

2007-01-01

192

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 injec...

Soulestin, J.; Rajesh, J. J.; Lacrampe, M. F.; Krawczak, P.

2012-01-01

193

Powder Injection Molding - An innovative manufacturing method for He-cooled DEMO divertor components  

International Nuclear Information System (INIS)

At Karlsruhe Institute of Technology (KIT), a He-cooled divertor design for future fusion power plants has been developed. This concept is based on the use of modular cooling fingers made from tungsten and tungsten alloy, which are presently considered the most promising divertor materials to withstand the specific heat load of 10 MW/m2. Since a large number of the finger modules (n > 250,000) are needed for the whole reactor, developing a mass-oriented manufacturing method is indispensable. In this regard, an innovative manufacturing technology, Powder Injection Molding (PIM), has been adapted to W processing at KIT since a couple of years. This production method is deemed promising in view of large-scale production of tungsten parts with high near-net-shape precision, hence, offering an advantage of cost-saving process compared to conventional machining. The complete technological PIM process for tungsten materials and its application on manufacturing of real divertor components, including the design of a new PIM tool is outlined and, results of the examination of the finished product after heat-treatment are discussed. A binary tungsten powder feedstock with a solid load of 50 vol.% was developed and successfully tested in molding experiments. After design, simulation and manufacturing of a new PIM tool, real divertor parts are produced. After heat-treatment (pre-sintering and HIP) the successful finished samples showed a sintered density of approximately 99%, a hardness of 457 HV0.1, a grain size of approximately 5 ?m and a microstructure without cracks and porosity.

2011-10-01

194

Powder Injection Molding - An innovative manufacturing method for He-cooled DEMO divertor components  

Energy Technology Data Exchange (ETDEWEB)

At Karlsruhe Institute of Technology (KIT), a He-cooled divertor design for future fusion power plants has been developed. This concept is based on the use of modular cooling fingers made from tungsten and tungsten alloy, which are presently considered the most promising divertor materials to withstand the specific heat load of 10 MW/m{sup 2}. Since a large number of the finger modules (n > 250,000) are needed for the whole reactor, developing a mass-oriented manufacturing method is indispensable. In this regard, an innovative manufacturing technology, Powder Injection Molding (PIM), has been adapted to W processing at KIT since a couple of years. This production method is deemed promising in view of large-scale production of tungsten parts with high near-net-shape precision, hence, offering an advantage of cost-saving process compared to conventional machining. The complete technological PIM process for tungsten materials and its application on manufacturing of real divertor components, including the design of a new PIM tool is outlined and, results of the examination of the finished product after heat-treatment are discussed. A binary tungsten powder feedstock with a solid load of 50 vol.% was developed and successfully tested in molding experiments. After design, simulation and manufacturing of a new PIM tool, real divertor parts are produced. After heat-treatment (pre-sintering and HIP) the successful finished samples showed a sintered density of approximately 99%, a hardness of 457 HV0.1, a grain size of approximately 5 {mu}m and a microstructure without cracks and porosity.

Antusch, Steffen, E-mail: st.antusch@kit.edu [Karlsruhe Institute of Technology (KIT), Institute for Materials Research III, P.O. Box 3640, 76021 Karlsruhe (Germany); Norajitra, Prachai; Piotter, Volker; Ritzhaupt-Kleissl, Hans-Joachim; Spatafora, Luigi [Karlsruhe Institute of Technology (KIT), Institute for Materials Research III, P.O. Box 3640, 76021 Karlsruhe (Germany)

2011-10-15

195

Progress in simulating semi-flexible glass fiber orientation in an injection molded end-gated plaque  

Science.gov (United States)

The use of long fiber reinforced thermoplastics has gained increasing interest as a means to enhance a part's mechanical properties created through traditional melt processing techniques. Injection molding creates a complex microstructure to develop caused by flow field within the mold. Accurate predictions of fiber orientation can allow for mold design to be tailored to achieve a desired microstructure and mechanical properties. Simulations utilize the Bead-Rod orientation model adapted for concentrated suspensions to account for semi-flexible fibers by representing a fiber as two adjoined vectors that are free to rotate around the connecting point. This work uses orientation model parameters extracted from orientation data taken along the center plane at the transition between the gate and plaque. The entire mold cavity is simulated under non-isothermal conditions including the entry region to the plaque and the fountain flow behavior at the advancing front. Simulations of the semi-flexible model are compared to the Strain Reduction Factor (SRF) model developed for rigid fibers following the same simulation procedure. Predictions are compared to experimental data measured along and away from the plane of symmetry. Improvement in orientation predictions are obtained from the Bead-Rod model which greatly out performs the rigid fiber model away from the center plane.

Cieslinski, Mark J.; Meyer, Kevin J.; Baird, Donald G.

2014-05-01

196

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)

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, 50C, 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.)

Yalcin, Baris

197

The manufactoring of a twolayered injection mold by welding  

Directory of Open Access Journals (Sweden)

Full Text Available The article presents the technology of deposit cladding different materials, using the injection molds for thermoplastic as a case study. The aim of the study is to surface weld to the working surface of the mold a different material with corresponding physical properties. Steel (1.1141 and a copper alloy were used as the base, onto which different materials were surface-welded. Tungsten inert gas (TIG welding was employed to make molds inserts. An analysis of cross-sectioned specimens was made by optical microscopy, and chemical and hardness profiles were measured too. The thermal conductivity of base and cladded layer was also tested. Finally, a thermal fatigue test was employed to investigate the thermal fatigue properties of such surfaces.

A. Konik

2011-10-01

198

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

Science.gov (United States)

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

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

2014-06-01

199

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A evoluo da morfologia de fases em blendas no reativas e reativas de poliamida-6 com copolmero de acrilonitrila/EPDM/estireno (AES) em uma extrusora de rosca dupla co-rotacional foi investigada. A evoluo da morfologia de fases ao longo da extrusora de rosca dupla foi monitorada atravs da cole [...] ta de pequenas amostras em vlvulas no barril da extrusora e caracterizao por microscopia eletrnica de transmisso (MET). Foram utilizados como compatibilizantes reativos os copolmeros metacrilato de metila-co-anidrido maleico (MMA-MA) e metacrilato de metila-co-metacrilato de glicidila (MMA-GMA). Os grupos anidrido maleico e epxi nos copolmeros podem reagir com os grupos finais de cadeia da poliamida durante o processamento no estado fundido e melhorar a interao na interfase do sistema PA6/AES. A blenda PA6/AES no compatibilizada apresentou uma morfologia grosseira de fases onde a fase AES no est bem dispersa na matriz de PA6 devido falta de interaes adequadas entre os componentes da blenda. A adio do compatibilizante MMA-GMA no proporcionou boa disperso de fases e no melhorou as propriedades mecnicas da blenda, provavelmente porque as possveis reaes no sistema so lentas e podem no ocorrer na extrusora. Por outro lado, a blenda compatibilizada com o copolmero MMA-MA apresentou uma excelente resistncia ao impacto temperatura ambiente e uma diminuio na temperatura de transio dctil-frgil. As partculas de AES apresentam-se muito mais refinadas e sofrem uma reduo significativa em seu tamanho j no incio do processo de extruso. A morfologia observada nas amostras injetadas apresentou uma boa correlao com as propriedades mecnicas 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.

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

200

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

Directory of Open Access Journals (Sweden)

Full Text Available A evoluo da morfologia de fases em blendas no reativas e reativas de poliamida-6 com copolmero de acrilonitrila/EPDM/estireno (AES em uma extrusora de rosca dupla co-rotacional foi investigada. A evoluo da morfologia de fases ao longo da extrusora de rosca dupla foi monitorada atravs da coleta de pequenas amostras em vlvulas no barril da extrusora e caracterizao por microscopia eletrnica de transmisso (MET. Foram utilizados como compatibilizantes reativos os copolmeros metacrilato de metila-co-anidrido maleico (MMA-MA e metacrilato de metila-co-metacrilato de glicidila (MMA-GMA. Os grupos anidrido maleico e epxi nos copolmeros podem reagir com os grupos finais de cadeia da poliamida durante o processamento no estado fundido e melhorar a interao na interfase do sistema PA6/AES. A blenda PA6/AES no compatibilizada apresentou uma morfologia grosseira de fases onde a fase AES no est bem dispersa na matriz de PA6 devido falta de interaes adequadas entre os componentes da blenda. A adio do compatibilizante MMA-GMA no proporcionou boa disperso de fases e no melhorou as propriedades mecnicas da blenda, provavelmente porque as possveis reaes no sistema so lentas e podem no ocorrer na extrusora. Por outro lado, a blenda compatibilizada com o copolmero MMA-MA apresentou uma excelente resistncia ao impacto temperatura ambiente e uma diminuio na temperatura de transio dctil-frgil. As partculas de AES apresentam-se muito mais refinadas e sofrem uma reduo significativa em seu tamanho j no incio do processo de extruso. A morfologia observada nas amostras injetadas apresentou uma boa correlao com as propriedades mecnicas obtidas.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.

Adriane Bassani

2005-07-01

 
 
 
 
201

Development of step for light duty truck by using injection molding of long-fiber reinforced thermoplastics; Chosen`i kyoka jushi no shashutsu keisei ni yoru truck yo step no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

The new step for light duty truck was developed by injection molding of glass long-fiber reinforced polypropylene. Feature of the step is good surface appearance and no post processings, compared with the conventional one press molded with a glass fiber reinforced polypropylene sheet (Stampable sheet). 3 refs., 14 figs., 6 tabs.

Togo, A.; Yamamura, H.; Yamaguchi, M. [Mitsubishi Motor Corp., Tokyo (Japan); Yoshino, K. [Kawasaki Steel Corp. Tokyo (Japan)

1997-10-01

202

Research cooperation project on the development of easy injection molding control technology for engineering plastics; Engineering plastic no seikei joken kan`i settei gijutsu ni kansuru kenkyu kyoryoku jigyo seika hokokusho  

Energy Technology Data Exchange (ETDEWEB)

In order to enhance the industries which supply assembly parts to Japan`s assembly industries in Thailand, research cooperation project on the plastic parts production technology has started. For the research cooperation, the mold design is effectively conducted using simulation technique of CAE (computer aided engineering), and an international easy injection molding control system is made using the molding support software for injection molding machines. In FY 1996, actual situations of plastic parts and assembly industries in Thailand have been investigated through the cooperation with the counterpart of Thailand. Demand and supply of engineering plastics, receive and inspection of parts, and current circumstances of molding processing makers in Thailand have been grasped. Based on the results of this investigation, proposal of basic plan, time schedule, and delivery plan of molding machines and testing equipment have been discussed, to make the basic plan. 18 refs., 4 figs., 23 tabs.

NONE

1997-03-01

203

A X-ray study of ?-phase and molecular orientation in nucleated and non-nucleated injection molded polypropylene resins  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The development of ? and ?-phases and the molecular orientation of injection molded disks of two isotactic polypropylene (i-PP) resins were studied by wide angle X-ray diffraction (WAXD) and pole figures. A nucleated (NPP) and non-nucleated (HPP) polymers were analyzed. The main proposal of this art [...] icle was the comprehensive study of the interrelations between the processing conditions, phase contents and PP ?-phase molecular orientation of injection molded PP resins. In both resins, it was observed that the ?-phase was present in all regions along the thickness while the ?-phase was present mainly in the external layers, decreasing from the surface to the core; however this last phase was present in a very small amount in the NPP resin. For both polymers, the orientation of the macromolecules c-axis was higher along the flow direction (RD) than along the transverse direction (TD). The b-axis of the PP ?-phase molecules was oriented to the thickness direction (ND). The orientation of the c-axis along RD and b-axis along ND of the NPP samples was considerably higher than of the HPP samples, due to the NPP faster crystallization kinetics. For both polymers, the most influential processing parameters on the molecular orientation were the mold temperature and flow rate. The results indicate that, as the mold temperature increased, the characteristic molecular orientation of PP ?-phase, with c-axis along RD and b-axis along ND, decreased. With increase in the flow rate an increase of the c-axis molecular orientation of the samples along RD was observed.

Marcia Maria, Favaro; Marcia Cristina, Branciforti; Rosario Elida Suman, Bretas.

204

Studies on the injection molding of polyvinyl chloride: Analysis of viscous heating and degradation in simple geometries  

Science.gov (United States)

In injection molding processes, computer aided engineering (CAE) allows processors to evaluate different process parameters in order to achieve complete filling of a cavity and, in some cases, it predicts shrinkage and warpage. However, because commercial computational packages are used to design complex geometries, detail in the thickness direction is limited. Approximations in the thickness direction lead to the solution of a 2-D problem instead of a 3-D problem. These simplifications drastically reduce computational times and memory requirements. However, these approximations hinder the ability to predict thermal and/or mechanical degradation. The goal of this study was to determine the degree of degradation during PVC injection molding and to compare the results with a computational model. Instead of analyzing degradation in complex geometries, the computational analysis and injection molding trials were performed on typical sections found in complex geometries, such as flow in a tube, flow in a rectangular channel, and radial flow. This simplification reduces the flow problem to a 1-D problem and allows one to develop a computational model with a higher level of detail in the thickness direction, essential for the determination of degradation. Two different geometries were examined in this study: a spiral mold, in order to approximate the rectangular channel, and a center gated plate for the radial flow. Injection speed, melt temperature, and shot size were varied. Parts varying in degree of degradation, from no to severe degradation, were produced to determine possible transition points. Furthermore, two different PVC materials were used, low and high viscosity, M3800 and M4200, respectively (The Geon Company, Avon Lake, OH), to correlate the degree of degradation with the viscous heating observed during injection. It was found that a good agreement between experimental and computational results was obtained only if the reaction was assumed to be more thermally sensitive than found in literature. The results from this study show that, during injection, the activation energy for degradation was 65 kcal/mol, compared to 17--30 kcal/mol found in literature for quiescent systems.

Garcia, Jose Luis

2000-10-01

205

Moldagem por injeo 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)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A fabricao de moldes por tcnicas de prototipagem rpida, como a estereolitografia (SL), considerada uma importante tecnologia no auxlio ao desenvolvimento de produtos de plstico moldados por injeo. Embora esta tecnologia se mostre vantajosa, a vida til dos moldes pode ser bastante reduzida [...] em decorrncia, por exemplo, de forte adeso entre o polmero injetado e o material do molde SL. Neste trabalho investigado o uso da tcnica de recobrimento metlico com Ni-P por deposio electroless sobre moldes de injeo, fabricados por SL com a resina DSM SOMOS 7110. Foram comparados resultados de moldagem de PA6.6 em moldes fabricados com e sem recobrimento metlico evidenciando a possibilidade de utilizar a tcnica de metalizao como alternativa para a moldagem deste material em moldes SL, uma vez que a vida til 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.

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

206

Spray-formed Tooling for Injection Molding and Die Casting Applications  

Energy Technology Data Exchange (ETDEWEB)

Rapid Solidification Process (RSP) ToolingTM is a spray forming technology tailored for producing molds and dies. The approach combines rapid solidification processing and net-shape materials processing in a single step. The ability of the sprayed deposit to capture features of the tool pattern eliminates costly machining operations in conventional mold making and reduces turnaround time. Moreover, rapid solidification suppresses carbide precipitation and growth, allowing many ferritic tool steels to be artificially aged, an alternative to conventional heat treatment that offers unique benefits. Material properties and microstructure transformation during heat treatment of spray-formed H13 tool steel are described.

Mc Hugh, Kevin Matthew

2000-06-01

207

Use of commercial simulation software for analyzing the dynamics of an injection-molding clamp unit  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Today, the interest in integrated dynamic analysis of mechatronic systems increases. Different approaches are possible depending on the nature of the system, on the required complexity of the model, or simply on the tools available to the engineer. During this work, the aim was to implement specialized commercial simulation software packages and to combine them in order to simulate the dynamic behavior of mechatronic systems as for example an injection molding machine. The multi-body si...

Hostert, Claude

2006-01-01

208

Semi-automatic laboratory equipment for reactive injection molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Traditional melt processing techniques limit in shape and thickness the parts of fiber-reinforced thermoplastic composites. Producing of thermoplastic hybrid composites through melt intercalation often results in heterogeneous products due to micron-scale agglomerations with a negative effect on the mechanical properties. The in-situ polymerization processes to form the matrix in polymer composites have proved to be a good approach toward the resolution of these issues. In the present work we...

Pouzada, A. S.; Brito, A. M.; Oliveira, F. M.; Dencheva, Nadya Vasileva; Denchev, Z.; Lanceros-me?ndez, S.

2012-01-01

209

Three-dimensional ceramic molding process based on microstereolithography for the production of piezoelectric energy harvesters  

Science.gov (United States)

A three-dimensional (3-D) molding process using a master polymer mold produced by microstereolithography has been developed for the production of piezoelectric ceramic elements. In this method, ceramic slurry is injected into a 3-D polymer mold via a centrifugal casting process. The polymer master mold is thermally decomposed so that complex 3-D piezoelectric ceramic elements can be produced. As an example of 3-D piezoelectric ceramic elements, we produced a spiral piezoelectric element that can convert multidirectional loads into a voltage. It was confirmed that a prototype of the spiral piezoelectric element could generate a voltage by applying a load in both parallel and lateral directions in relation to the helical axis. The power output of 123 pW was obtained by applying the maximum load of 2.8N at 2 Hz along the helical axis. In addition, to improve the performance of power generation, we utilized a two-step sintering process to obtain dense piezoelectric elements. As a result, we obtained a sintering body with relative density of 92.8%. Piezoelectric constant d31 of the sintered body attained to -40.0 pC/N. Furthermore we analyzed the open-circuit voltage of the spiral piezoelectric element using COMSOL multiphysics. As a result, it was found that use of patterned electrodes according to the surface potential distribution of the spiral piezoelectric element had a potential to provide high output voltage that was 20 times larger than that of uniform electrodes.

Maruo, Shoji; Sugiyama, Kenji; Daicho, Yuya; Monri, Kensaku

2014-03-01

210

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

Directory of Open Access Journals (Sweden)

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.mol, a crystallinity degree of 60%, a glass transition temperature (Tg, at - 0.8 degreesC, and a melting temperature at 171 degreesC. 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 Tgs, at - 10.6 degreesC for the P(3HB matrix, and at - 62.9 degreesC 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.

Duarte Marcia Adriana Tomaz

2006-01-01

211

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.mol, 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 Tgs, 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.

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

212

Development, Strength and Functional Evaluation of Plastic Microneedle Array Fabricated by Injection Molding  

Science.gov (United States)

We hereby fabricated the microneedle arrays whose dimensions of 300 ?m in height, 100 and 150 ?m in diagonal lengths of bottom surface and with densities of 900 and 4,400 needles/ cm2 by injection molding. The resist patterns were pre-formed by three-dimensional fine manufacturing with movable resist during the exposure in LIGA process. Polylactic acid was used for microneedle arrays in consideration of the prospective medical use in transdermal methods and the like. Our study was to evaluate the material filling of the needle tips and dermal penetrability. The flexibility of the needle tips was also tested by the force added to the tips, and its result was compared with the analysis of flexibility by CAE; computer aided experiment. The resin filling did not reach to the deepest point of the Ni stamper, and the filling remained within the range of 12 to 17 ?m in diameter. However, the penetration rate on pig skin with the density of 900 needles / cm2 resulted in the range of 60 to 80%, and this result represented the satisfactory capability of dermal penetration in spite of the previously described needle tip dimensions of microneedle array. Closely resembling needle flexibility to its analysis proved that CAE analysis on the strength of microstructures was well effective.

Yoshimura, Chisato; Ishikawa, Hiroyuki; Furuta, Shinji; Aoki, Hikoharu; Sugiyama, Susumu

213

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

Science.gov (United States)

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

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

2014-02-28

214

Powder Injection Molding for mass production of He-cooled divertor parts  

Energy Technology Data Exchange (ETDEWEB)

A He-cooled divertor for future fusion power plants has been developed at KIT. Tungsten and tungsten alloys are presently considered the most promising materials for functional and structural divertor components. The advantages of tungsten materials lie, e.g. in the high melting point, and low activation, the disadvantages are high hardness and brittleness. The machinig of tungsten, e.g. milling, is very complex and cost-intensive. Powder Injection Molding (PIM) is a method for cost effective mass production of near-net-shape parts with high precision. The complete W-PIM process route is outlined and, results of product examination discussed. A binary tungsten powder feedstock with a grain size distribution in the range 0.7-1.7 {mu}m FSSS, and a solid load of 50 vol.% was developed. After heat treatment, the successfully finished samples showed promising results, i.e. 97.6% theoretical density, a grain size of approximately 5 {mu}m, and a hardness of 457 HV0.1.

Antusch, S., E-mail: st.antusch@kit.edu [Karlsruher Institut fuer Technologie (KIT), P.O. Box 3640, 76021 Karlsruhe (Germany); Norajitra, P.; Piotter, V.; Ritzhaupt-Kleissl, H.-J. [Karlsruher Institut fuer Technologie (KIT), P.O. Box 3640, 76021 Karlsruhe (Germany)

2011-10-01

215

Surface Hardening of Powder Injection Molded 316L Stainless Steels Through Low-Temperature Carburization  

Science.gov (United States)

The surface hardness of powder injection molded (PIM) 316L is generally low due to the inherited austenitic structure and large grains induced during high-temperature sintering. To increase the surface hardness and the wear resistance, low-temperature carburization (LTC) was applied to PIM 316L. With carburization at 773 K (500 C) for 24 hours, the resulting hardness at the surface increases from 160 to 810 HV due to the "colossal" supersaturation of interstitial carbon and M5C2 carbide, and the corrosion resistance is not deteriorated. The carburized depth is about 40 ?m, and the carbon content in this layer is about 3.25 wt pct or 13.5 at. pct, which causes lattice expansion of the austenite. When the carburization temperature increases to 823 K (550 C), or the carburization time increases to 72 hours, chromium carbides are observed and the corrosion resistance is impaired. One distinct advantage of applying LTC to PIM 316L is that no acid cleaning process is required, unlike for wrought counterparts, because of the clean surface of the sintered materials.

Cheng, Li-Hui; Hwang, Kuen-Shyang

2013-02-01

216

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)

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.

Weakley-Bollin, Shannon Christine

217

Freezing and Melting Characteristics of a Sand Mold Containing Water on the Freeze Mold Method Process Using Cold Airflow  

Science.gov (United States)

This paper reports the freezing and melting characteristics of a sand mold containing water on the freeze mold method. In the freeze mold method, water in the cast sand is frozen and the sand mold becomes hard without caking additives. In this study, the sand mold was cooled by cold airflow for using the freeze mold method in practical applications. In the experiments, the sand containing water was filled into a rectangular container, and then cold air of -30C was flowed into the container. After water in the sand was frozen, molten aluminum alloy of 900C was cast into the sand mold to make a test piece. The freezing and melting behavior of water in the sand was investigated experimentally under the various water amount conditions. As a result, it was found that water of 1 mass% in the sand was evaporated by the cold airflow in the freezing process. In the casting process, the movement of evaporation interface becomes slow as the water amount in the sand increases, on the other hand, the movement of melting interface is not influenced by the water amount so much.

Horibe, Akihiko; Inaba, Hideo; Haruki, Naoto; Miyagawa, Yasunori

218

The demolding of powder injection molded micro-structures: analysis, simulation and experiment  

Science.gov (United States)

This paper studies the demolding of an array of powder injection molded micro-structures based on a variotherm mold. The demolding of the micro-structures array was analyzed both theoretically and experimentally. Finite element method (FEM) software ABAQUS was used to analyze and simulate the demolding of an array of 24 24 (total of 576) micro-structures. It was found that there exists a 'critical temperature' at which the demolding force for the micro-structures array is a minimum. The stress distribution of the micro-structures and demolding force for the micro-structures during the course of demolding were analyzed for both demolding temperatures higher and lower than the critical temperature. Packing pressure and demolding temperature have an apparent impact on the demolding force. A series of demolding force measuring experiments at different packing pressures and demolding temperatures were conducted to verify the theoretical results.

Fu, G.; Tor, S. B.; Loh, N. H.; Tay, B. Y.; Hardt, D. E.

2008-07-01

219

The demolding of powder injection molded micro-structures: analysis, simulation and experiment  

International Nuclear Information System (INIS)

This paper studies the demolding of an array of powder injection molded micro-structures based on a variotherm mold. The demolding of the micro-structures array was analyzed both theoretically and experimentally. Finite element method (FEM) software ABAQUS was used to analyze and simulate the demolding of an array of 24 24 (total of 576) micro-structures. It was found that there exists a 'critical temperature' at which the demolding force for the micro-structures array is a minimum. The stress distribution of the micro-structures and demolding force for the micro-structures during the course of demolding were analyzed for both demolding temperatures higher and lower than the critical temperature. Packing pressure and demolding temperature have an apparent impact on the demolding force. A series of demolding force measuring experiments at different packing pressures and demolding temperatures were conducted to verify the theoretical results

2008-07-01

220

Influncia do desempenho trmico de moldes fabricados com compsito epxi/alumnio nas propriedades de pp moldado por injeo / Thermal behavior of epoxy/aluminum rapid tooling composite during injection molding of polypropylene  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O surgimento das tecnologias de prototipagem rpida (RP) e de ferramental rpido (RT) tem despertado interesse da indstria de moldes de injeo. O vazamento de termofixos com cargas metlicas possibilita a construo de moldes usando materiais compsitos, os quais apresentam maior resistncia que o [...] s utilizados por outras tcnicas RT. Neste trabalho foi estudado o comportamento trmico de moldes fabricados em epxi/alumnio durante a injeo de polipropileno atravs de avaliaes da estrutura e de propriedades mecnicas utilizando difrao de raio X e ensaios de dureza e de trao. Os corpos-de-prova injetados no molde em compsito epxi/alumnio apresentaram pequenas diferenas no grau de cristalinidade das superfcies analisadas e propriedades mecnicas semelhantes aos corpos-de-prova injetados em molde de ao. O estudo mostrou um razovel desempenho trmico do molde compsito durante a injeo de polipropileno evidenciando a viabilidade de utilizao destes moldes na produo de pequenas sries de prottipos e de produtos neste termoplstico. 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.

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

 
 
 
 
221

Microstructural study of duplex stainless steels obtained by powder injection molding  

Energy Technology Data Exchange (ETDEWEB)

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.

Sotomayor, M.E., E-mail: msotomay@ing.uc3m.es [Materials Science and Engineering Department, Carlos III University of Madrid, Avda. Universidad 30, 28911 Legans (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 Legans (Spain); Vrez, A., E-mail: alvar@ing.uc3m.es [Materials Science and Engineering Department, Carlos III University of Madrid, Avda. Universidad 30, 28911 Legans (Spain)

2014-03-15

222

Estudo de caso de pea moldada pelo processo de injeo-compresso para termoplsticos utilizando anlise computacional Study of injection-compression molded part using CAE analysis  

Directory of Open Access Journals (Sweden)

Full Text Available O processamento de termoplsticos atravs do processo de injeo representa o principal mtodo de fabricao de peas plsticas. Limitaes do processo de injeo convencional, principalmente quanto matria-prima e configurao e funcionamento das mquinas disponveis, tornam invivel a produo de produtos com grande rea projetada e pequena espessura, como janelas automotivas e alguns tipos de lentes. Paralelamente, o processo de injeo evolui continuamente e h uma srie de novas tecnologias geradas a partir do processo original, dentre elas o processo de injeo-compresso. No presente trabalho, utilizando anlise computacional, estudou-se a produo de lentes de policarbonato atravs de dois processos distintos: injeo convencional e processo de injeo-compresso. A seqncia de estudos envolveu basicamente os seguintes pontos: estudo do padro de preenchimento com conseqente otimizao do processo de injeo-compresso quanto formao de linha de emenda; estudo da janela de processo para ambos os casos e comparao de alguns parmetros principalmente tenso de cisalhamento e fora de fechamento, por se tratarem de fatores limitantes na produo de peas com grande rea projetada. Os resultados para o caso estudado comprovam grande vantagem na utilizao do processo de injeo-compresso.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 such 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.

Thyago M. Kiam

2007-03-01

223

Prediction of the Elastic-Plastic Stress/Strain Response for Injection-Molded Long-Fiber Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper proposes a model to predict the elastic-plastic response of injection-molded long-fiber thermoplastics (LFTs). The model accounts for elastic fibers embedded in a thermoplastic resin that exhibits the elastic-plastic behavior obeying the Ramberg-Osgood relation and J-2 deformation theory of plasticity. It also accounts for fiber length and orientation distributions in the composite formed by the injection-molding process. Fiber orientation was predicted using an anisotropic rotary diffusion model recently developed for LFTs. An incremental procedure using Eshelby's equivalent inclusion method and the Mori-Tanaka assumption is proposed to compute the overall stress increment resulting from an overall strain increment for an aligned-fiber composite that contains the same fiber volume fraction and length distribution as the actual composite. The incremental response of the latter is then obtained from the solution for the aligned-fiber composite by averaging over all fiber orientations. Failure during incremental loading is predicted using the Van Hattum-Bernado model. The model is validated against the experimental stress-strain results obtained for long-glass-fiber/polypropylene specimens.

Nguyen, Ba N. [Pacific Northwest National Laboratory (PNNL); Kunc, Vlastimil [ORNL; Phelps, Jay H [University of Illinois, Urbana-Champaign; TuckerIII, Charles L. [University of Illinois, Urbana-Champaign; Bapanapalli, Satish K [Pacific Northwest National Laboratory (PNNL)

2009-01-01

224

Prediction of the Elastic-Plastic Stress/Strain Response for Injection-Molded Long-Fiber Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper proposes a model to predict the elastic-plastic response of injection-molded long-fiber thermoplastics (LFTs). The model accounts for elastic fibers embedded in a thermoplastic resin that exhibits the elastic-plastic behavior obeying the Ramberg-Osgood relation and J-2 deformation theory of plasticity. It also accounts for fiber length and orientation distributions in the composite formed by the injection-molding process. Fiber orientation was predicted using the anisotropic rotary diffusion model recently developed by Phelps and Tucker for LFTs. An incremental procedure using the Eshelbys equivalent inclusion method and the Mori-Tanaka model is proposed to compute the overall stress increment resulting from an overall strain increment for an aligned fiber composite that contains the same fiber volume fraction and length distribution as the actual composite. The incremental response of the later is then obtained from the solution for the aligned fiber composite that is averaged over all possible fiber orientations using the orientation averaging method. Failure during incremental loading is predicted using the Van Hattum-Bernado model. The elastic-plastic and strength prediction model for LFTs was validated against the experimental stress-strain results obtained for long glass fiber/polypropylene specimens.

Nguyen, Ba Nghiep; Bapanapalli, Satish K.; Kunc, Vlastimil; Phelps, Jay; Tucker III, Charles L.

2009-01-26

225

Numerical simulation and experimental verification of melt front advancements in coinjection molding process  

Energy Technology Data Exchange (ETDEWEB)

Experimental studies of polymer melt flow in the mold filling stage of the coinjection molding process have been carried out using sequential injection of transparent and colored polystyrene resin. Simulations are also developed to predict the melt front advancements of both skin and core melts. A control volume/finite element method employed within each grid layer of the gapwise direction is applied to trace the melt front advancements for both skin and core materials. Numerical simulations show reasonably good consistency with experimental results in both skin and core material distribution. However, the simulation accuracy can be improved further if edge effect is taken into account using the shape factor as a geometrical correction.

Chen, S.C.; Hsu, K.F. [Chung Yuan Univ., Chung-Li (Taiwan, Province of China). Mechanical Engineering Dept.

1995-10-01

226

Miniature injection-molded optics for fiber-optic, in vivo confocal microscopy  

Science.gov (United States)

In collaboration with the Department of Biomedical Engineering at the University of Texas at Austin and the UT MD Anderson Cancer Center, a laser scanning fiber confocal reflectance microscope (FCRM) system has been designed and tested for in vivo detection of cervical and oral pre-cancers. This system along with specially developed diagnosis algorithms and techniques can achieve an unprecedented specificity and sensitivity for the diagnosis of pre-cancers in epithelial tissue. The FCRM imaging system consists of an NdYAG laser (1064 nm), scanning mirrors/optics, precision pinhole, detector, and an endoscopic probe (the objective). The objective is connected to the rest of the imaging system via a fiber bundle. The fiber bundle allows the rest of the system to be remotely positioned in a convenient location. Only the objective comes into contact with the patient. It is our intent that inexpensive mass-produced disposable endoscopic probes would be produced for large clinical trials. This paper touches on the general design process of developing a miniature, high numerical aperture, injection-molded (IM) objective. These IM optical designs are evaluated and modified based on manufacturing and application constraints. Based on these driving criteria, one specific optical design was chosen and a detailed tolerance analysis was conducted. The tolerance analysis was custom built to create a realistic statistical analysis for integrated IM lens elements that can be stacked one on top of another using micro-spheres resting in tiny circular grooves. These configurations allow each lens element to be rotated and possibly help compensate for predicted manufacturing errors. This research was supported by a grant from the National Institutes of Health (RO1 CA82880). Special thanks go to Applied Image Group/Optics for the numerous fabrication meetings concerning the miniature IM objective.

Chidley, Matthew D.; Liang, Chen; Descour, Michael R.; Sung, Kung-Bin; Richards-Kortum, Rebecca R.; Gillenwater, Ann

2002-12-01

227

Recycling process of casting molds applying to precision castings  

Directory of Open Access Journals (Sweden)

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.

M. Drajewicz

2012-12-01

228

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2004-01-01

229

FAI system for injection molding. ; Samples of flow analysis and warping analysis. Shashutsu seikei yo FAI system. ; Nagare to sori no kaiseki jirei  

Energy Technology Data Exchange (ETDEWEB)

CAE in injection molding is a technology that to predict the final quality of molded products by describing whole molding process histories on resins using computers. Currently, there is no such system to analyze whole molding process, though, it has been considered that metal mold flow analysis, holding pressure and cooling analysis have become a certain level which can be used in the actual works. In this report, some analysis examples to be used in The Furukawa Electric Co., Ltd. have been introduced. For flow analysis, FAI system has been developed based on FAN method. Since FAN method is rather easy to understand on its analysis principle, and is applicable to non-Newton fluids, it can be considered that it might be useful to understand flow analysis. Further, although many reasons for generating warpings such as unevenness of pressure, textile orientation, crystallization, etc. could be considered, some of main factors for reasons to be considered have been selected, and warping analysis have been approached. 3 refs., 10 figs.

Ishiwa, M.; Ueno, T. (The Furukawa Electric Co. Ltd., Tokyo (Japan))

1992-01-01

230

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

Directory of Open Access Journals (Sweden)

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.

Chen Changjun

2009-11-01

231

Time-Dependent Properties of Multimodal Polyoxymethylene Based Binder for Powder Injection Molding  

Science.gov (United States)

Powder injection molding (PIM) is one of the most versatile methods for the manufacturing of small complex shaped components from metal, ceramic or cemented carbide powders for the use in many applications. PIM consists of mixing the powder and a polymeric binder, injecting this mixture in a mold, debinding and then sintering. Catalytic debinding of polyoxymethylene (POM) is attractive since it shows high debinding rates and low risk of cracking. This work examines the possibility of using POM with bimodal molecular mass distribution as the main component of the binding agent by studying its time-dependent properties and comparing them to monomodal POM. Furthermore, possible optimization of the binder formulation was investigated by the addition of shorter polymeric chains (wax) to bimodal POM, as to create a multimodal material. It was observed that the magnitude of the complex viscosity for the commercial bimodal material was more than 2 times lower than for the chemically identical monomodal POM within the investigated frequency range and temperature. Viscosity values were observed to drop as the content of wax was increased, without compromising the binders mechanical properties in solid state. A new formulation of bimodal POM plus 8 wt.% of added wax provided the most appropriate results from investigated combinations. This work has shown how the addition of short polymeric chains in POM influences its time-dependent properties in solid and molten state, which can be an important tool for the optimization of binders designed to be used in PIM technology.

Gonzalez-Gutierrez, Joamin; Stringari, Gustavo Beulke; Zupancic, Barbara; Kubyshkina, Galina; Bernstorff, Bernd Von; Emri, Igor

232

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

1997-07-01

233

Physical properties of stainless steel slurry for metal injection molding; Kinzoku shashutsu seikeiyo stainless ko funmatsu slurry no kiso tokusei  

Energy Technology Data Exchange (ETDEWEB)

To obtain the sound green compacts in metal injection molding (MIM), it is very important to know the optimal injection molding conditions using the slurry flow analysis such as a Flow Analysis Network (FAN) method. The flow analysis method requires several basic parameters including the theological properties, e.g. viscosity, density and thermal conductivity of the slurry or green compacts. The physical properties of the MIM materials using a stainless steel SUS304 powder have been measured in this study, particularly for the temperature dependence of density, thermal conductivity and viscosity. The slurry viscosity was measured by the capillary test using the injection molding machine. From the experiments, the clear relations were obtained between the parameters and the temperature or share rate. Furthermore, from the flow analysis using the FAN method and the measured parameters, the detailed flow pattern was obtained in the wide range of temperatures during slurry filling in the mold cavity. The theological properties of slurry depending on the temperature were found to be very important factors in the numerical simulation for the optimization of injection molding conditions. 24 refs., 11 figs., 4 tabs.

Maeda, Y.; Ogawa, H.; Nomura, H. [Nagoya University, Nagoya (Japan)

1998-04-20

234

Rapid mold replication  

Energy Technology Data Exchange (ETDEWEB)

The desire to reduce tooling costs have driven manufacturers to investigate new manufacturing methods and materials. In the plastics injection molding industry replicating molds to meet production needs is time consuming (up to 6 months) and costly in terms of lost business. We have recently completed a feasibility study demonstrating the capability of high rate Electron Beam Physical Vapor Deposition (EBPVD) in producing mold inserts in days, not months. In the current practice a graphite mandrel, in the shape of the insert`s negative image, was exposed to a jet of metal vapor atoms emanating from an electron beam heated source of an aluminum-bronze alloy. The condensation rate of the metal atoms on the mandrel was sufficient to allow the deposit to grow at over 30 {mu}m/min or 1.2 mils per minute. The vaporization process continued for approximately 14 hours after which the mandrel and deposit were removed from the EBPVD vacuum chamber. The mandrel and condensate were easily separated resulting in a fully dense aluminum-bronze mold insert about 2.5 cm or one inch thick. This mold was subsequently cleaned and drilled for water cooling passages and mounted on a fixture for operation in an actual injection molding machine. Results of the mold`s operation were extremely successful showing great promise for this technique. This paper describes the EBPVD feasibility demonstration in more detail and discusses future development work needed to bring this technique into practice.

Heestand, G.M.; Beeler, R.G. Jr.; Brown, D.L. [and others

1995-06-01

235

Novel binder system based on paraffin-wax for low-pressure injection molding of metal-ceramic powder mixtures  

Energy Technology Data Exchange (ETDEWEB)

Powder injection molding is already well known as one of the most promising techniques for the manufacture of smaller series of complex-shaped and customer-designed ceramic matrix composites parts. Compared with high-pressure injection molding, the low-pressure technique (LPIM) requires far less operational pressure and temperature and, therefore, less capital investment. A key to the successful application of the LPIM technology is the selection of a binder system enabling high solid loading at a sufficiently low viscosity together with a suitable debinding technique. In this communication, a novel binder system originally developed for LPIM of Al{sub 2}O{sub 3} is presented. (orig.)

Leverkoehne, M.; Coronel-Hernandez, J.; Janssen, R.; Claussen, N. [Technische Univ. Hamburg-Harburg, Hamburg (Germany). Advanced Ceramics Group; Dirscherl, R. [Nabaltec GmbH, Schwandorf (Germany); Gorlov, I. [Vopelius Chemie GmbH, Moscow (Russian Federation)

2001-12-01

236

Inner defect evaluation of metal injection molded specimens; Kinzoku funmatsu shashutsu seikeitai no naibu kekkan hyoka  

Energy Technology Data Exchange (ETDEWEB)

Discussions were given on the effect of injecting condition for metal powder injection molding on inner defects. Macroscopically, the progress of inner defects on cracks is affected by the state of temperature distribution in the whole green body when the binder solidifies and shrinks. These effects vary by injecting conditions such as injection velocity. Gate position also gives an effect. Microscopically, since the metal powder and binder are distributed non-uniformly, tensile stress concentrates locally, thus their position becomes a starting point of crack-like inner defect. These cracks propagate through the binder before solidification, and stop as a result of the solidification of the binder. Correlation is found between the state of compound on the surface and the inner defects, and cracks were developed at positions where the surface compound condition changes if defects exist internally. Therefore, although it may difficult to predict exactly existence of inner defects from the surface condition, it is possible to estimate positions of crack generation in the case where defects exist. 5 refs., 10 figs.

Hirose, N. [Tokyo Metropolitan Industrial Technology Research Institute, Tokyo (Japan); Kankawa, Y. [Kyoto Municipal Research Inst. of Industrial Research, Kyoto (Japan); Asami, J. [Tokyo Metropolitan Jonan Industrial Promotion Center, Tokyo (Japan)

1997-09-15

237

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

DEFF Research Database (Denmark)

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.

?stergaard, Peter Friis; Matteucci, Marco

2013-01-01

238

Fabrication of a polyurethane acrylate/polyimide-based polymer mold for a hot embossing process.  

Science.gov (United States)

A high-thermal-resistance polymer-based flexible imprint mold was developed to be used in a hot embossing process. This mold was readily replicated in a UV curing imprint process and can be used as a mold for hot embossing and thermally curing imprint processes. The nano-sized pattern of this mold was not degraded by soaking at 350 degrees C for 10 min and the pattern fidelity was maintained after 10 separate cyclic heating tests between 0 degrees C and 350 degrees C. The substrate of this flexible mold was PI film, and a UV-cured polyurethane acrylate (PUA) layer was used to form the nano-scale patterns. The durability of this polymeric mold was tested by repetitive hot embossing processes. Nano-scale patterns of the mold were readily transferred to a PMMA layer coated onto a Si substrate by hot embossing lithography at 180 degrees C. After 10 cycles of hot embossing processes, no damage or degradation was observed in the flexible polymer mold. Using this polymer mold, patterns as small as 50 nm were successfully transferred to a Si substrate. Due to the flexibility of the polymer mold, nano-scale patterns were successfully transferred to a non-flat acryl substrate by hot embossing lithography. PMID:22849136

Kim, Kang-In; Han, Kang-Soo; Yang, Ki-Yeon; Kim, Hyeong-Seok; Lee, Heon

2012-04-01

239

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

DEFF Research Database (Denmark)

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.

Andresen, Kristian; Hansen, Morten

2010-01-01

240

Biodegradability of injection molded bioplastic pots containing polylactic acid and poultry feather fiber.  

Science.gov (United States)

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

Ahn, H K; Huda, M S; Smith, M C; Mulbry, W; Schmidt, W F; Reeves, J B

2011-04-01

 
 
 
 
241

Injection-molded Sm-Fe-N anisotropic magnets using unsaturated polyester resin  

Energy Technology Data Exchange (ETDEWEB)

New injection-molding technology has been developed using an unsaturated polyester (UP) resin in order to produce bonded Sm-Fe-N anisotropic magnets. Sheet magnets of 50 mm x 20 mm x 0.36 mm are successfully made within a cycle time of 90 s. Magnetic properties obtained are almost the same as those obtained in column magnets of {phi}10 mm x 7 mm. Typical data of magnetic properties are as follows: B {sub r} = 0.72 T, H {sub CJ} = 796 kA/m and (BH){sub max} 94.7 kJ/m{sup 3}. The density is 4.79 Mg/m{sup 3}. The degree of orientation of (0 0 6) is 5.31 calculated using the Wilson formula from X-ray diffraction result. Ring magnets of 7.4 mm x 3.2 mm x 0.3 mm are easily made from sheet magnets.

Ohmori, K. [Sumitomo Metal Mining Co. Ltd., 3-18-5 Nakakokubun, Ichikawa, Chiba 272-8588 (Japan)]. E-mail: k_omori@adch.smm.co.jp; Hayashi, S. [Sumitomo Metal Mining Co. Ltd., 3-18-5 Nakakokubun, Ichikawa, Chiba 272-8588 (Japan); Yoshizawa, S. [Sumitomo Metal Mining Co. Ltd., 3-18-5 Nakakokubun, Ichikawa, Chiba 272-8588 (Japan)

2006-02-09

242

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...

243

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)

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.

Fatih Mengeloglu,

2012-06-01

244

Miniature Fabry-Perot pressure sensor created by using UV-molding process with an optical fiber based mold.  

Science.gov (United States)

We present a miniature Fabry-Perot pressure sensor fabricated at the tip of an optical fiber with a pre-written Bragg grating by using UV-molding polymer process. The mold is constructed by integrating an optical fiber of 80 ?m diameter with a zirconia ferrule. The optical fiber based mold makes it possible to use optical aligning method to monitor the coupled intensity between the mold-side and replica-side fibers, rendering a maskless alignment process with a submicrometer accuracy. A polymer-metal composite thin diaphragm is employed as the pressure transducer. The overall sensor size is around 200 ?m in diameter. Experimental study shows that the sensor exhibits a good linearity over a pressure range of 1.9-7.9 psi, with a sensitivity of 0.0106 ?m/psi. The fiber Bragg grating is exploited for simultaneous temperature measurements or compensation for temperature effects in pressure readings. The sensor is expected to benefit many fronts that require miniature and inexpensive sensors for reliable pressure measurement, especially biomedical applications. PMID:22714519

Bae, H; Yu, M

2012-06-18

245

Dielectric elastomer actuators fabricated using a micro-molding process  

Science.gov (United States)

All-polymer dielectric elastomer actuators have been manufactured using a micro-molding fabrication process. The actuators are multilayer beams made of three conductive and two dielectric elastomer layers. By applying an electrical potential between two of the neighboring conductive electrodes, a stress is generated, which leads to an asymmetric axial strain and, therefore, bending. Bidirectional actuation is achieved by changing the pair of electrodes across which the potential is applied. A 100 ?m wide, 40 ?m thick, and 1000 ?m long actuator demonstrated tip displacement as high as 318 ?m at 1.1 kV with an electrical power consumption of 10 ?W. Experimental results validate a two-dimensional ANSYS model that is also used to explore the effects of further decreasing layer thickness and relative electrode thickness on DEA performance.

Gerratt, Aaron P.; Balakrisnan, Bavani; Penskiy, Ivan; Bergbreiter, Sarah

2014-05-01

246

Granular modeling for dense powder-binder compound flow in metal injection molding  

Energy Technology Data Exchange (ETDEWEB)

To elucidate the fundamental behavior and promote further improvement of flowability and formability of the compound medium with the thermoplastic polymer and dense metallic powder in the metal injection molding, a new granular model is proposed and effectiveness of the model is verified by simulation. Each element in this model is constituted by combining a metal powder core with a binder shell surrounding it. Both elasticity and viscosity for the powder-binder compound are expressed by mechanical relations among these particles with binders. To deal with the reciprocal change between temperature and physical properties when the powder-binder compound is injected into cooled close dies, thermo-mechanical coupling method with the mapping/remapping procedure is introduced to the granular model. By using these methods, several examples such as capillary viscometer flow, vertical channel flow, bended channel flow, gate flow, and cavity filling flow are numerically simulated. These results demonstrate validity of the model, in comparison with experimental results. 19 refs., 26 figs., 5 tabs.

Iwai, T.; Aizawa, T.; Kihara, J. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering

1994-09-30

247

Phenolic Molding Compounds  

Science.gov (United States)

Phenolic Molding Compounds continue to exhibit well balanced properties such as heat resistance, chemical resistance, dimensional stability, and creep resistance. They are widely applied in electrical, appliance, small engine, commutator, and automotive applications. As the focus of the automotive industry is weight reduction for greater fuel efficiency, phenolic molding compounds become appealing alternatives to metals. Current market volumes and trends, formulation components and its impact on properties, and a review of common manufacturing methods are presented. Molding processes as well as unique advanced techniques such as high temperature molding, live sprue, and injection/compression technique provide additional benefits in improving the performance characterisitics of phenolic molding compounds. Of special interest are descriptions of some of the latest innovations in automotive components, such as the phenolic intake manifold and valve block for dual clutch transmissions. The chapter also characterizes the most recent developments in new materials, including long glass phenolic molding compounds and carbon fiber reinforced phenolic molding compounds exhibiting a 10-20-fold increase in Charpy impact strength when compared to short fiber filled materials. The role of fatigue testing and fatigue fracture behavior presents some insight into long-term reliability and durability of glass-filled phenolic molding compounds. A section on new technology outlines the important factors to consider in modeling phenolic parts by finite element analysis and flow simulation.

Koizumi, Koji; Charles, Ted; de Keyser, Hendrik

248

Metal injection molding of Ti-Mo-Al mixed powder. Ti-Mo-Al kongofun no idashi seikei  

Energy Technology Data Exchange (ETDEWEB)

Metal injection molding of Ti-15Mo-3Al alloys was studied by use of the Ti-Mo-Al compound composed of Ti powder with an average diameter of 38 [mu]m, Mo powder of 1.24 [mu]m, TiAl alloy powder of 9.4 [mu]m and two types of wax-polymer binders. Since oxidation of the compound in the air was depressed by using TiAl alloy powder substituted for Al powder, kneading, molding and debinding of the compound were successfully conducted in the air. The relative density of the sintered compacts approached as high as 97% or more through debinding at 210[degree]C in the air and at 500-550[degree]C in vacuum, and sintering at 1296[degree]C in vacuum for 3 hours. A large amount of precipitated Ti oxide particles were observed in sintered microstructures of die pressed compacts, however, in the case of injection molded compacts, since residual C derived from the binder reduced Ti oxides, TiC particles were observed instead of Ti oxide ones. Such precipitated TiC probably enhanced densification of the injection molded sintered compacts depressing crystal grain growth in them. 2 refs., 7 figs.

Takekawa, J. (Ishinomaki Senshu University, Miyagi (Japan))

1994-03-13

249

Bi-composite sandwich moldings : processing, mechanical performance and bioactive behaviour  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two composite systems composed of high-density polyethylene (HDPE) filled with hydroxyapatite (HA) and carbon fiber (C fiber) were compounded in a co-rotating twin screw extruder and subsequently molded in a two component injection molding machine in order to produce test bars with a sandwich-like morphology. These moldings are based on a HDPE/HA composite outer layer and a HDPE/C fiber composite core. The mechanical performance of the obtained specimens was assessed by tensile and impact tes...

2003-01-01

250

Metal injection molding as enabling technology for the production of metal prosthesis components: electrochemical and in vitro characterization.  

Science.gov (United States)

Industrial manufacturing of prosthesis components could take significant advantage by the introduction of new, cost-effective manufacturing technologies with near net-shape capabilities, which have been developed during the last years to fulfill the needs of different technological sectors. Among them, metal injection molding (MIM) appears particularly promising for the production of orthopedic arthroplasty components with significant cost saving. These new manufacturing technologies, which have been developed, however, strongly affect the chemicophysical structure of processed materials and their resulting properties. In order to investigate this relationship, here we evaluated the effects on electrochemical properties, ion release, and in vitro response of medical grade CoCrMo alloy processed via MIM compared to conventional processes. MIM of the CoCrMo alloy resulted in coarser polygonal grains, with largely varying sizes; however, these microstructural differences between MIM and forged/cast CoCrMo alloys showed a negligible effect on electrochemical properties. Passive current densities values observed were 0.49 A cm(-2) for MIM specimens and 0.51 A cm(-2) for forged CoCrMo specimens, with slightly lower transpassive potential in the MIM case; open circuit potential and Rp stationary values showed no significant differences. Moreover, in vitro biocompatibility tests resulted in cell viability levels not significantly different for MIM and conventionally processed alloys. Although preliminary, these results support the potential of MIM technology for the production of CoCrMo components of implantable devices. PMID:23661502

Melli, Virginia; Rondelli, Gianni; Sandrini, Enrico; Altomare, Lina; Bolelli, Giovanni; Bonferroni, Benedetta; Lusvarghi, Luca; Cigada, Alberto; De Nardo, Luigi

2013-10-01

251

Fabrication and characterization of injection molded poly ({epsilon}-caprolactone) and poly ({epsilon}-caprolactone)/hydroxyapatite scaffolds for tissue engineering  

Energy Technology Data Exchange (ETDEWEB)

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.

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

252

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-ThienTanner (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

2011-12-01

253

Thermal shock behavior of tungsten based alloys manufactured via powder injection molding  

Energy Technology Data Exchange (ETDEWEB)

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.

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

254

Trial production of titanium orthodontic brackets fabricated by metal injection molding (MIM) with sintering.  

Science.gov (United States)

Safety and esthetics are two indispensable factors to consider when fabricating orthodontic brackets. However, these factors are not easily achieved when conventional techniques (including forging and casting) are used in the mass production of titanium brackets, albeit the brackets exhibit excellent biocompatibility. In the present study, orthodontic brackets were manufactured by metal powder injection molding with sintering. Brackets with three different base designs were made and subjected to compression shear tests for evaluation of their bonding strength to enamel substrate. The shapes given to the dimple of the base were spherical, oval, and grooved. The maximum shear forces for each type were 11.1 kgf, 7.6 kgf, and 18.5 kgf, respectively. The bonding strengths of the titanium bracket were equivalent to those obtained with conventional stainless steel brackets. Moreover, uniform distribution of Vickers hardness values (average, 240 +/- 40 Hv) measured at three locations indicated that the titanium bracket was uniformly sintered. Accordingly, titanium brackets thus fabricated exhibit a potential for clinical application. PMID:8876601

Deguchi, T; Ito, M; Obata, A; Koh, Y; Yamagishi, T; Oshida, Y

1996-07-01

255

Constante de mola de molas cermicas injetadas a baixa presso Spring constant of low-pressure injection molded ceramic springs  

Directory of Open Access Journals (Sweden)

Full Text Available A dificuldade de usinagem de peas cermicas j sinterizadas muito grande, principalmente devido dureza e fragilidade destes materiais, o que implica em altos custos de produo. Por isso, grandes esforos tem sido feitos no sentido de melhorar os processos de conformao a verde existentes, ou criar novos processos que permitam a obteno de peas cada vez mais prximas do formato final desejado. Produzir peas cermicas com formatos complexos, livres de defeitos, uma tarefa que implica em grandes dificuldades. Molas cermicas possuem formatos extremamente difceis de serem moldados e, conseqentemente, atualmente so produzidas comercialmente molas cermicas pelo processo de usinagem, geralmente a um custo elevado. Uma alternativa para a produo de molas cermicas a moldagem por injeo em baixa presso. Para o desenvolvimento de molas cermicas para aplicaes tecnolgicas, necessrio, alm de obter peas ntegras e livres de defeitos, aferir algumas de suas propriedades, como a constante de mola. Uma vez que estas molas encontram aplicao em altas temperaturas, torna-se imprescindvel realizar a medida da resistncia imposta pela mola deformao elstica em diferentes temperaturas. Para tanto, este trabalho propem a montagem de um sistema para a medio da constante de mola de molas cermicas injetadas a baixa presso, tanto temperatura ambiente como em altas temperaturas, usando o mtodo dinmico da excitao por impulso para medir a frequncia de vibrao da mola suspensa no interior de um forno. Para ilustrar a aplicao desta tcnica so apresentados resultados obtidos para uma mola helicoidal de alumina, da temperatura ambiente at 1100 C.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 C to illustrate the application of this technique.

R. A. Barbieri

2011-12-01

256

Constante de mola de molas cermicas injetadas a baixa presso / Spring constant of low-pressure injection molded ceramic springs  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A dificuldade de usinagem de peas cermicas j sinterizadas muito grande, principalmente devido dureza e fragilidade destes materiais, o que implica em altos custos de produo. Por isso, grandes esforos tem sido feitos no sentido de melhorar os processos de conformao a verde existentes, ou [...] criar novos processos que permitam a obteno de peas cada vez mais prximas do formato final desejado. Produzir peas cermicas com formatos complexos, livres de defeitos, uma tarefa que implica em grandes dificuldades. Molas cermicas possuem formatos extremamente difceis de serem moldados e, conseqentemente, atualmente so produzidas comercialmente molas cermicas pelo processo de usinagem, geralmente a um custo elevado. Uma alternativa para a produo de molas cermicas a moldagem por injeo em baixa presso. Para o desenvolvimento de molas cermicas para aplicaes tecnolgicas, necessrio, alm de obter peas ntegras e livres de defeitos, aferir algumas de suas propriedades, como a constante de mola. Uma vez que estas molas encontram aplicao em altas temperaturas, torna-se imprescindvel realizar a medida da resistncia imposta pela mola deformao elstica em diferentes temperaturas. Para tanto, este trabalho propem a montagem de um sistema para a medio da constante de mola de molas cermicas injetadas a baixa presso, tanto temperatura ambiente como em altas temperaturas, usando o mtodo dinmico da excitao por impulso para medir a frequncia de vibrao da mola suspensa no interior de um forno. Para ilustrar a aplicao desta tcnica so apresentados resultados obtidos para uma mola helicoidal de alumina, da temperatura ambiente at 1100 C. 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 C to illustrate the application of this technique.

Barbieri, R. A.; Zorzi, J. E..

257

Optical injection processes in semiconductors  

Science.gov (United States)

We present a theoretical review and band structure calculations of optical injection processes in semiconductors. The study of these processes in bulk materials provides a benchmark and reference for their future applications in quantum wells and other nanostructures. We discuss the injection and coherent control of charge, spin, current, and spin current in bulk GaAs using a full-Brillouin zone, 30-band kp model in the independent-particle approximation. Carrier injection and optical orientation are presented for one- and two-photon absorption, including anisotropy and linear-circular dichroism in the two-photon absorption coefficients. Quantum-mechanical interference effects are considered in carrier, spin, current, and spin current excitation using coherent optical field components at frequencies ? and 2?. We calculate the spectral dependence of these all-optical effects for excitation energy in the range from 0 eV to 4 eV. Significant spin and spin current injection is found for transitions away from the Brillouin-zone center at the E1 resonance.

Rioux, J.; Sipe, J. E.

2012-08-01

258

Forming of Mo and Ti silicides by means of injection molding; Formgebung von Molybdaen- und Titansiliziden ueber das Pulvermetallformspritzen  

Energy Technology Data Exchange (ETDEWEB)

The report describes the processing of TiSi{sub 2}, MoSi{sub 2} and Ti{sub 5}Si{sub 3} by means of metal injection molding (MIM). First, the sintering activities of the three materials were investigated. After this, the viscosities of different mixtures of organic binder and powders of the three materials were determined, and in the final stage, components were produced by injection molding, the binder was removed, and the components were sintered. TiSi{sub 2} in powder form could be sintered to more than 95% of its theoretical density after 4 h at 1386 C. Metallographic analyses proved leaktightness of the component at this density. In the case of Ti{sub 5}Si{sub 3}, it was found that this material requires very long sintering times and high sintering temperatures for sintering to about 94% of its theoretical density. Metallographic analyses showed that only about 90% of the theoretical density was reached. MoSi{sub 2} in powder form could be sintered to only 90% of its theoretical density. With components made of pressed powder with grain sizes around 10.2{mu}, sintering times of about 8h at 1750 in vacuum resulted in densities higher than 93 . Metallographic samples were found to have pores. (orig./MM) [Deutsch] In dieser Arbeit wurde die Verarbeitung von TiSi{sub 2}, MoSi{sub 2} und Ti{sub 5}Si{sub 3} durch das Metallformspritzverfahren (MIM) dargestellt. Hierzu wurde zunaechst die Sinteraktivitaet der drei Werkstoff untersucht. Anschliessend wurde die Fliessfaehigkeit von verschiedenen Gemischen aus organischem Binder und Pulver der drei Werkstoffe ermittelt und dann Bauteile auf einer Spritzgussmaschine hergestellt, entbindert und gesintert. Das TiSi{sub 2} liess ssich als Pulverschuettung nach 4 h bei 1386 C auf ueber 95% der theoretischen Dichte sintern. Die metallographischen Untersuchungen zeigten, dass das Bauteil bei dieser Dichte dicht ist. Bei der Untersuchung von Ti{sub 5}Si{sub 3} zeigt sich, dass sich dieser Werkstoff nur bei sehr langen Sinterzeiten und hohen Sintertemperaturen auf Dichten um 94% der theoretischen Dichte sintern laesst. Die metallographischen Schliffe zeigten aber, dass nur eine Dichte von etwa 90% erreicht wurde. Das MoSi{sub 2} liess sich als Pulverschuettung nur bis auf 90% der theoretischen Dichte sintern. Sinterzeiten um 8 h bei 1750 C im Vakuum fuehrten mit Presslingen aus gemahlenem Pulver um 10,2 {mu}m mittlerer Korndurchmesser zu Dichten ueber 93%. Die Proben hatten in den Schliffen noch reichlich Poren. (orig./MM)

Fuest, C.

1994-10-01

259

Brightness field distributions of microlens arrays using micro molding.  

Science.gov (United States)

This study describes the brightness field distributions of microlens arrays fabricated by micro injection molding (?IM) and micro injection-compression molding (?ICM). The process for fabricating microlens arrays used room-temperature imprint lithography, photoresist reflow, electroforming, ?IM, ?ICM, and optical properties measurement. Analytical results indicate that the brightness field distribution of the molded microlens arrays generated by ?ICM is better than those made using ?IM. Our results further demonstrate that mold temperature is the most important processing parameter for brightness field distribution of molded microlens arrays made by ?IM or ?ICM. PMID:21196966

Cheng, Hsin-Chung; Huang, Chiung-Fang; Lin, Yi; Shen, Yung-Kang

2010-12-20

260

Fabrication of Bonding-Type Hollow Microneedle Array by Injection Molding and Evaluation of its Puncture Characteristics  

Science.gov (United States)

A microneedle array which consists from small needles compared to a conventional metal injection needle is expected as a low invasive transdermal medical treatment device, and many fabrication approach have been conducted. In this study, we fabricated plastic hollow microneedle array by a fabrication method based on the combination of injection molding, bonding and assembly techniques. To evaluate puncture characteristics of the fabricated needle, we measured a puncture force to silicone rubber by experimental equipment using loadcell and automatic stage. Furthermore, we propose and demonstrate a new method to measure actual punctured depth from punctured trace on the needle surface modified by O2 plasma treatment.

Ogai, Noriyuki; Sugimura, Ryo; Tamaru, Takuya; Takiguchi, Yoshihiro

 
 
 
 
261

Modeling of Initial Mold Filling in Uphill Teeming Process Considering a Trumpet  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The flow pattern in the uphill teeming process has been found to be closely related to the quality of ingots and further to affect the yield of ingot production, which is crucial for the steel making process. The formation of non-metallic inclusion and entrapment of mold flux has been considered to be affected by the flow pattern in the gating system and molds by many previous researchers. The aim of this study is to investigate the flow pattern of steel in the gating system and molds during ...

Tan, Zhe

2012-01-01

262

Tool steel quality and surface finishing of plastic molds  

Directory of Open Access Journals (Sweden)

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.

Reinhold Schneider

2010-01-01

263

Microstructure and mechanical properties of high Nb containing TiAl alloy parts fabricated by metal injection molding  

Energy Technology Data Exchange (ETDEWEB)

Metal injection molding (MIM) process was applied to fabricate parts of high Nb containing TiAl alloys with a nominal composition of Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y (at.%), and the effects of sintering parameters on their microstructures and mechanical properties, as well as the fractographies after tensile tests were investigated. Results show that for sintering of the alloy in vacuum, effective densification took place in the temperature range 1460-1480 deg. C. Sintering at too high a temperature or too long a time will result in distortion or warpage of the sintered body or coarsening of the lamellar colony. When the optimum sintering parameters (1480 deg. C, 2 h) were chosen, the alloy with the relative density of 96.2% was obtained. The microstructure was homogenous and fine-grained near lamellar structure, consisting of {alpha}{sub 2}/{gamma} lamellar colonies with an average size of 60 {mu}m, small amounts of {beta} phase, few boride rods and yttrium oxide precipitates. Its compressive strength, compressibility, ultimate tensile strength and plastic elongation were 2839 MPa, 34.9%, 382 MPa and 0.46%, respectively. At tensile tests, translamellar fracture was the predominant mode and the microcracks often originated from pores and the interfaces of borides/matrix and {beta} phase/matrix.

Zhang Haoming, E-mail: zhmustb@yahoo.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083 (China); He Xinbo [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, University of Science and Technology Beijing, Beijing 100083 (China); Zhao Liming [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083 (China)

2009-11-25

264

Microstructure and mechanical properties of high Nb containing TiAl alloy parts fabricated by metal injection molding  

International Nuclear Information System (INIS)

Metal injection molding (MIM) process was applied to fabricate parts of high Nb containing TiAl alloys with a nominal composition of Ti-45Al-8.5Nb-0.2W-0.2B-0.02Y (at.%), and the effects of sintering parameters on their microstructures and mechanical properties, as well as the fractographies after tensile tests were investigated. Results show that for sintering of the alloy in vacuum, effective densification took place in the temperature range 1460-1480 deg. C. Sintering at too high a temperature or too long a time will result in distortion or warpage of the sintered body or coarsening of the lamellar colony. When the optimum sintering parameters (1480 deg. C, 2 h) were chosen, the alloy with the relative density of 96.2% was obtained. The microstructure was homogenous and fine-grained near lamellar structure, consisting of ?2/? lamellar colonies with an average size of 60 ?m, small amounts of ? phase, few boride rods and yttrium oxide precipitates. Its compressive strength, compressibility, ultimate tensile strength and plastic elongation were 2839 MPa, 34.9%, 382 MPa and 0.46%, respectively. At tensile tests, translamellar fracture was the predominant mode and the microcracks often originated from pores and the interfaces of borides/matrix and ? phase/matrix.

2009-11-25

265

Diseo de un molde de inyeccin con un sistema de cavidades intercambiables y deslizantes / DESIGN OF INJECTION MOULD WITH A SYSTEM OF INTERCHANGEABLE AND SLIDING CAVITIES  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish El presente trabajo tuvo como objetivo principal disear un molde de inyeccin de probetas normalizadas, destinadas a ensayos mecnicos, utilizando un sistema novedoso de cavidades intercambiables y deslizantes. El diseo que se propone se basa en el uso de insertos o postizos, para el moldeo indivi [...] dualizado de diferentes probetas. Actualmente, existe la tendencia a disear moldes con postizos intercambiables que ofrecen facilidades para la obtencin de probetas diversas, con la caracterstica de fijarse al sistema de placas mediante tornillos. Al estar sujetos de esa forma, presentan dificultades importantes al momento de montarlos y desmontarlos, para un cambio rpido de cavidades de moldeo. Para ello se requiere de un gran esfuerzo manual e inversin de tiempo. Partiendo de esa experiencia y de las tendencias recientes en la industria a usar moldes con sistemas de cambio rpido, el presente trabajo plantea el diseo con un sistema de postizos intercambiables y deslizantes, bajo las especificaciones de las normas ASTM 6141 e ISO 294-1. Con tal fin, se han diseado dos postizos, uno para la inyeccin de probetas tipo halterio y otro para barras rectangulares, las cuales pueden usarse en mltiples ensayos mecnicos (traccin, flexin e impacto). Para modelar y validar el molde diseado y los postizos propuestos se usaron los programas Pro/ENGINEER y C-MOLD. Se formularon dos propuestas preliminares, considerando los dos movimientos posibles de los postizos en el sistema de placas de la mquina de inyeccin: vertical y horizontal. La evaluacin comparativa de los pros y los contras de cada molde favoreci al sistema horizontal, debido a sus facilidades de manipulacin y garantas para inmovilizar los postizos Abstract in english The main aim of this work was the design of an injection mould with the purpose of preparing test specimens, using a new system of interchangeable and sliding cavities. The proposed mould is able to hold inserts able to, manufacture the individualized test specimen by injection moulding. Nowadays, t [...] he trend toward the design of moulds with interchangeable cavities intended for easing the process of obtaining diverse plastic parts in the same mould, present the characteristic of fixing the system of plates by means of several screws. This system presents important drawback, at the moment of a rapid change of them, like the trend of having to make a great manual effort and to spend considerable amount of time. The present work presents the design of a mould with sliding and interchangeable cavities, under ASTM 6141 and ISO 294-1 norms. The design of two interchangeable and sliding cavities is developed: one with the purpose of producing tensile test specimen and the other for manufacturing rectangular bars (for flexion or impact tests). In order to shape and validate the designed mold and the proposed cavities, the Pro/ENGINEER and C-MOLD software were used. Two preliminary designs were formulated considering horizontal or vertical possible movements of the interchangeable cavities in the system of plates of the injection mould. The comparative evaluation of the advantages and disadvantages of every mould favoured the horizontal system, due to its operational facility associated with the guaranty of an easy manipulation and immobilization of cavities

Mara V, Candal; Mara I, Hernndez.

266

Injection Molding Parameter Optimization of Ti-6Al-4V Powder Mix With Palm Stearin and Polyethylene for Highest Green Strength Using Taguchi Method  

Science.gov (United States)

Taguchi method of L27 (313) orthogonal array is used in this paper as a tool in optimization of Metal injection molding (MIM) parameters for the highest green strength. Parameters optimized are the injection pressure, injection temperature, powder loading, mold temperature, holding pressure and injection speed. Besides those, interaction of the injection pressure, injection temperature and powder loading were studied. The metal powder of Ti-6Al-4V is mixed with binder 60wt% of palm stearin and 40wt% of polyethylene successfully injected at optimum parameter condition: 350 bar of injection pressure, 140 C of injection temperature, 65vol% of powder loading, 50 C of mold temperature, 600 bar of holding pressure, and 10 ccm/s of the injection rate. Analysis of variance (ANOVA) for the best signal to noise ratio (S/N) presents the contribution of the parameters to the quality characteristic (green strength). Results show that the mold temperature has highest significant percentage (27.59%) followed by powder loading (15.44%) and injection pressure (12.30%). Nevertheless, the analysis of variance does not show any contribution from interaction.

Nor, N. H. Mohamad; Muhamad, N.; Ruzi, M.; Ahmad, S.; Ibrahim, M. H. I.; Jamaludin, K. R.

2011-01-01

267

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

Directory of Open Access Journals (Sweden)

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.

F. L. Amorim

2004-06-01

268

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

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

269

Moldagem por injeo de ps cermicos: remoo da parafina e do polipropileno utilizados como veculo orgnico Ceramic injection molding: removal of pafafin and polypropylene used as organic binder  

Directory of Open Access Journals (Sweden)

Full Text Available A moldagem por injeo de ps cermicos tem se tornado um processo altamente atrativo por aliar a versatilidade e a produtividade da moldagem por injeo convencional s propriedades inerentes aos materiais cermicos. A remoo do ligante, usado como veculo orgnico nesse processo, uma das etapas crticas para a produo de peas cermicas sem defeitos. Neste trabalho avaliou-se a influncia da geometria das peas injetadas na remoo do ligante, tanto por imerso em solvente como por decomposio trmica. Alumina em p foi misturada fisicamente a um ligante composto por polipropileno [PP], parafina [PW] e cido esterico [AE]. As peas com diferentes geometrias foram mantidas imersas em hexano, secas sob vcuo e acompanhada a variao de massa devido solubilizao do PW e AE. A determinao da porosidade das peas, realizada por meio das isotermas de adsoro/desoro de nitrognio, mostrou um aumento de porosidade de 0,5% volume para aproximadamente 20% volume aps a imerso em solvente. A remoo trmica do PP remanescente produziu hidrocarbonetos alifticos e compostos insaturados, determinados e quantificados por espectroscopia de infravermelho, que permearam a estrutura porosa da pea. A geometria das peas tem grande influncia na remoo do ligante, podendo afetar no s a qualidade do produto final, mas tambm as etapas subseqentes 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.

Ricardo V. B. Oliveira

2004-09-01

270

Moldagem por injeo de ps cermicos: remoo da parafina e do polipropileno utilizados como veculo orgnico / Ceramic injection molding: removal of pafafin and polypropylene used as organic binder  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A moldagem por injeo de ps cermicos tem se tornado um processo altamente atrativo por aliar a versatilidade e a produtividade da moldagem por injeo convencional s propriedades inerentes aos materiais cermicos. A remoo do ligante, usado como veculo orgnico nesse processo, uma das etapas [...] crticas para a produo de peas cermicas sem defeitos. Neste trabalho avaliou-se a influncia da geometria das peas injetadas na remoo do ligante, tanto por imerso em solvente como por decomposio trmica. Alumina em p foi misturada fisicamente a um ligante composto por polipropileno [PP], parafina [PW] e cido esterico [AE]. As peas com diferentes geometrias foram mantidas imersas em hexano, secas sob vcuo e acompanhada a variao de massa devido solubilizao do PW e AE. A determinao da porosidade das peas, realizada por meio das isotermas de adsoro/desoro de nitrognio, mostrou um aumento de porosidade de 0,5% volume para aproximadamente 20% volume aps a imerso em solvente. A remoo trmica do PP remanescente produziu hidrocarbonetos alifticos e compostos insaturados, determinados e quantificados por espectroscopia de infravermelho, que permearam a estrutura porosa da pea. A geometria das peas tem grande influncia na remoo do ligante, podendo afetar no s a qualidade do produto final, mas tambm as etapas subseqentes 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.

Ricardo V. B., Oliveira; Eduardo A., Pinheiro; Valdir, Soldi; Alfredo T. N., Pires; Mrcio C., Fredel.

271

Moldes de ABS construdos pelo processo de modelagem por fuso e deposio para injeo de PP e PEBD / PP and LDPE injection in ABS molds built with fused deposition modeling  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Os processos de prototipagem rpida (Rapid Prototyping - RP) e ferramental rpido (Rapid Tooling - RT) surgiram para reduzir os tempos de desenvolvimento de produtos na fase de projeto diminuindo a necessidade de retrabalhos e, conseqentemente, antecipando a entrada de novos produtos no mercado. Ne [...] ste trabalho foi utilizada uma das tecnologias de prototipagem rpida, denominada Modelagem por Fuso e Deposio (FDM), na construo de moldes em ABS com o objetivo de investigar sua aplicao na moldagem por injeo de termoplsticos. Amostras das peas injetadas foram submetidas a ensaios de difrao de raios X, dureza Shore D e trao. Os resultados mostraram a viabilidade de fabricar pequenos lotes de peas em PEBD e PP com propriedades mecnicas bastante similares s encontradas em peas moldadas em moldes metlicos. 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.

Jos A., Foggiatto; Carlos H., Ahrens; Gean V., Salmoria; Alfredo T. N., Pires.

272

Moldes de ABS construdos pelo processo de modelagem por fuso e deposio para injeo de PP e PEBD PP and LDPE injection in ABS molds built with fused deposition modeling  

Directory of Open Access Journals (Sweden)

Full Text Available Os processos de prototipagem rpida (Rapid Prototyping - RP e ferramental rpido (Rapid Tooling - RT surgiram para reduzir os tempos de desenvolvimento de produtos na fase de projeto diminuindo a necessidade de retrabalhos e, conseqentemente, antecipando a entrada de novos produtos no mercado. Neste trabalho foi utilizada uma das tecnologias de prototipagem rpida, denominada Modelagem por Fuso e Deposio (FDM, na construo de moldes em ABS com o objetivo de investigar sua aplicao na moldagem por injeo de termoplsticos. Amostras das peas injetadas foram submetidas a ensaios de difrao de raios X, dureza Shore D e trao. Os resultados mostraram a viabilidade de fabricar pequenos lotes de peas em PEBD e PP com propriedades mecnicas bastante similares s encontradas em peas moldadas em moldes metlicos.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.

Jos A. Foggiatto

2004-12-01

273

Fabrication of combined-scale nano- and microfluidic polymer systems using a multilevel dry etching, electroplating and molding process  

DEFF Research Database (Denmark)

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.

Tanzi, Simone; ?stergaard, Peter Friis

2012-01-01

274

TECHNIQUES AND RESULTS FOR FIBER LENGTH DISTRIBUTION DETERMINATION AS A FUNCTION OF THICKNESS IN LONG FIBER REINFORCED INJECTION MOLDED THERMOPLASTICS  

Energy Technology Data Exchange (ETDEWEB)

A novel measurement technique was developed to obtain unbiased fiber length distribution (FLD) measurements at specified locations in the thickness of the sample. This technique relies on elastic energy stored in long fiber thermoplastics (LFT), which is released during partially constrained burn-off. This release results in an increase of thickness dimension of the sample and partial disentanglement, allowing sample selection and subsequent filament separation. Quantitative FLD results and the measurement technique are discussed in detail. The FLD in long fiber reinforced injection molded thermoplastics is shown to vary as a function of thickness.

Kunc, Vlastimil [ORNL; Frame, Barbara J [ORNL; Pryor, Jeff M [ORNL; Nguyen, Ba N. [Pacific Northwest National Laboratory (PNNL); TuckerIII, Charles L. [University of Illinois, Urbana-Champaign; Case, Scott [Virginia Polytechnic Institute and State University; Penumadu, Dayakar [University of Tennessee, Knoxville (UTK); Guffey, Eric W [University of Tennessee, Knoxville (UTK)

2008-01-01

275

Portable CE system with contactless conductivity detection in an injection molded polymer chip for on-site food analysis  

Science.gov (United States)

We present a compact portable chip-based capillary electrophoresis system that employs capacitively coupled contactless conductivity detection (C4D) operating at 4 MHz as an alternative detection method compared to the commonly used optical detection employing laser-induced fluorescence. The disposable chip for this system is fabricated out of PMMA using injection molding; the electrodes are screen-printed or thin-film electrodes. The system allows the measurement of small ions like Li, Na, K typically present in foodstuff like milk and mineral water as well as acids in wine.

Becker, Holger; Mhlberger, Holger; Hoffmann, Werner; Clemens, Thomas; Klemm, Richard; Grtner, Claudia

2008-03-01

276

Liquid composite molding-processing and characterization of fiber-reinforced composites modified with carbon nanotubes  

Science.gov (United States)

The increasing demand in fiber-reinforced plastics (FRPs) necessitates economic processing of high quality, like the vacuum-assisted resin transfer molding (VARTM) process. FRPs exhibit excellent in-plane properties but weaknesses in off-plane direction. The addition of nanofillers into the resinous matrix phase embodies a promising approach due to benefits of the nano-scaled size of the filler, especially its high surface and interface areas. Carbon nanotubes (CNTs) are preferable candidates for resin modification in regard of their excellent mechanical properties and high aspect ratios. However, especially the high aspect ratios give rise to withholding or filtering by fibrous fabrics during the impregnation process, i.e. length dependent withholding of tubes (short tubes pass through the fabric, while long tubes are restrained) and a decrease in the local CNT content in the laminate along the flow path can occur. In this study, hybrid composites containing endless glass fiber reinforcement and surface functionalized CNTs dispersed in the matrix phase were produced by VARTM. New methodologies for the quantification of the filtering of CNTs were developed and applied to test laminates. As a first step, a method to analyze the CNT length distribution before and after injection was established for thermosetting composites to characterize length dependent withholding of nanotubes. The used glass fiber fabric showed no perceptible length dependent retaining of CNTs. Afterward, the resulting test laminates were examined by Raman spectroscopy and compared to reference samples of known CNT content. This Raman based technique was developed further to assess the quality of the impregnation process and to quantitatively follow the local CNT content along the injection flow in cured composites. A local decline in CNT content of approx. 20% was observed. These methodologies allow for the quality control of the filler content and size-distribution in CNT based hybrid composites.

Zeiler, R.; Khalid, U.; Kuttner, C.; Kothmann, M.; Dijkstra, D. J.; Fery, A.; Altstdt, V.

2014-05-01

277

Development of sintered titanium base hard alloy by metal injection molding; Kinzoku funmatsu shashutsu seikeiho ni yoru Ti kikoshitsu shoketsu zairyo no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

Metal injection molding (MIM) process was applied to Ti-Mo-TiC alloys. Effect of various processing conditions on mechanical properties of sintered compacts was examined. Mixture of Ti, Mo and TiC powders and organic binder were mixed under heating, and were subsequently cooled and crushed for forming a molding material. As debinding process of MIM compact, gas phase extraction by heptane and dissipation by heating were combined. Sintered compact was produced under various heating and dissipation conditions; satisfactory sintered compact was obtained at 773 K or the complete decomposition temperature of the binder for 1.8 ks. After heating and dissipation in nitrogen gas atmosphere, and presintering under reduced pressure, sintering was conducted in vacuum at 1773 K for 7.2 ks; the sintered compact showed same folding strength as those of conventional powder metallurgy alloys. The folding strength largely decreased at the sintering temperature of 1823 K due to coarsening of crystal grains. 3 refs., 7 figs.

Miura, H.; Yokomizo, T. [Kumamoto Univ. (Japan); Tokumoto, K.; Nakahara, K. [Nippon Tungsten Co. Ltd., Saga (Japan)

1998-09-15

278

Trial manufacturing of TiAl parts by injection molding; Shashutsu seikeiho niyoru TiAl buhin keijo no shisaku  

Energy Technology Data Exchange (ETDEWEB)

Manufacturing of a model turbin blade (total length: 85mm) of TiAl by metal injection molding was tried. The compound of the pre-alloyed TiAl powder mixed with organic binder was injected into the die for forming the green of the turbin blade at various temperatures. In the temperature range, 100 degree C {approx} 120 degree C, wholesome green bodies were obtained. After debinding, swelling and crack were frequently observed at the surface corresponding to the thick part of green bodies under the same condition of test-piece. Inorder to improve these defects, it is necessary to optimize further the debinding conditions e.g. decreasing of heating rate. Good sintered body (ralative density>95%) was obtained under the same sintering condotion of test-piece, while a little warp was observed at the ridgeline of blade. The variation of relative densities of the inside of sintered body was within 0.8%. (author)

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

1999-02-22

279

Resin Flow Behavior Simulation of Grooved Foam Sandwich Composites with the Vacuum Assisted Resin Infusion (VARI) Molding Process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Chenhui Zhao; Guangcheng Zhang; Yibo Wu

2012-01-01

280

In-Situ Real Time Monitoring and Control of Mold Making and Filling Processes: Final Report  

Energy Technology Data Exchange (ETDEWEB)

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.

Mohamed Abdelrahman; Kenneth Currie

2010-12-22

 
 
 
 
281

Impact and fatigue properties of injection molded Fe-Ni-C system low alloy steels; Shashutsu seikei ni yoru Fe-Ni-C kei teigokinko no shogeki, hiro hakai tokusei  

Energy Technology Data Exchange (ETDEWEB)

Fe-Ni-C system low alloy steels have been developed to enhance the mechanical properties of Fe-Ni system which is a popular steel for Metal Injection Molding (MIM) process. Although the assessment of dynamic failure properties such as impact and fatigue strengths are important, there are few reports about the dynamic properties of injection molded Fe-Ni-C system low alloy steels at the present time. In this study, the behavior of dynamic properties (impact and fatigue strengths) and carbon control by solvent debinding followed by thermal debinding for Fe-2%Ni-0.7%C low alloy steels produced by MIM process was investigated. Retained carbon contents was precisely controlled to 0.7 mass % by continuous process of thermal debinding and sintering. Dynamic properties of the injection molded steels were superior to those of the conventional P/M steels with the same composition, since the pore structure of the former was finer and more spheroidized as compared to that of the latter. (author)

Miura, H. [Kumamoto University, Kumamoto (Japan). Faculty of Engineering; Miyata, K. [Kumamoto University, Kumamoto (Japan); Otsuka, A.; Achikita, M. [Sumitomo Metal Mining Co. Ltd., Tokyo (Japan)

2000-12-15

282

Influence of process parameters on the weld lines formation in rapid heat cycle molding  

Science.gov (United States)

The insufficient entanglement of the molecular chains at the v-notch of a weld line impairs the mechanical strength and the surface quality of a plastic product. The rapid heat cycle molding technology (RHCM) has been recently used to enhance surface appearance of the parts, by thermally cycling the mold surface temperature. The mold temperature is the key of RHCM technology because it significantly affects productivity, energy efficiency and the quality of the final polymer part. In this work the influence of mold temperature on the weld lines depth and roughness were studied. Three different materials were tested. To investigate the influence of process parameters, a special mold insert was designed and manufactured. Weld lines geometry and roughness were quantitatively characterized by means of a profilometer. Experimental results show that is possible to increase the temperature to 10 C lower than the glass transition to obtain a high-gloss parts without weld lines with a significant reduction of cycle time and energy consumption.

Fiorotto, Marco; Lucchetta, Giovanni

2011-05-01

283

Use of a Naphthalene-Based Binder in Injection Molding Net-Shape Titanium Components of Controlled Porosity  

Energy Technology Data Exchange (ETDEWEB)

We have recently developed a naphthalene-based binder system for use in powder injection molding (PIM) of ceramic and metallic materials. The use of a binder that can be removed via sublimation offers several unique advantages relative to the typical thermoplastic and/or thermoset binders employed in PIM. One of these is that essentially no volume change takes place during debindering. This offers a relatively facile method of introducing porosity into a net-shape part of potentially complex geometry. In the study described in this paper, the effects of powder loading and subsequent isostatic compaction on the size and amount of porosity in the components produced by this technique were investigated. In general, it was found that the amount of porosity is inversely proportional to the initial concentration of metal powder in the PIM feedstock. Likewise, average pore size displays a similar relationship with powder loading.

Weil, K. Scott; Nyberg, Eric A.; Simmons, Kevin L.

2005-07-01

284

Survey of molds, yeast and Alicyclobacillus spp. from a concentrated apple juice productive process  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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 37C, 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.

Beatriz de Cssia Martins, Salomo; Chalana, Muller; Hudson Couto do, Amparo; Glucia Maria Falco de, Arago.

285

Survey of molds, yeast and Alicyclobacillus spp. from a concentrated apple juice productive process.  

Science.gov (United States)

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 37C, 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

de Cssia Martins Salomo, Beatriz; Muller, Chalana; do Amparo, Hudson Couto; de Arago, Glucia Maria Falco

2014-01-01

286

Survey of molds, yeast and Alicyclobacillus spp. from a concentrated apple juice productive process  

Science.gov (United States)

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 37C, 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.

de Cassia Martins Salomao, Beatriz; Muller, Chalana; do Amparo, Hudson Couto; de Aragao, Glaucia Maria Falcao

2014-01-01

287

Interface conditions of two-shot molded parts  

Science.gov (United States)

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.

Kisslinger, Thomas; Bruckmoser, Katharina; Lucyshyn, Thomas; Langecker, Guenter Ruediger; Resch, Katharina; Holzer, Clemens

2014-05-01

288

Development and characterization of polymer- metallic powder feedstocks for micro-injection molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Micro-Powder Injection Moulding (Micro-PIM) technology is one of the key technologies that permit to fit with the increasing demands for smaller parts associated to miniaturization and functionalization in different application fields. The thesis focuses first on the elaboration and characterization of polymer-powder mixtures based on 316L stainless steel powders, and then on the identification of physical and material parameters related to the sintering stage and to the numerical simulations...

Kong, Xiangji

2011-01-01

289

EXPERIMENTAL STUDY OF STRESS RELAXATION IN THE PROCESS OF COLD MOLDING WITH STRAW  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this article, five kinds of straws were used to do compressing molding experiments on stress relaxation by Electric Versatile Material Machine, with specially designed open mode equipment. According to the data from the transition stage of the compression process, regression equations with different straws were built by selective global fitting or piecewise fitting. In addition, the equations were verified by stress logarithm-time curves. A stress relaxation model of the five straws can be...

2009-01-01

290

Void Prediction During Liquid Composite Molding Processes: Wetting and Capillary Phenomena  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 t...

Abdelwahed, Mohamed Amine Ben; Wielhorski, Yanneck; Bizet, Laurent; Bre?ard, Joe?l

2012-01-01

291

An Approach to Rib Design of Injection Molded Product Using Finite Element and Taguchi Method  

Directory of Open Access Journals (Sweden)

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.

Tian-Syung Lan

2008-01-01

292

Optimization of the replica molding process of PDMS using pennate diatoms  

Science.gov (United States)

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.

Hlbikov, D.; Lus, A. T.; Vach, V.; Ector, L.; Hoffmann, L.; Choquet, P.

2012-11-01

293

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - FY 2014 First Quarterly Report  

Energy Technology Data Exchange (ETDEWEB)

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.

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

294

Orthogonal ion injection apparatus and process  

Energy Technology Data Exchange (ETDEWEB)

An orthogonal ion injection apparatus and process are described in which ions are directly injected into an ion guide orthogonal to the ion guide axis through an inlet opening located on a side of the ion guide. The end of the heated capillary is placed inside the ion guide such that the ions are directly injected into DC and RF fields inside the ion guide, which efficiently confines ions inside the ion guide. Liquid droplets created by the ionization source that are carried through the capillary into the ion guide are removed from the ion guide by a strong directional gas flow through an inlet opening on the opposite side of the ion guide. Strong DC and RF fields divert ions into the ion guide. In-guide orthogonal injection yields a noise level that is a factor of 1.5 to 2 lower than conventional inline injection known in the art. Signal intensities for low m/z ions are greater compared to convention inline injection under the same processing conditions.

Kurulugama, Ruwan T; Belov, Mikhail E

2014-04-15

295

Fluidized-Solid-Fuel Injection Process  

Science.gov (United States)

Report proposes development of rocket engines burning small grains of solid fuel entrained in gas streams. Main technical discussion in report divided into three parts: established fluidization technology; variety of rockets and rocket engines used by nations around the world; and rocket-engine equation. Discusses significance of specific impulse and ratio between initial and final masses of rocket. Concludes by stating three important reasons to proceed with new development: proposed engines safer; fluidized-solid-fuel injection process increases variety of solid-fuel formulations used; and development of fluidized-solid-fuel injection process provides base of engineering knowledge.

Taylor, William

1992-01-01

296

Carbon control of Cr-Mo steel by injection molding; Shashutsu seikei ni yoru kikai kozoyo Cr-Mo ko ni okeru tansoryo seigyo  

Energy Technology Data Exchange (ETDEWEB)

The effects of carbon (C) addition and debinding temperature on sintering behavior of Cr-Mo steel compacts shaped by metal injection molding were invetigated to carry out the control of C content of the sintered compacts. The specimens were made of SCM415 steel powder and additional C powder with polyamide binder. The amount of C addition was varied from 0g to 0.6g per 100g of metal powder. The specimens were debound in air at temperatures ranging from 553K to 603K for 7.2ks, and were sintered in argon gas at 1,623K for 7.2ks. The relationship between carbon (C) and oxygen (O) contents of debound compacts versus those of sintered compacts was analyzed by introducing a parameter, {delta}C{sub d} {identical_to} C{sub d} - aO{sub d} (a = C/O atomic weight ratio) which represents the stoichometric ratio of C and O contents of debound compacts (C{sub d} and C{sub d}, respectively). The obtained results showed that the reaction M{sub x}O + C {yields} xM + CO (M=Metal element) is dominant for reducing oxides during sintering process and the excess or shortage of C reducing oxides in compact can be estimated successfully by {delta}{sub d} introduced in this study. (author)

Jinushi, H. [Fukuyama University, Hiroshima (Japan). Faculty of Engineering; Kyogoku, H. [Kinki University, Osaka (Japan). Faculty of Engineering; Shinohara, K. [Ehime University, Ehime (Japan). Faculty of Engineering; Nakayama, H. [King Invest Co. Ltd., Hiroshima (Japan)

2000-02-15

297

Tensile properties at high temperature of sintered FeAl compacts by injection molding; Shashutsu seikeihoni yoru FeAl shoketsutainon koon incho tokusei  

Energy Technology Data Exchange (ETDEWEB)

The B2 FeAl (Fe-40Al and Fe-48Al (at.%)) sintered compacts were prepared by metal injection molding (MIM) process. Then, tensile tests were performed in air at room temperature, 400 degree C, 600 degree C and 800 degree C. The results obtained were summarized as follows. (1) The Fe-48Al compact had the good 0.2% proof stress and tensile strength more than 600 MPa at room temperature. However, they rapidly decreased with increasing test temperature. On the other hand, the 0.2% proof stress of Fe-40Al compact at 400 degree C and 600 degree C were almost equal to that at room temperature ({approx}300 MPa). The tensile strength of this compact showed the maximum (680 MPa) at 400 degree C. The tensile strength of both compacts went down to less than 100 MPa at 800 degree C. (2) At room temperature, the Fe-40Al compact showed the substantial elongation of 2.3%, while that of Fe-48Al compact was only 0.3%. The elongation of both compacts at 600 degree C showed high value of 25 {approx} 30%. Both compacts changed the fracture mode from brittle to ductile at the temperature range from 400 degree C to 600 degree C. (author)

Kato, K. [National Industrial Research Institute of Nagoya, Nagoya (Japan); Masui, T. [Mie Prefecture Industrial Research Institute, Mie (Japan)

2000-06-15

298

Simulation and Injection Molding of Ring-Shaped Polymer Bonded Nickel Braze Metal Composite Preforms Based on Rheological and Thermal Analyses  

Directory of Open Access Journals (Sweden)

Full Text Available Rheological and thermal properties of LD-PE and LD-PE + 65 vol% Ni composite were examined by viscosity, pvt and thermal conductivity measurements at a wide range of shear rate, temperature and pressure. The typical shear-thinning viscosity of LD-PE polymer melt was enhanced up to four times by adding 65 vol% Ni braze metal particles. LD-PE show increasing specific volume versus temperature, decreasing with pressure and braze particle filler content. Variation of specific volume of LD-PE was reduced to 5% by admixing 65 vol% rigid Ni braze metal particles. Thermal conductivity of LD-PE was increased up to 15 times in the composite, reduced by decreasing pressure at temperature exceeding 80?. Furthermore, thermal analysis was performed in modulated DSC to determine the specific heat capacity in wide temperature range. Viscosity and pvt-data were fitted using Cross-WLF equation and 2-domain Tait-pvt model, respectively. Simulation of LD-PE and LD-PE + 65 vol% Ni composite was performed based on rheological and thermal properties to define processing parameters. Simulation and injection molding of ring-shaped LD-PE + 65 vol% Ni composite braze metal preforms were performed successfully.

Stefan Kirchberg

2013-04-01

299

Influence of stearic acid on the structure and rheological behavior of injection-molded ZTA suspensions  

Science.gov (United States)

The zirconia-toughened-alumina (ZTA) composite powder was exposed to a prior ball milling treatment with a small amount of stearic acid (SA) before the traditional blending process. The effect of different amounts of stearic acid on surface properties of the powder, the particle size distribution of the powder, and the rheological properties of the suspension were systematically studied within the design of experiments. Fourier transformation infrared spectroscopy (FTIR) analysis was used to prove the chemical interaction between the stearic acid and the ZTA powder. The effects of SA content on the particle sizes and their distribution were carefully examined. Rheological properties such as viscosity, yield stress, and power law exponent of the suspensions were determined within a temperature range of 140-170 C. The optimal content of SA to improve the properties of the suspensions was found to be 3 wt.%.

Lin, Cong; Wang, Bo; Cheng, Yao; Wang, Cao

2013-01-01

300

Hypersensitivity pneumonitis in a hardwood processing plant related to heavy mold exposure.  

Science.gov (United States)

Two workers employed in a hardwood floor plant presented symptoms suggestive of hypersensitivity pneumonitis (HP). At that plant, kiln-dried wood often shows moldy growth and is subsequently brought inside for processing. This study evaluated the environment in attempt to identify the causative antigen and verify whether other workers of this and similar plants had or were at risk of developing HP. Dust from dust-removing systems and molds on the surface of wood planks were collected and air samples taken from a sister plant. Blood samples, spirometry, and symptoms' questionnaires were obtained from 11 co-workers. Dense Paecilomyces growth was observed on the surface of the dried processed wood in the index plant. This fungal genus was not detected in the sister plant. An additional worker had symptoms suggestive of HP, and his bronchoalveolar lavage revealed a lymphocytic alveolitis. The 3 confirmed cases of HP and the other 10 workers had positive specific IgG antibodies to Paecilomyces. We report 3 cases of HP out of 13 workers and a 100% sensitization to molds in workers of a hardwood processing plant. This rate is much higher than what is commonly seen in other environments associated with HP. The drying process is suspected of being responsible for the massive Paecilomyces contamination likely responsible for the HP. PMID:16621767

Veillette, Marc; Cormier, Yvon; Isral-Assayaq, Evelyne; Meriaux, Anne; Duchaine, Caroline

2006-06-01

 
 
 
 
301

EXPERIMENTAL STUDY OF STRESS RELAXATION IN THE PROCESS OF COLD MOLDING WITH STRAW  

Directory of Open Access Journals (Sweden)

Full Text Available In this article, five kinds of straws were used to do compressing molding experiments on stress relaxation by Electric Versatile Material Machine, with specially designed open mode equipment. According to the data from the transition stage of the compression process, regression equations with different straws were built by selective global fitting or piecewise fitting. In addition, the equations were verified by stress logarithm-time curves. A stress relaxation model of the five straws can be summarized by an expression involving the summation of exponential decay terms. This expression provides reference for reducing the specific energy consumption and increasing the pellet density.

Jian-Jun Hu

2009-08-01

302

Surface wettability enhancement of silicone hydrogel lenses by processing with polar plastic molds.  

Science.gov (United States)

In the quest for hydrogel contact lenses with improved extended wear capability, the use of siloxane moieties in the lens materials was investigated. However, the introduction of hydrophobic siloxane groups gave rise to wettability and lipidlike deposit problems. It was found that when polysiloxane-based compositions for hydrogels were processed with polar plastic molds, such as those fabricated from an acrylonitrile-based polymer, the hydrogel lenses fabricated were wettable, with minimized lipidlike deposits. These findings were supported by the wettability of silicone hydrogel films, silicon, and nitrogen element contents near lens surfaces, as well as the results from clinical assessment of silicone hydrogel lenses. PMID:9138069

Lai, Y C; Friends, G D

1997-06-01

303

Sintering and anisotropic dimensional changes of uniaxially pressed compacts of stainless steel powders for metal injection molding. Shashutsu seikei yo stainless ko funmatsu no shoketsu kyodo oyobi ichijiku kaatsu seikeitai no sunpo henka no iho sei  

Energy Technology Data Exchange (ETDEWEB)

In the injection molding generally, the fine powders of the order of several {mu}m, 5-to10 times costlier than the coarse powders used in the press molding, are used from the viewpoints of fluidity during molding and degree of sintering after molding. It is considered that if slighly coarser powders are used, it contributes to cost reduction. In this report, SUS316L powders of both fine ones of 7{mu}m in mean size and coarse ones of 13{mu}m in mean size were deformed under pressure up to low density close to products made by injection molding and the effects of differences of sintering temperatures in the range of 1373-1673K on the sintered behavior were investigated. Also the mechanical properties of tensile test pieces prepared actually by injection molding were examined. A part of the results is as follows: The fine powder specimens reach quickly its relative density of about 90% at low temperatures, but the progress of compacting following the temperature rise beyond the above is slow. the coarse powder specimens are slow in its compacting at low temperatures, but at or above 1623K, they reach density of 95-96%, the same order of fine powder specimens and the rate of dimensional change also shows the similar trend. Those prepared by injection molding shows the same. 8 refs., 7 figs., 2 tabs.

Kuroki, H. (Hiroshima Univ., Hiroshima (Japan). Faculty of Engineering); Komatsu, K. (Shimazu Corp., Tokyo (Japan)); Nishida, T. (Nippon Steel Corp., Tokyo (Japan))

1991-09-25

304

Implications of diamond-turned versus diamond-ground mold fabrication techniques on precision-molded optics  

Science.gov (United States)

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.

Mertus, Lou; Symmons, Alan

2012-10-01

305

Modeling of Crystallization Processes of Cast Iron Grinding Balls in Casting Molds of Improved Design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A new design of casting mold for the production of balls on the conveyor molding machine was developed and modeling the crystallization of cast iron in it was performed. Replacement of the mold design has a positive effect on improving the quality of the balls and their operating factors by reducing the shrinkage defects.

2011-01-01

306

Interphase formation of a resin transfer molded silica-phenolics composites subjected to dynamic impregnation process  

International Nuclear Information System (INIS)

In this study interphase formation of a resin transfer molded (RTMed) silica-phenolics composites subjected to dynamic impregnation process was investigated. The solvent effect on the interphase formation of silica fiber-phenolics composites was evaluated. UV-vis spectra, XPS and electron paramagnetic resonance (EPR) techniques were used to characterize the competitive adsorption of the components of phenolics solution onto silica reinforcement surfaces. Interlaminar shear strength (ILSS) and void content of silica-phenolics composites were also measured. It has been found that phenolics forms distribution gradient over RTM mold with respect to isomeric composition under the effect of solvent, which result, to varying extent, in the inhomogeneity of void content and thus ILSS of a final product. For the first time, it has been shown that the RTM process of silica-phenolics composites is highly solvent-dependent. Our work gives an insight into the role of organic solvent in a RTM solution impregnation processing and provides useful information and trends relating microscopic to macroscopic behavior

2008-05-30

307

Injection molding WPC  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

S T Clair Renard, Carl

2011-01-01

308

Crystallization kinetics and morphology of PBT/MMT and PTT/MMT nanocomposites during injection molding;Cinetica de cristalizacao e morfologia de nanocompositos de PBT/MMT e PTT/MMT durante a moldagem por injecao  

Energy Technology Data Exchange (ETDEWEB)

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)

Favaro, Marcia M.; Branciforti, Marcia C.; Bretas, Rosario E.S., E-mail: mmfavaro@gmail.co [Universidade Federal de Sao Carlos (DEM/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

2009-07-01

309

Properties of the sintered TiAl compacts prepared by injection molding; Shashutsu seikeiho ni yoru TiAl shoketsutai no shotokusei  

Energy Technology Data Exchange (ETDEWEB)

Properties of the sintered TiAl compacts by applying a metal injection molding (M-IM) process to various type of pre-alloyed powders by SHS-crash method were investigated. Results obtained are as follows: 1) Test pieces of Ti-50at%Al intermetallic compounds were prepared under various process conditons ; size and shape of powder, debinding condition, and sintering temperature. When fine spherical-treated powder (average particle size: 10 {mu}m)was used, sintering reaction proceeded rather readily, and then the compacts was more dence and more tough (>400MPa) than the case of coarse powder. 2) Properties of binary sintered compacts with various Ti/Al ratios (45, 48, 50, 52, and 55at%) were invesigated. The compacts except 55at%Al had the relative densities more than 98% and the tensile strength of about 400MPa at room temperature. Tensile strength of 45, 48 and 50at%Al compacts at 800 degree C were almost equal to the strength of those at room temperature. The strength of those compacts at 1,000 degree C, however, went down to about 200MPa.. 3) Properties of ternary sintered compacts (Ti-48Al-2Mo, Ti-50Al-2Mo, Ti-48Al-2Mn, Ti-50Al-2Mn, Ti-48Al-2Cr) were investigated. All compacts had the the raletive densities more than 95%. Ti-rich compacts (Ti-48Al-2Mo, Ti-48Al-2Mn, Ti-48Al-2Cr) had fine microstructures to the binary. Ti-48Al-2Mo compact had the strength of 470MPa. The ductility of ternary compacts at room temperature was lower than that of binary one. (author)

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

1999-02-22

310

Resin Flow Behavior Simulation of Grooved Foam Sandwich Composites with the Vacuum Assisted Resin Infusion (VARI Molding Process  

Directory of Open Access Journals (Sweden)

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.

Yibo Wu

2012-07-01

311

Void Prediction During Liquid Composite Molding Processes: Wetting and Capillary Phenomena  

CERN Multimedia

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.

Abdelwahed, Mohamed Amine Ben; Bizet, Laurent; Brard, Jol

2012-01-01

312

Plastic molds reduce cost of encapsulating electric cable connectors  

Science.gov (United States)

Resin casting of the aluminum master pattern forms a plastic mold for encapsulating a cable connector. An elastomer is injected into the mold and cured. The mold is disassembled leaving an elastomeric encapsulation around the connector.

Knott, D.

1964-01-01

313

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.)

1972-09-18

314

Moldagem por injeo em baixa presso de peas complexas de cermicas avanadas produzidas com ps submicromtricos / Low-pressure injection molding of complex parts of advanced ceramic produced with fine powder  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A moldagem por injeo em baixa presso (MIBP) tem constitudo, nos ltimos anos, uma excelente alternativa para a produo de pequenos lotes de peas cermicas diversificadas e com formas complexas. Esta tcnica de conformao relativamente simples e barata, mas apresenta diversos problemas na et [...] apa de extrao dos ligantes, principalmente quando o p cermico muito fino e as peas possuem grande seo transversal. Neste trabalho descrita uma metodologia especfica para a produo de peas cermicas por moldagem por injeo a baixa presso de alumina submicromtrica (0,4 mim), incluindo a formulao da mistura para injeo, bem como detalhes do processo de extrao dos ligantes orgnicos utilizados na moldagem. Para o desenvolvimento deste processo fez-se necessrio (i) entender melhor o processo de MIBP, (ii) desenvolver a formulao da mistura de p cermico e aditivos orgnicos, (iii) confeccionar moldes adequados para a injeo a baixas presses e (iv) otimizar os parmetros de injeo. A metodologia desenvolvida neste trabalho, possibilita a confeco de peas cermicas complexas, com seo transversal relativamente grande, permitindo uma produo robusta de pequenos lotes de peas cermicas diversificadas com tima 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.

J. E., Zorzi; C. A., Perottoni; J. A. H. da, Jornada.

315

Moldagem por injeo em baixa presso de peas complexas de cermicas avanadas produzidas com ps submicromtricos Low-pressure injection molding of complex parts of advanced ceramic produced with fine powder  

Directory of Open Access Journals (Sweden)

Full Text Available A moldagem por injeo em baixa presso (MIBP tem constitudo, nos ltimos anos, uma excelente alternativa para a produo de pequenos lotes de peas cermicas diversificadas e com formas complexas. Esta tcnica de conformao relativamente simples e barata, mas apresenta diversos problemas na etapa de extrao dos ligantes, principalmente quando o p cermico muito fino e as peas possuem grande seo transversal. Neste trabalho descrita uma metodologia especfica para a produo de peas cermicas por moldagem por injeo a baixa presso de alumina submicromtrica (0,4 mim, incluindo a formulao da mistura para injeo, bem como detalhes do processo de extrao dos ligantes orgnicos utilizados na moldagem. Para o desenvolvimento deste processo fez-se necessrio (i entender melhor o processo de MIBP, (ii desenvolver a formulao da mistura de p cermico e aditivos orgnicos, (iii confeccionar moldes adequados para a injeo a baixas presses e (iv otimizar os parmetros de injeo. A metodologia desenvolvida neste trabalho, possibilita a confeco de peas cermicas complexas, com seo transversal relativamente grande, permitindo uma produo robusta de pequenos lotes de peas cermicas diversificadas com tima qualidade e excelente reprodutibilidade.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.

J. E. Zorzi

2004-09-01

316

Energy saving by changing hydraulically driven injection molding machine into electric motor driven. Chunyu seikeiki Yuatsu kudo no dendo kudoka ni yoru sho energy  

Energy Technology Data Exchange (ETDEWEB)

An attempt was made on saving energy by changing the driving source of an automotive parts injection molding machine from hydraulic power to electric motor power. In the hydraulic system, a drive source pump is operated continuously, whereas 74.3% of the total energy is not used directly to make products, but wasted as a loss in idle operation. A hydraulic system has a structural difficulty to remarkably reduce this loss, and therefore, it was planned to change the system to electric motor driven, and a new injection molding machine was fabricated using a 4.4 kW AC servo motor as the drive source. As a result, the driving energy cost was reduced from 72,274 yen/year to 5,927 yen/year, a reduction to a one-twelfth level. Elimination of oil leakage measures and hydraulic fluid replacement contributed to enhancing the maintenance requirement, and improving the working environment as a result of reduced noise. However, an increase in the investment from 1.83 million yen per machine to 2.63 million yen leaves a problem of future cost reduction by means of reviewing the drive motor types, and reducing the motor capacity. 5 figs., 2 tabs.

Nakamura, I. (Toyoda Gosei Co. Ltd., Aichi (Japan))

1991-02-04

317

Effects of (Cr,Fe)2B borides on hardness in powder-injection-molded product fabricated with Fe-based alloy powders  

International Nuclear Information System (INIS)

In the present study, a powder injection molding (PIM) product containing (Cr,Fe)2B borides was fabricated with Fe-based alloy powders, and its microstructure and hardness were investigated in relation with volume fraction of (Cr,Fe)2B. In the Fe-based alloys designed by the thermodynamic calculation, the volume fractions of (Cr,Fe)2B increased with increasing (XCr+XB) value, and were well matched with those obtained from the thermodynamic calculation. The hardness of the Fe-based alloys linearly increased with increasing volume fraction of (Cr,Fe)2B. When Fe-based alloy powders were injection-molded and sintered at 1165 C, a densified microstructure with almost no pores was obtained. In the sintered microstructure, 56 vol% of (Cr,Fe)2B borides, together with a few pores (porosity; 0.5%), were relatively homogeneously distributed in the tempered martensite matrix, which resulted in the very high hardness over 600 VHN. Such a high hardness suggested that the present Fe-based alloy powders could be readily adopted for fabricating PIM products or for replacing conventional stainless steel PIM products.

2012-10-30

318

Effects of (Cr,Fe){sub 2}B borides on hardness in powder-injection-molded product fabricated with Fe-based alloy powders  

Energy Technology Data Exchange (ETDEWEB)

In the present study, a powder injection molding (PIM) product containing (Cr,Fe){sub 2}B borides was fabricated with Fe-based alloy powders, and its microstructure and hardness were investigated in relation with volume fraction of (Cr,Fe){sub 2}B. In the Fe-based alloys designed by the thermodynamic calculation, the volume fractions of (Cr,Fe){sub 2}B increased with increasing (X{sub Cr}+X{sub B}) value, and were well matched with those obtained from the thermodynamic calculation. The hardness of the Fe-based alloys linearly increased with increasing volume fraction of (Cr,Fe){sub 2}B. When Fe-based alloy powders were injection-molded and sintered at 1165 Degree-Sign C, a densified microstructure with almost no pores was obtained. In the sintered microstructure, 56 vol% of (Cr,Fe){sub 2}B borides, together with a few pores (porosity; 0.5%), were relatively homogeneously distributed in the tempered martensite matrix, which resulted in the very high hardness over 600 VHN. Such a high hardness suggested that the present Fe-based alloy powders could be readily adopted for fabricating PIM products or for replacing conventional stainless steel PIM products.

Do, Jeonghyeon; Jeon, Changwoo; Paul Kim, Choongnyun; Lee, Byeong-Joo [Center for Advanced Aerospace Material, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, Sunghak, E-mail: shlee@postech.ac.kr [Center for Advanced Aerospace Material, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, Eon-Sik [Advanced Metallic Materials Research Department, Research Institute of Industrial Science and Technology, Pohang 790-330 (Korea, Republic of); Shik Yoon, Tae [Bestner Co., 146-8 Sangdaewon-dong, Sungnam 462-121 (Korea, Republic of); Su Shin, Yang [New Growth Technology Strategy Department, POSCO, Seoul 135-777 (Korea, Republic of)

2012-10-30

319

Efecto del proceso de transformacin sobre el coeficiente de endurecimiento por deformacin en polmeros / Effect of the molding process on the strain hardening index by deformation in polymers  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish El objetivo principal de este trabajo fue analizar el comportamiento del coeficiente de endurecimiento por deformacin (Gp) en materiales plsticos, para diferentes condiciones de inyeccin y velocidades de deformacin durante el ensayo mecnico. Se inyectaron probetas tipo I de Polietileno de Alta [...] Densidad (PEAD 2811) modificando las variables del proceso de inyeccin (presin, velocidad y temperatura de inyeccin). Se evaluaron las propiedades tensiles y se determinaron los parmetros mecnicos (Mdulo de Young, Esfuerzo y Deformacin a la fluencia y Gp). Se encontr que el Gp disminuye con la presin de inyeccin y se mantiene constante al incrementar la temperatura de inyeccin, sin embargo, con la velocidad de inyeccin presenta una dualidad de comportamientos, es decir a bajas velocidades de ensayo aumenta, mientras que a altas velocidades disminuye el coeficiente. Tambin se obtuvo que a medida que la velocidad de deformacin 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

Morales, Rosa; Candal, Mara; Robles, Jennifer.

320

Selected methods of modelling of polymer during the injection moulding process  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The purpose of present paper was presenting chosen results of investigations on polymer flow during mould cavity filling phase of injection process. Advancement in the simulation software make possible to model more phenomena occurring during polymer flow in injection molding process.Design/methodology/approach: The results of computer simulations of injection process have been compared with the results of video recording for the plastic flow during filling phase. For the simulating investigations a professional computer software Moldflow Plastics Insight ver. 6.1. has been employed. A specialized injection mould which enables observation and registration of the plastic flow during processing has been employed. The mould enables direct monitoring of the course of phenomena inside the mould cavity in two planes. To record the flow, a digital video camera has been employed. As an example the issue of stream flow (jeting have been described.Findings: The results of the investigations enabled documenting of specific phenomena which occur during plastics or their composites injection process. The registered video sequences have been compared with the results of numerical calculations and then it was estimated to what degree the computer simulation of injection process may be useful in practice.Research limitations/implications: The camera enabled to register the flows with the rate of 25 fps. This reduced the scope of the investigations, since at higher plastic flow speeds the registered image became less clear. The investigations were performed on a wide scale, however, only chosen results have been presented.Practical implications: Deep understanding of the phenomena which occur during filling the injection mould may lead to more effective design of the processing tools and shortening of the time for implementation and production time.Originality/value: The transparent sight-glasses have been used, made of a material called Zerodur which is characterized by the coefficient of thermal expansion close to zero.

J. Koszkul

2007-09-01

 
 
 
 
321

Casting and Molding  

Science.gov (United States)

This activity was designed for blind learners, but all types of learners can explore the process used to cast and mold molten metal, glass, and plastics. Using gelatin, the learner will work with a variety of molds to create castings. When the shapes are unmolded, the learner can tactually explore the casts.

Blind, Perkins S.

2012-06-26

322

Nanopatterning planar and non-planar mold surfaces for a polymer replication  

DEFF Research Database (Denmark)

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.

Cech, Jiri; Pranov, Henrik

2013-01-01

323

Magnetic properties of Nd-Fe-B magnets prepared by metal injection molding; Kinzoku idashi seikei de sakuseishita Nd-Fe-B jishaku no jiki tokusei  

Energy Technology Data Exchange (ETDEWEB)

The Nd-Fe-B alloy powder was kneaded at 283K with the binder of methylcellulose dissolved in water. The mixture was infected at temperature 293K in a die of 353K, which is slightly above the sol-gel transformation temperature of methylcellulose. The magnetic field of 1.35 (MA/m) was applied to produce the alignment of easy magnetization direction of alloy powder in a molded body. The molded body was dehydrated by the vacuum-drying method to suppress the oxidation of alloy powder. By heating it in H2 at 573K for 0.5H, about 80% of carbon in binder was removed, although the oxygen in binder remained unremoved. With the molded body added 2wt% methylcellulose, these treatments can allow to suppress the residual contents of oxygen and carbon in the revolted sintered Nd-Fe-B alloy within less than 9000ppm and 800ppm, respectively. The highest coercive force (iHc) and maximum energy product (BH)max for a sintered anisotropic magnet prepared be the above mentioned process are 1.10(MA/m) and 287.2(kJ/m{sup 3}), respectively. 4 refs., 11 figs., 2 tabs.

Yamashita, O. [Sumitomo Special Metals Co. Ltd., Osaka (Japan)

1995-09-15

324

Nanopattern insert molding  

Energy Technology Data Exchange (ETDEWEB)

A new method was investigated to produce nanopatterns on polymeric surfaces with high resolution, good productivity, and low cost. It has certain advantages when compared with such conventional techniques as nanoimprint lithography (NIL), hot embossing, and injection molding. Polyvinyl alcohol (PVA) was utilized for preparation of the stamp with nanopatterns on its surface. The nanoimprinted PVA film was inserted into the cavity and the polymer melt was injected into the mold. Nanopatterns with pillars smaller than 100 nm were produced on the polymeric surface. The water soluble PVA film was used as the inserted template to overcome the difficulties of releasing the nanopatterned film from the substrate.

Kim, S H; Youn, J R [Research Institute of Advanced Materials (RIAM), Department of Materials Science and Engineering, Seoul National University, 56-1, Shinlim-Dong, Gwanak-gu, Seoul, 151-744 (Korea, Republic of); Jeong, J H, E-mail: jaeryoun@snu.ac.kr [Nano-Mechanical Systems Research Center, Intelligent and Precision Machinery Research Division, Korea Institute of Machinery and Materials, 104 Sinseongno, Yuseong-gu, Daejeon, 305-343 (Korea, Republic of)

2010-05-21

325

Nanopattern insert molding  

Science.gov (United States)

A new method was investigated to produce nanopatterns on polymeric surfaces with high resolution, good productivity, and low cost. It has certain advantages when compared with such conventional techniques as nanoimprint lithography (NIL), hot embossing, and injection molding. Polyvinyl alcohol (PVA) was utilized for preparation of the stamp with nanopatterns on its surface. The nanoimprinted PVA film was inserted into the cavity and the polymer melt was injected into the mold. Nanopatterns with pillars smaller than 100 nm were produced on the polymeric surface. The water soluble PVA film was used as the inserted template to overcome the difficulties of releasing the nanopatterned film from the substrate.

Kim, S. H.; Jeong, J. H.; Youn, J. R.

2010-05-01

326

Heat Transfer and Property Development in Liquid Silicone Rubber Molding.  

Science.gov (United States)

Molding of liquid silicone elastomers is much simpler and more energy efficient than the conventional method, since the low viscosity reactants, monomers or prepolymers, can be easily injected into the mold without having high injection and clamping force...

C. W. Macosko

1984-01-01

327

Silicon micro-mold  

Science.gov (United States)

The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

Morales, Alfredo M. (Livermore, CA)

2006-10-24

328

Brightness field and luminance distribution of light guiding plate using micro molding  

Science.gov (United States)

This research points out the brightness field and luminance distribution of the microstructure of a light guiding plate by micro injection molding (MIM) and micro injection-compression molding (MICM). The process of a light guiding plate includes photo-etching, micro molding techniques (MIM and MICM), and optical field measurement. The results show that the luminance of microstructure of light guiding plate made by MICM is better than those made by MIM. The results also indicate the most important processing parameter is the mold temperature for the luminance distribution of light guiding plate whether made by MIM or MICM. The maximum luminance of the light guiding plate is the 80 Nit (cd/m2) on micro molding. The brightness field distribution of light guiding plate made by MICM is more uniform than those made by MIM for the same processing parameters. The micro injection-compression molding is a more suitable process than micro injection molding for the fabrication of light guiding plate on a backlighting unit.

Huang, Chiung-Fang; Lee, Jeou-Long; Shen, Yung-Kang; Lin, Yi; Wu, Chih-Wei

2009-11-01

329

Polyamide from lactams by reactive rotational molding via anionic ring-opening polymerization: Optimization of processing parameters  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A reactive rotational molding (RRM) process was developed to obtain a PA6 by activated anionic ring-opening polymerization of epsilon-caprolactam (APA6). Sodium caprolactamate (C10) and caprolactam magnesium bromide (C1) were employed as catalysts, and difunctional hexamethylene-1,6-dicarbamoylcaprolactam (C20) was used as an activator. The kinetics of the anionic polymerization of !-caprolactam into polyamide 6 was monitored through dynamic rheology and differential scanning calorimetry meas...

Barhoumi, N.; Maazouz, A.; Jaziri, M.; Abdelhedi, R.

2013-01-01

330

Investigation of the shear thinning behavior of epoxy resins for utilization in vibration assisted liquid composite molding processes  

Science.gov (United States)

Efficient production and consumption of energy are of greatest importance for contemporary industries and their products. This has led to an increasing application of lightweight materials in general and of Carbon Fiber Reinforced Plastics (CFRP) in particular. However, broader application of CFRP is often limited by high costs and manual labor production processes. These constraints are addressed by Liquid Composite Molding (LCM) processes. In LCM a dry fibrous preform is placed into a cavity and infiltrated mostly by thermoset resins; epoxy resins are wide spread in CFRP applications. One crucial parameter for a fast mold filling is the viscosity of the resin, which is affected by the applied shear rates as well as temperature and curing time. The work presented focuses on the characterization of the shear thinning behavior of epoxy resins. Furthermore, the correlation with the conditions in vibration assisted LCM processes, where additional shear rates are created during manufacture, is discussed. Higher shear rates result from high frequencies and/or high amplitudes of the vibration motions which are created by a vibration engine mounted on the mold. In rheological investigations the shear thinning behavior of a representative epoxy resin is studied by means of rotational and oscillatory experiments. Moreover, possible effects of shear rates on the chemical curing reaction are studied. Here, the time for gelation is measured for different levels of shear rates in a pre-shearing phase. Based on the rheological studies, the beneficial effect of vibration assistance in LCM processes with respect to mold filling can further be predicted and utilized.

Meier, R.; Kirdar, C.; Rudolph, N.; Zaremba, S.; Drechsler, K.

2014-05-01

331

Simulation of the Vacuum Assisted Resin Transfer Molding (VARTM) process and the development of light-weight composite bridging  

Science.gov (United States)

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.

Robinson, Marc J.

332

Precision compression molding of chalcogenide glass optical elements  

Science.gov (United States)

Precision glass molding process (GMP) is a promising process to manufacture small precision optical elements in large volume. In this paper, we report on the fabrication of a molded chalcogenide glass lens as an optical element. A set of mold was designed and manufactured with silicon carbide material for the molding test. The structure of the mold set was semi-closed and detachable which can make the molded lens easy releasing with non-invasion. The surfaces of the mold cores are coated with thin protecting DLC film to relieve adhesion problem and increase the working life. Experiments were also performed using a precision glass molding machine Toshiba GMP-311V to determine the molding parameters i.e. molding temperature, pressure and cooling rate. The glass lens breakage during precision molding process was analyzed according to the glass property and the molding parameters. By modifying the mold design and optimization the processing parameters, ultimately achieve the desired molded lens.

Qi, Chaowei; Ma, Tao; Chen, Fan

2013-12-01

333

Graphene-coated Si mold for precision glass optics molding.  

Science.gov (United States)

Despite many attractive properties and well-developed micro/nano manufacturing technologies based on silicon (Si) wafers, severe adhesions between Si and glass at high temperature have limited its application as a mold material in precision glass molding. In this Letter, a coating using carbide-bonded graphene is introduced to build nonstick Si molds for glass molding. The coating has extraordinary mechanical properties and can effectively prevent Si-glass adhesion under high temperature. We demonstrated fabrications of a Fresnel lens and glass parts with micrometer pillars using graphene-coated Si molds. This newly developed process enables the use of Si as a mold material to fabricate sophisticated structures with high-precision dimensions that was not previously available. This technology will greatly improve precision glass molding process and allow high-precision low-cost glass optics to be manufactured in large quantity. PMID:23939130

He, Peng; Li, Lei; Yu, Jianfeng; Huang, Wenyi; Yen, Ying-Chieh; Lee, L James; Yi, Allen Y

2013-07-15

334

Molded optics design and manufacture  

CERN Document Server

While several available texts discuss molded plastic optics, none provide information on all classes of molded optics. Filling this gap, Molded Optics: Design and Manufacture presents detailed descriptions of molded plastic, glass, and infrared optics. Since an understanding of the manufacturing process is necessary to develop cost-effective, producible designs, the book extensively covers various manufacturing methods, design guidelines, trade-offs, best practices, and testing of critical parameters. It also discusses topics that often arise when designing systems with molded optics, such as

Schaub, Michael

2007-01-01

335

Characteristics of Fe-9. 6% Si-5. 4% Al alloy produced by metal injection molding with gas-atomized powder. Gas-atomized Fe-9. 6% Si-5. 4% Al gokin funmatsu womochiita shashutsu seikei zai no shotokusei  

Energy Technology Data Exchange (ETDEWEB)

It is known that Fe-9.6% Si-5.4% Al, popular name Sendust alloy, has excellent magnetic property as soft magnetic materials with high magnetic permeability and magnetic flux density, moreover good wear resistance and suitable for the material of magnetic head etc. Authors have been going on a series of study on this Sendust alloy aimed to promote mechanical properties using the extrusion of powder owing to get high density and fine crystal grain. In this paper, paying attention to injection molding method by metal powder being used widely in recent years, first of all, it was tried to produced the near net shape molding of Sendust alloy which was very brittle materials by injection molding with gas-atmized powders, and then, investigated to make high density and to fine crystal grains. As a result, it was clarified to be able to get the good sintered materials which was the compounds having below 38 {mu} m powder, high mixing ratio in powder volume rate 69%, besides, being possible to mold with injection. 3 refs., 8 figs.

Murakami, M.; Kanazawa, R.; Yanagitani, A.; Tanaka, Y. (Sanyo Special Steel Co. Ltd., Hyogo (Japan))

1991-08-25

336

Effects of injection angles on combustion processes using multiple injection strategies in an HSDI diesel engine  

Energy Technology Data Exchange (ETDEWEB)

Effects of injection angles and injection pressure on the combustion processes employing multiple injection strategies in a high-speed direct-injection (HSDI) diesel engine are presented in this work. Whole-cycle combustion and liquid spray evolution processes were visualized using a high-speed video camera. NOx emissions were measured in the exhaust pipe. Different heat release patterns are seen for two different injectors with a 70-degree tip and a 150-degree tip. No evidence of fuel-wall impingement is found for the first injection of the 150-degree tip, but for the 70-degree tip, some fuel impinges on the bowl wall and a fuel film is formed. For the second injection, a large amount of fuel deposition is observed for the 70-degree tip. Weak flame is seen for the first injection of the 150-degree tip while two sorts of flames are seen for the first injection of the 70-degree tip including an early weak flame and a late luminous film combustion flame. Ignition occurs near the spray tip in the vicinity of the bowl wall for the second injection events of the 150-degree tip, however, it is near the injector tip in the central region of the bowl for the 70-degree tip. The flame is more homogeneous for the 150-degree tip with higher injection pressure with little soot formation similar to a premixed-charge-compression-ignition (PCCI) combustion. For other cases, liquid fuel is injected into flames showing diffusion flame combustion. More soot luminosity is seen for the 70-degree tip due to significant fuel film deposition on the piston wall with fuel film combustion for both injection events. Lower NOx emissions were obtained for the narrow-angle injector due to the rich air-fuel mixture near the bowl wall during the combustion process. 30 refs., 11 figs., 3 tabs.

Tiegang Fang; Robert E. Coverdill; Chia-fon F. Lee; Robert A. White [North Carolina State University, Raleigh, NC (United States). Department of Mechanical and Aerospace Engineering

2008-11-15

337

Measuring the geometrical parameters of steel billets during the molding process by image processing  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this project we present a machine vision system to measure the geometrical parametersand dimensional defects of steel billets (blooms/slabs). Geometrical parameters includewidth, height and length and dimensional defects include camber, rhomboid difference andtorsion. The system has been equipped with a color camera, an industrial computer andother peripheral equipments such as lens, Ethernet Cat-5 cable and camera housing. Digitalimage processing techniques have been used to analyze the s...

Mohammadiha, Nasser

2006-01-01

338

Deformation behavior of injection molded thin-wall metal compact with complex geometry during debinding and sintering; Hakuniku fukuzatsu keijo MIM seikeitai no dasshi oyobi shoketsuji no henkei kyodo  

Energy Technology Data Exchange (ETDEWEB)

The deformation behavior of thin-wall compact with complex geometry prepared by metal injection molding (MIM) during heat debinding and sintering is investigated in detail, and the factors causing deformation are studied based on the result of the investigation. Debinding deformation occurs by the release of residual stresses generated in the compact during molding as well as by viscous creep by gravity. The viscous creep by gravity during heat debinding decreases with increase in the rate of binder removal per unit temperature increase. Deformation associated with the residual stress can be decreased by decreasing the holding pressure at molding. As a factor affecting the sintering deformation, time lag of sintering shrinkage within the compact and the shape of compact due to the temperature difference caused by the contact with the setter can be cited, in addition to creep deformation by the gravity and friction within the setter. 13 refs., 10 figs., 3 tabs.

Miura, R.; Endo, Y.; Sakamoto, R.; Madarame, H. [The Japan Steel Works Ltd., Tokyo (Japan). Technology Research Center

1995-01-15

339

Fabrication of an array-like freeform molding tool for UV-replication using a step and repeat process  

Science.gov (United States)

Artificial compound eye cameras are a prominent approach of next generation wafer level cameras for consumer electronics due to their lower z-height compared to conventional single aperture objectives. In order to address low cost and high volume markets, their fabrication is based on a wafer level UV-replication process. The image quality of compound eye cameras can be increased significantly by the use of refractive freeform arrays (RFFA) instead of conventional microlens arrays. Therefore, we present the fabrication of a RFFA wafer level molding tool by a step and repeat process for the first time. The surface qualities of the fabricated structures were characterized with a white light interferometer.

Dunkel, J.; Wippermann, F.; Brckner, A.; Reimann, A.; Bruer, A.

2013-05-01

340

Process for producing or cleaning high pressure water injection wells  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a process for cleaning a production well. It comprises: stopping the pumping of oil out of the wall; generating an aqueous solution of chlorine dioxide gas under pressure; and injecting under pressure the solution of chlorine dioxide gas into a pumped water injection stream and thereafter under pressure into the well. Also describes is a second process for cleaning a producing well. It comprises: stopping the pumping of oil out of the well; selecting an oxidant reactive with hydrogen sulfide under downhole conditions; and injecting the oxidant under pressure into a pumped water injection stream and thereafter under pressure into a well containing hydrogen sulfide.

Sacco, F.J.

1990-08-07

 
 
 
 
341

Mold Heating and Cooling Pump Package Operator Interface Controls Upgrade  

Energy Technology Data Exchange (ETDEWEB)

The modernization of the Mold Heating and Cooling Pump Package Operator Interface (MHC PP OI) consisted of upgrading the antiquated single board computer with a proprietary operating system to off-the-shelf hardware and off-the-shelf software with customizable software options. The pump package is the machine interface between a central heating and cooling system that pumps heat transfer fluid through an injection or compression mold base on a local plastic molding machine. The operator interface provides the intelligent means of controlling this pumping process. Strict temperature control of a mold allows the production of high quality parts with tight tolerances and low residual stresses. The products fabricated are used on multiple programs.

Josh A. Salmond

2009-08-07

342

Reinforcement of a poly(dimethyl siloxane) mold with high aspect ratio microstructures via a gas-liquid phase sol-gel process  

Science.gov (United States)

A gas-liquid phase sol-gel process was proposed to reinforce a poly(dimethyl siloxane) (PDMS) mold with high aspect ratio microstructures (HARMs) for micromolding. Unlike the conventional sol-gel process or in situ precipitation of silicate nanoparticles (SiO2) inside the PDMS network, the vapor of water and aminomethyl propanol-95 permeated through the PDMS which was pre-soaked with tetraethoxy silane (TEOS), leading to the occurrence of hydrolysis and condensation and reinforcement of the PDMS. The reinforced PDMS mold with HARMs was used for micromolding, and high replication accuracy was achieved. The proposed technique not only prevents the surface of microstructures on the mold from potential agglomeration of particles but also allows for the repetitive usage of the silicon mother mold without damage.

Jheng, Zih-Jian; Fang, Yan-Chao; Lo, Kuo-Feng; Juang, Yi-Je

2009-04-01

343

Processing and warpage evaluation of Package-on-Packages with various epoxy molding compounds  

Science.gov (United States)

We fabricated the top packages of Package-on-Packages (PoPs) with various epoxy molding compounds (EMCs) and measured their warpage using the shadow moir method. The warpage was positive (crying shape) at room temperature due to the smaller coefficients of thermal expansion (CTEs) of the EMCs relative to that of the substrate at temperatures below the glass transition temperature T g . With increasing heating cycle temperature, the warpage decreased and became negative (smiling shape) at approximately 100C, then increased toward positive (crying shape) with further increasing temperature, and finally reached its peak value at the solder reflow temperature of 260C. Such warpage variation behavior is closely related to the CTEs of the EMCs being larger than that of the substrate above T g . Among the packages, the one molded with the EMCs exhibiting the lowest T g and the largest CTE at temperatures above T g exhibited the largest warpage at the solder reflow temperature of 260C.

Jung, Dong-Myung; Kim, Min-Young; Oh, Tae-Sung

2014-03-01

344

PENGEMBANGAN PROSES COMPRESSION MOLDING DALAM PEMBUATAN EDIBLE FILM DARI TEPUNG KORO PEDANG (Canavalia ensiformis L. [Development of Compression Molding Process for Edible Films Production from Canavalia ensiformis (L. Flour  

Directory of Open Access Journals (Sweden)

Full Text Available Edible Films based on Canavalia Ensiformis flour could be made using compression molding process. This research was to investigate temperature (120oC, 130oC, 140oC and pressure ( 0.845 Mpa, 1.690 Mpa, 2.540 Mpa effect on the properties of the film. The compression-molding pressure significantly affected the films thickness, lightness, tensile strength, elongation and Water Vapor Transmition Rate (WVTR. Meanwhile molding temperature only affected films elongation (P<0.05 over the range of conditions studied. Increase in compaction pressure resulted in decreased thickness, tensile strength, elongation with increase in lightness (L* and WVTR. Increasing the molding temperature decreased elongation. Flexible, light-yellow edible films could be produced at a processing temperature of 140oC and compaction pressure of 0.845 Mpa. The films thickness was 0.302 mm; lightness (L* was 68.557, tensile strength was 4.091 Mpa, elongation was 37.547 % and WVTR was 0.001 mg/m2.det.

Triana Lindriati1*

2011-06-01

345

CHARACTERIZATION OF FRICTION DURING THE DEMOLDING OF MICROSTRUCTURES MOLDED BY HOT EMBOSSING  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Today, hot embossing and injection molding belong to the established plastic molding processes in microengineering. Based on experimental findings, a variety of microstructures have been replicated so far using the above processes. However, with increasing requirements regarding the embossing surface and the simultaneous decrease of the structure size down into the nanorange, increasing know-how is needed to adapt hot embossing to industrial standards. To reach this objective, a German-Canadi...

Worgull, M.; Heckele, M.; He?tu, J. -f; Kabanemi, K. -k; Heckele, Mathias

2006-01-01

346

Mold Resources  

Science.gov (United States)

... Suggestions for Reducing Mold Growth in Schools Reduce Indoor Humidity Vent showers and other moisture-generating sources to ... and de-humidifiers. Provide adequate ventilation to maintain indoor humidity levels between 30-60%. Use exhaust fans whenever ...

347

A study on development of the three-dimensional numerical model to analyze the casting process: mold filling and solidification  

Energy Technology Data Exchange (ETDEWEB)

A three dimensional model was developed to analyze the mold filling and solidification in the casting processes. The model uses the VOF method for the calculation of the free surface and the modified equivalent specific heat method for the treatment of the latent heat evolution. The solution procedure is based on the SIMPLER algorithm. The complete model has been validated using the exact solutions for phase change heat transfer and the experimental results of broken water column. The three-dimensional model has been applied to the benchmark test and the results were compared to those from experiment, a two-dimensional analysis, and another three dimensional numerical model.

Mok, Jin Ho [Nano Cast Korea, Incheon (Korea, Republic of)

2005-07-15

348

Metal injection molding of 316L steel powder with a slight amount of B addition; B genso biryo tenka SUS316L kofun no shashutsu seikei  

Energy Technology Data Exchange (ETDEWEB)

Baron (b) is known a the most useful sintering enhancer for ferrous powder. In this study, the effect of B addition on the sintering of metal injection molded SUS316L steel powder compacts was investigated. 0.4 mass% B powder was mixed with the SUS316L steel powder using a centrifugal ball mill to obtain a uniform and fine dispersion. It was shown that the binder removal (%) of the MlMed compacts remarkably droped when 0.4 mass % B was added. The sinterablity of the compacts with the B addition was much affected by the debinding temperature: The compacts debound below 300 degree C were madly sintered to near the theoretical density at relatively low temperature as 1,190 degree C, whereas the compacts debound above 330 degree C had to be heated above 1,240 degree C to obtain near the theoretical density. The mechanical properties of the compacts with the B addition were extremely sensitive to the sintering temperature. It was also shown that the carbon (C) contents of the sintered compacts with the B addition decreased with increasing both debinding and sintering temperatures. (author)

Takekawa, J. [Ishinomaki Senshu University, Miyagi (Japan)

1999-11-15

349

After fogging process in water injected gas turbine systems  

Science.gov (United States)

In gas turbine system with after fogging, water droplets are injected after compressor. After fogging could have more significant potential for enhancement of specific power production compared to inlet fogging alone, since a larger water injection rate is possible. Transient analysis of after fogging process is carried out by using a heat and mass transfer modeling on water droplet evaporation. Transient variables such as droplet diameter and air temperature are evaluated as the droplet evaporation proceeds for different values of initial droplet diameter, pressure ratio of compressor, and water injection ratio. The evaporation time for injected droplets are also estimated. Present results show that the evaporation time decreases sensitively with increasing pressure ratio or initial droplet diameter. However, the effect of water injection ratio on evaporation time is relatively insignificant unless water injection ratio is near the critical ratio.

Kim, Kyoung Hoon; Kim, Dongjoo; Kim, Kyoungjin

2013-12-01

350

Investigation on the Effect of Mold Constraints and Cooling Rate on Residual Stress During the Sand-Casting Process of 1086 Steel by Employing a Thermomechanical Model  

Science.gov (United States)

In this study, the effects of mold constraints and cooling rate on residual stress were analyzed during the shaped casting process. For this purpose, an H-shaped sample was designed in which the contraction of its middle portion is highly restricted by the mold during the cooling process. The effects of an increasing cooling rate combined with mold constraints were analyzed by reducing the thickness of the middle portion in the second sample. A three-dimensional coupled temperature-displacement analysis was performed in finite-element code ABAQUS to simulate residual stress distribution, and then numerical results were verified by the hole-drilling strain-gauge method. It was concluded that the mold constraints have a greater effect on the values of residual stress than the cooling rate (thin section) in steel sand casting. Increasing the cooling rate would increase the amount of residual stress, only in the presence of mold constraints. It is also suggested that employing the elastic-plastic stress model for the sand mold will satisfy the experimental results and avoid exaggerated values of residual stress in simulation.

Baghani, Amir; Davami, Parviz; Varahram, Naser; Shabani, Mohsen Ostad

2014-06-01

351

Investigation on the Effect of Mold Constraints and Cooling Rate on Residual Stress During the Sand-Casting Process of 1086 Steel by Employing a Thermomechanical Model  

Science.gov (United States)

In this study, the effects of mold constraints and cooling rate on residual stress were analyzed during the shaped casting process. For this purpose, an H-shaped sample was designed in which the contraction of its middle portion is highly restricted by the mold during the cooling process. The effects of an increasing cooling rate combined with mold constraints were analyzed by reducing the thickness of the middle portion in the second sample. A three-dimensional coupled temperature-displacement analysis was performed in finite-element code ABAQUS to simulate residual stress distribution, and then numerical results were verified by the hole-drilling strain-gauge method. It was concluded that the mold constraints have a greater effect on the values of residual stress than the cooling rate (thin section) in steel sand casting. Increasing the cooling rate would increase the amount of residual stress, only in the presence of mold constraints. It is also suggested that employing the elastic-plastic stress model for the sand mold will satisfy the experimental results and avoid exaggerated values of residual stress in simulation.

Baghani, Amir; Davami, Parviz; Varahram, Naser; Shabani, Mohsen Ostad

2014-01-01

352

Avaliao da orientao molecular de moldados de polipropileno utilizando figuras de plo obtidas por difrao de raios X / Evaluation of the molecular orientation of injection molded polypropylene using X-ray pole figures  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Neste trabalho, avaliou-se a influncia do perfil de velocidades de injeo utilizado durante a etapa de preenchimento na orientao molecular da fase cristalina, de amostras de polipropileno moldadas por injeo. As medidas de orientao molecular foram realizadas nas posies central e lateral da [...] superfcie de corpos-de-prova de trao injetados, utilizando figuras de plo obtidas por difrao de raios x de altos ngulos. Os resultados demonstraram que as variaes na orientao molecular dos cristalitos de polipropileno esto relacionadas aos diferentes perfis de velocidades de injeo utilizados durante o processamento, sendo que um aumento na velocidade leva a um aumento do grau de orientao. Observou-se que a estrutura cristalina das molculas do polipropileno apresenta orientao bimodal e que o grau de orientao mdio maior na posio lateral do que na posio central. Abstract in english In this work, the influence of the injection velocity profile on the crystalline phase molecular orientation of injection molded polypropylene samples has been evaluated. The molecular orientation has been evaluated both in the central and lateral positions on the surface of the injected tension spe [...] cimens, using x-ray pole figures. The results demonstrated that the variations in molecular orientation of polypropylene crystallites were correlated to the different velocity profiles employed during the processing, showing that an increase in the velocity increases the orientation degree. It has been observed that the crystalline structure of the polypropylene molecules shows bimodal orientation and that the orientation degree at the lateral position is higher than that at the central position.

lvaro M., Almeida; Mrcia C., Branciforti; Rosario E. S., Bretas.

353

Moulded interconnect device fabrication by two shot molding and lasert induced selective activation  

DEFF Research Database (Denmark)

This report on the project ??Molded Interconnect Device (MID) by two shot injection molding and laser induced selective activation? has been submitted to fulfil the requirements for the master project at department of Manufacturing Engineering and Management of Technical University of Denmark (IPL-DTU). MID is defined as an injection molded plastic substrate with electrical infrastructures on the surface and integrates both mechanical and electrical functionalities on the single device. This paper describes many aspects of MID such as the background information, manufacturing process chain, comparative process analysis, applications and specially two shot injection molding and laser induced selective activation in the MID area. There is also an experimental part which contains fabrication of a MID demonstrator, selective metallization as well as characterization. The realization of molded interconnect device was achieved with two innovative processes such as two shot injection molding which combines platetableand none-platetable thermoplastics, and laser induced selective activation which uses a laser to draw circuit on the thermoplastic surface containing laser sensitive additive. Different material combinations such as PEI (GE Ultem 1000) +PPO (GTX 810) and PEEK (Victrex 150GL30) +PPO (GTX 810) were investgated which can be selected electroless plating for metallization. Several plastics such as PC (GE Lexan 500R) and PEEK (Victrex 150GL30) were applied to the laser induced activation and reacted differently with the diverse structure.

Sun, Jie

2008-01-01

354

Support vector machines for quality monitoring in a plastic injection molding process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Support vector machines (SVMs) are receiving increased attention in different application domains for which neural networks (NNs) have had a prominent role. However, in quality monitoring little attention has been given to this more recent development encompassing a technique with foundations in statistic learning theory. In this paper, we compare C-SVM and ?-SVM classifiers with radial basis function (RBF) NNs in data sets corresponding to product faults in an industrial environment concern...

Ribeiro, Bernardete

2005-01-01

355

Innovative molding technologies for the fabrication of components for microsystems  

Science.gov (United States)

Economic success of microsystems technology requires a wide range of materials as well as the related manufacturing processes. A suitable technology for medium/large scale production is micro injection molding which actually allows the manufacturing of plastic microstructures with 20 microns minimum thickness, structural details of approximately 0.2 microns or maximum aspect ratios of more than 20. These microstructures are, for example, applied as components in micro optics, micro fluidics or minimally invasive surgery. This is demonstrated by microparts that are currently available or will be available soon. For higher economic efficiency and cost reduction, fully electrical injection modeling machines of higher accuracy have been applied. Also, micro insert injection molding reduces mounting costs. Manufacturing of metal or ceramic microparts by powder injection modeling allows large-scale production of complex shaped microstructures with a wide range of materials. Typical examples are sintered structured like stepped LIGA- gear wheels with minimal dimensions of 50 microns in different metal and ceramic materials. Micro Precision Casting originating from conventional investment casting is a suitable process for small/medium-scale production. Examples are microturbine housings made of precious metal alloys. An approach similar to rapid prototyping applies photocurable reactive resins. Photoinduced molding of low viscous resins under ambient conditions leads to significantly reduced cycle times. Additionally, rapid testing of new composite materials can be performed easily. Microcomponents molded from polymers and different composites like dyes with nonlinear optical properties and nanosized ceramic powders will be presented.

Piotter, Volker; Benzler, Tobias; Hanemann, Thomas; Woellmer, Heinz; Ruprecht, Robert; Hausselt, Juergen H.

1999-03-01

356

Effect of powder characteristics on the microstructures and mechanical properties of sintered alloy tool steel compacts by metal injection molding; Kinzoku funmatsu shashutsu seikeiho ni yoru shoketsu gokin koguko no soshiki oyobi kikaiteki seishitsu ni oyonodu funmatsu tokusei no eikyo  

Energy Technology Data Exchange (ETDEWEB)

The effects of powder characteristics on the microstructures and mechanical properties of sintered alloy tool steel (SKD11) compacts by metal injection molding were investigated. A gas-atomized (GA) and a water-atomized (WA) alloy tool steel powders and a polyamide binder were used. They were mixed well and injected into metallic molds for transverse test specimens. These injection-molded specimens were debound at 593 K in air and then were sintered at various temperatures between 1,473 K and 1,483 K in vacuum. These sintered compacts were heated at 1,293 K and quenched, and then were tempered at various temperatures between 453 K and 803 K. The densification of the GA powder compact was fairly superior to that of the WA powder compacts. Consequently, the mechanical properties of the sintered GA powder compacts were superior to those of the sintered WA powder compacts. The mechanical properties equivalent to those of the wrought alloy tool steel could be fabricated successfully by controlling the sintering and heat-treatment conditions precisely. (author)

Nakayama, H. [King invest Co. Ltd., Hiroshima (Japan); Kyogoku, H.; Komatsu, S. [Kinki University, Kyoto (Japan). Faculty of Engineering

2000-12-15

357

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - FY13 Fourth Quarterly Report  

Energy Technology Data Exchange (ETDEWEB)

This quarterly report summarizes the status of the project planning to obtain all the approvals required for a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). The final CRADA documents processed by PNNLs Legal Services were submitted to all the parties for signatures.

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-12-02

358

Fluid Flow Properties of WAG Injection Processes  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Immiscible water-alternating-gas (IWAG) experiments performed on equilibrated fluids are summarised together with the corresponding two-phase gas-oil and water-oil displacements. Experimental studies at reservoir condition and also mechanistic experiments over many years have shown accelerated oil production and higher core flood oil recovery as a result of three-phase flow. The three-phase effects that are included and analysed are; trapped gas, and mobility for secondary processes (ex. wate...

Dale, Elisabeth Iren; Skauge, Arne

2008-01-01

359

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - FY13 Third Quarterly Report  

Energy Technology Data Exchange (ETDEWEB)

This quarterly report summarizes the status for the project planning to obtain all the approvals required for a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). The CRADA documents have been processed by PNNL Legal Services that is also coordinating the revision effort with the industrial parties to address DOEs comments.

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-08-06

360

Process development for the reactive injection moulding of caprolactam intermediates  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to fulfil the need for efficient large volume capable production technologies for high performance composite structures, a new processing technology has been developed. The process is based on the injection moulding technology but differs from this known processing technology by enabling the production of continuous fibre reinforced high performance composites with fibre volume contents of over 40 % by volume. The processing technology enables the processing of very low viscosity pol...

Berg, Lars Fredrik

2011-01-01

 
 
 
 
361

A new mechanism about the process of preparing nanoporous silica with activated carbon mold  

International Nuclear Information System (INIS)

Supercritical fluids can be used to proceed nanoscale casting, during which silica precursor dissolved in supercritical CO2 and the supercritical CO2 was in contact with the active carbon templates. After removal of active carbon templates by calcinations, microporous and mesoporous silica samples replicating not only mesostructures, but also macroscopic of active carbon molds were obtained and the product have better porous capacity and specific surface area. Here, we studied the influences of a variety of factors upon nanoscale casting using supercritical fluids (NC-SCF), and determined the best casting condition. Also, we compared nanoscale casting by using supercritical fluids to simple liquid casting and on the basis of these studies, a new mechanism about preparing nanoporous silica with supercritical CO2-assisted method and with simple liquid casting was proposed

2005-08-15

362

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