WorldWideScience
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Injection molding  

International Nuclear Information System (INIS)

This book deals with injection molding and plastic industry with trend of plastic industry and injection molding like production and consume of plastic in the world, plastic molding such as forming and property process, various molding with shape forming, theories on main molding and the position of injection molding, prospect of injection molding. It also describes property of material on injection molding; introduction, molecule structure, density, crystalizability, transition point, heat condition quality and compressible volume.

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Modelling of the micro injection molding process  

OpenAIRE

Numerical simulation for injection molding has been developed and accepted by the processing industry to improve productivity, part quality and to shorten start-up times. In the particular case of micro injection molding, numerical simulation is all the more crucial since processors deal with much more basic problems than in the case of classical injection molding. Due to the small part dimensions prevailing in micro molding, it is not uncommon to be faced with the total incapacity to achieve...

Gava, Alberto

2008-01-01

3

Metal injection molding process; Metaru injekushon gijutsu  

Energy Technology Data Exchange (ETDEWEB)

The Metal Injection Molding process (MIM) is made up of a process of sintering the formed products at high temperature which are formed by injecting mixture of metal powders and organic powders by a injection forming machine. No defects inside the sintered products produced by the MIM process, good accuracy and low cost of manufacture are the objects of the production technology now. The size error of the MIM may be caused by various reasons, for example, by the difference of the standard management of the metal powders and binders, the difference of mobility of the raw materials in kneading process, the difference of size accuracy owing to the conditions of injection forming, the difference of accuracy of metal mold, the difference of degreasing process and the difference of temperature distribution in sintering process etc. In this paper, the MIM process is introduced and technical objects thereof are summarized from the viewpoint of production technology. The development of binders and degreasing process are the key technology for the MIM process. The representative degreasing methods are classified from the viewpoint of their different principle, and relation of each degreasing method with binders and degreasing conditions are lined up. 7 refs., 7 figs., 2 tabs.

Okamura, K.; Takayama, T. [Komatsu Ltd., Tokyo (Japan). Production Engineering Research Lab.

1996-03-15

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Process and part filling control in micro injection molding  

DEFF Research Database (Denmark)

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

Tosello, Guido; Hansen, Hans NØrgaard

2008-01-01

5

Thermal monitoring of the thermoplastic injection molding process with FBGs  

Science.gov (United States)

Injection molding is an important polymer processing method for manufacturing plastic components. In this work, the thermal monitoring of the thermoplastic injection molding is presented, since temperature is a critical parameter that influences the process features. A set of fiber Bragg gratings were multiplexed, aiming a two dimensional monitoring of the mold. The results allowed to identify the different stages of the thermoplastic molding cycle. Additionally, the data provide information about the heat transfer phenomena, an important issue for the thermoplastic injection sector, and thus for an endless number of applications that employ this type of materials.

Alberto, Nélia J.; Nogueira, Rogério N.; Neto, Victor F.

2014-08-01

6

Injection molding metallic glass  

International Nuclear Information System (INIS)

Advances in alloy development have produced the Zr35Ti30Be27.5Cu7.5 alloy with a crystallization-glass transition temperature, ?T, of 165 deg. C. This alloy's large supercooled liquid region provides the longest processing times and lowest processing viscosities of any metallic glass and was injection molded using tooling based on plastic injection molding technology. Injection-molded beams and die-cast beams were tested in three-point bending. The average modulus of rupture (MOR) was found to be similar, while injection-molded beams had a smaller standard deviation in MOR

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

OpenAIRE

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 par...

Bharti, P. K.; M. I. Khan,; Harbinder Singh

2010-01-01

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

Directory of Open Access Journals (Sweden)

Full Text Available The accurate numerical prediction of the mold filling process of long and thin walled parts is dependent on numerous factors. This paper investigates the effect of various influencing variables on the filling pattern by means of simulation and experimental validation. It was found that mold temperature, process settings and venting conditions have little effect on the predicted filling pattern. However, in the actual case study, the filling behavior observed during the experiments was significantly different compared to the numerical prediction. A structural finite element analysis of the moving mold half showed an unacceptable large deformation of the mold plates under injection pressure. A very good correlation between simulation and experiment was attained after improving the stiffness of the mold. Therefore it can be concluded, that the elasticity of the mold may have a significant influence on the filling pattern when long and thin walled products are considered. Furthermore, it was shown, that even an apparently stiff mold can exhibit a distinct deformation during filling and packing stage.

Stefan Kleindel

2014-03-01

9

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

DEFF Research Database (Denmark)

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

ArlØ, Uffe Rolf; Hansen, Hans NØrgaard

2003-01-01

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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

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Injection molding metallic glass  

Energy Technology Data Exchange (ETDEWEB)

Advances in alloy development have produced the Zr{sub 35}Ti{sub 30}Be{sub 27.5}Cu{sub 7.5} alloy with a crystallization-glass transition temperature, {delta}T, of 165 deg. C. This alloy's large supercooled liquid region provides the longest processing times and lowest processing viscosities of any metallic glass and was injection molded using tooling based on plastic injection molding technology. Injection-molded beams and die-cast beams were tested in three-point bending. The average modulus of rupture (MOR) was found to be similar, while injection-molded beams had a smaller standard deviation in MOR.

Wiest, Aaron [California Institute of Technology, Division of Engineering and Applied Science, 1200 East California Blvd., Pasadena, CA 91125 (United States)], E-mail: aaronwiest@alumni.caltech.edu; Harmon, John S.; Demetriou, Marios D.; Dale Conner, R.; Johnson, William L. [California Institute of Technology, Division of Engineering and Applied Science, 1200 East California Blvd., Pasadena, CA 91125 (United States)

2009-02-15

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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

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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

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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 Taguchi’s parameter design method to determine optimal process parameter settings for PIM. However, these methods are unsuitable in present PIM because of the increasing complexity of product design and the requirement of multi-response quality characteristics. This article aims to review the recent research in designing and determining process parameters of injection molding. A number of research works based on various approaches have been performed in the domain of the parameter setting for injection molding. These approaches, including mathematical models, Taguchi method, Artificial Neural Networks (ANN,Fuzzy logic, Case Based Reasoning (CBR, Genetic Algorithms (GA, Finite Element Method(FEM,Non Linear Modeling, Response Surface Methodology, Linear Regression Analysis ,Grey Rational Analysis and Principle Component Analysis (PCA are described in this article. The strength and theweakness of individual approaches are discussed. It is then followed by conclusions and discussions of the potential research in determining process parameters for injection molding.

P.K. Bharti

2010-09-01

15

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

OpenAIRE

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

Stefan Kleindel; Roland Eder; Herwig Schretter; Christoph Hochenauer

2014-01-01

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Study on the low energy & pollution manufacturing of micro cutting tools by powder injection molding process  

Science.gov (United States)

In this paper, micro cutting tools were manufactured by the powder injection molding process. Most of cutting tools are manufactured by bulk-molding and grinding methods but, the fabrication of micro cutting tools is very difficult because of their minute flute shapes and cutting edges. Therefore, a powder injection molding (PIM) process was used to fabricate the green part of a micro cutting tool with zirconia mixer feedstock and the de-binding and sintering processes were performed. Besides, the grinding processes can be dropped by PIM. Finally, the micro cutting experiment using the newly manufactured tool by PIM was executed for verifying the utility of manufactured tool.

Heo, Young-Moo; Kim, Gun-Hee; Chang, Sung-Ho; Lee, Geun-An

2012-08-01

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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)

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OPTIMIZATION OF PROCESS PARAMETERS THROUGH INJECTION MOLDING CONTROL USING INTELLIGENT METHODS  

OpenAIRE

This doctoral dissertation presents a method for optimizing process parameters in the injection molding process of thermoplastic materials, which is implemented in the developed intelligent system ?C-3. The proposed method is based on a combined approach containing three methods of artificial intelligence where all the rules and facts, conquered during massive experimental tests on two injection molding machines, are implemented within the knowledge base as well as in the database, and are a...

Kusic?, Dragan

2014-01-01

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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)

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Interpretation for the Pressure and Temperature Signals of Injection Molding Process  

Directory of Open Access Journals (Sweden)

Full Text Available An apparatus was developed to acquire temperature and pressure data from the injection molding process. There were three collecting points along the flow path which were allocated at the entrance to the nozzle, near the cavity gate and at the cavity end. Values and plots of temperature and pressure signals were interpreted. Firstly, each acquired signal was detailed introduced, and the characteristic points and segments of the signal plot were explained. Furthermore, comparison of process information which was introduced by one single was made among all of the acquired signals. The practical analysis shows that the pressure signal near the cavity gate is the most effective to describe the status of the sample melt during the injection molding process. But it has the significant delay of indicating the beginning of the cavity filling. With the explanation of signals, the injection molding experiments on the self-developed apparatus can be used to study the processing parameters of sample material.

Yugang Huang

2013-04-01

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Injection Molding of High Aspect Ratio Nanostructures  

DEFF Research Database (Denmark)

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

Matschuk, Maria; Larsen, Niels Bent

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Injection Molding of High Aspect Ratio Nanostructures  

OpenAIRE

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

Matschuk, Maria; Larsen, Niels Bent

2011-01-01

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Injection molding of Y-TZP powders prepared by colloidal processing  

International Nuclear Information System (INIS)

TZP powders containing 3mol% Y2O3 were prepared from ZrOCl2 solution via an aqueous colloidal suspension of ZrO2. Processing variables were optimized to obtain powders suitable for injection molding. Wettability of powders with binders, fluidity of melting compound, removal of binder from green body, and properties of sintered body were investigated

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Injection Molding of Plastics from Agricultural Materials  

Energy Technology Data Exchange (ETDEWEB)

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

Bhattacharya, M.; Ruan, R.

2001-02-22

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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

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On Optimization of Injection Molding Cooling  

OpenAIRE

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

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Determination of injection molding process windows for optical lenses using response surface methodology.  

Science.gov (United States)

This study focuses on injection molding process window determination for obtaining optimal imaging optical properties, astigmatism, coma, and spherical aberration using plastic lenses. The Taguchi experimental method was first used to identify the optimized combination of parameters and significant factors affecting the imaging optical properties of the lens. Full factorial experiments were then implemented based on the significant factors to build the response surface models. The injection molding process windows for lenses with optimized optical properties were determined based on the surface models, and confirmation experiments were performed to verify their validity. The results indicated that the significant factors affecting the optical properties of lenses are mold temperature, melt temperature, and cooling time. According to experimental data for the significant factors, the oblique ovals for different optical properties on the injection molding process windows based on melt temperature and cooling time can be obtained using the curve fitting approach. The confirmation experiments revealed that the average errors for astigmatism, coma, and spherical aberration are 3.44%, 5.62%, and 5.69%, respectively. The results indicated that the process windows proposed are highly reliable. PMID:25321095

Tsai, Kuo-Ming; Wang, He-Yi

2014-08-20

28

Powder injection molding of niobium  

International Nuclear Information System (INIS)

Niobium and niobium-based alloys are used in a variety of high temperature applications ranging from light bulbs to rocket engines. Niobium has excellent formability and the lowest specific weight among refractory metals (Nb, Ta, Mo, W, and Re). Powder injection molding of niobium powder was investigated for efficiency of the process. The sintering of injection molded bars was conducted up to 2000 C in vacuum and low oxygen partial pressure atmosphere. This paper investigates the effect of sintering time, temperature and atmosphere on processing of pure niobium. (orig.)

29

Injection molding ceramics to high green densities  

Science.gov (United States)

The injection molding behavior of a concentrated suspension of Si powder in wax was studied. It was found that the injection molding behavior was a function of the processing techniques used to generate the powder. Dry ball-milled powders had the best molding behavior, while air classified and impact-milled powders demonstrated poorer injection moldability. The relative viscosity of these molding batches was studied as a function of powder properties: distribution shape, surface area, packing density, and particle morphology. The experimental behavior, in all cases, followed existing theories. The relative viscosity of an injection molding composition composed of dry ball-milled powders could be expressed using Farris' relation.

Mangels, J. A.; Williams, R. M.

1983-01-01

30

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; Kübler, Michael; Deckert, Matthias; Bleesen, Christoph

2011-02-01

31

Two component tungsten powder injection molding - An effective mass production process  

Science.gov (United States)

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

Antusch, Steffen; Commin, Lorelei; Mueller, Marcus; Piotter, Volker; Weingaertner, Tobias

2014-04-01

32

Effect of injection molding processing conditions on optical properties of polyetherimide  

Science.gov (United States)

SABIC's ULTEMTM (polyetherimide) resin has been the choice of material for injection moldable micro lenses and lens arrays in optical communication components such as transceivers due to its unique combination of physical, thermal and optical properties including high refractive index, low absorption in near IR range, good dimensional stability and high heat performance. It's known that processing conditions affect properties of final parts. Often the processing conditions are optimized for best mechanical properties, while their effect on optical properties is sidelined. In this study, the effect of injection molding processing conditions on optical properties of polyetherimide resin is discussed.

Zhao, Wei; Wall, Christopher; Maddikeri, Raghavendra; May, Andy

2014-09-01

33

Progress in Titanium Metal Powder Injection Molding  

OpenAIRE

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

34

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

35

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

International Nuclear Information System (INIS)

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

36

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

OpenAIRE

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)...

Kwangho Shin; Youngmoo Heo; Hyungpil Park; Sungho Chang; Byungohk Rhee

2013-01-01

37

Numerical simulation of powder volume fraction variation during powder injection molding filling flow process  

OpenAIRE

The variation of powder volume fraction during powder injection molding filling flow process was simulated based on the two-fluid model. The region in which the serious separation between powders and binder occurs was visually observed in the three-dimensional distribution graph, and the industrial CT was used to verify the results. The results indicate that the simulating variation of powder volume fraction can be obtained with this method. The serious separation between powders and binder o...

Fang, W.; He, X-b; Zhang, R-j; Zhang, S-z; Qu, X-h

2013-01-01

38

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

39

The development of an injection-molding process for a polyanhydride implant containing gentamicin sulfate.  

Science.gov (United States)

A production-scale manufacturing process has been developed for polyanhydride/gentamicin sulfate implants for the treatment of osteomyelitis. Gentamicin sulfate was first dried to an acceptable moisture level by using a tumble vacuum dryer. Dried gentamicin sulfate powder and polyanhydride granules were separately fed into the twin-screw extruder at a pre-determined metering rate using a gravimetric feeding device. The extruded molten mixture was solidified to form strands which were subsequently cut into pellets by using a pelletizer. The pellets were characterized with respect to copolymer molecular weight and drug content uniformity. The pellets were later fed into production-scale injection-molding equipment for implant fabrication. The injection-molding cycle was developed and evaluated in terms of cycle reproducibility. Implants were tested and shown to yield an oriented skin-core structure exhibiting a desirable in-vitro drug release profile. PMID:11977406

Deng, Jone-Shin; Meisters, Marts; Li, Luk; Setesak, Jeff; Claycomb, Lee; Tian, Youqin; Stephens, Dennis; Widman, Matt

2002-01-01

40

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

Directory of Open Access Journals (Sweden)

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

Mohammad Aashiq M1 , Arun A.P1 ,Parthiban M

2013-04-01

41

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

42

Injection molding of metal powders  

International Nuclear Information System (INIS)

The powder Injection Moulding (PIM) process is a viable and competitive commercial technique for producing complex-shaped parts of various materials in high volumes. PIM based on a new binder system and using a Co-Cr-Mo alloy powder as a test material, has been described. The binder comprises a major fraction of polyethylene glycols (PEGs) of various molecular weights and a minor fraction of very finely dispersed poly methyl methacrylate (PMMA) incorporated in the form of an emulsion. Various processing stages of the PIM process, i.e., feedstock preparation, injection molding, de binding and sintering have been discussed. (author)

43

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-05-15

44

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

45

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

DEFF Research Database (Denmark)

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

Tosello, Guido; Gava, Alberto

2007-01-01

46

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

International Nuclear Information System (INIS)

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

47

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

Science.gov (United States)

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

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

48

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 µm and 10 µm 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 µm powder was higher than that of the as-sintered compact of 10 µm powder. In case of the as-sintered compact of 5 µm 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 µm powder, the tensile strength was rather lower than that of the as-sintered compact of 5 µm powder because of coarsening of the grain size. The tensile strength and elongation of the heat-treated compact of 5 µm powder were 1800 MPa and 12 %, respectively. The tensile strength and elongation of the heat-treated compact of 10 µm 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

49

Polyamide 6 - long glass fiber injection moldings  

OpenAIRE

The injection molding ability of long glass fiber reinforced polyamide pellets was studied. The injection moldable materials were produced by a melt impregnation process of continuous fiber rovings. The rovings were chopped to pellets of 9 mm length. Chopped pellets with a variation in the degree of impregnation and fiber concentration were studied. The injection molded samples were analyzed for fiber concentration, fiber length, and fiber orientation. Dumbbell-shaped tensile bars were made t...

Bijsterbosch, H.; Gaymans, R. J.

1995-01-01

50

Injection molded superhydrophobic surfaces based on microlithography and black silicon processing  

DEFF Research Database (Denmark)

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

SØgaard, Emil; Andersen, Nis Korsgaard

2012-01-01

51

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

Theilade, Uffe ArlØ; Hansen, Hans NØrgaard

2006-01-01

52

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.

Østergaard, Peter Friis; Matteucci, Marco

2012-01-01

53

Dynamic of taking out molding parts at injection molding  

OpenAIRE

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

Ragan, E.; Dobra?nsky, J.; Baron, P.; Koc?is?ko, M.; Svetli?k, J.

2012-01-01

54

Process and mold for molding foamed plastic articles  

International Nuclear Information System (INIS)

A method for forming foamed plastic articles which includes the steps of closing a mold; prepressurizing the mold cavity with gas to prevent premature diffusion of blowing gas from the material injected into the cavity; injecting a short shot of molten synthetic resin material containing a blowing agent into the cavity; venting a portion of the prepressurization gas during the injection step; and venting the remaining prepressurization gas from the mold cavity to a vacuum chamber means to allow expansion of the injected foamable resin material within the mold cavity, the vacuum drawing the resin material throughout the mold cavity. In addition, the vacuum chamber is coupled to the mold cavity through plural spaced passageways so that the vacuum is drawn at various locations throughout the cavity to thereby enhance the complete filling of the cavity with the injected material as it expands. The mold is vented following the injection step automatically at the expiration of a predetermined time following the closing of a nozzle of the injection apparatus. A mold for carrying out the process includes improved gas flow means for delivering gas to and venting gas from the mold cavity. The mold also includes improved sealing means for sealing the mold to maintain it in a pressurized state as desired

55

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

56

Orientation distribution and process modeling of thermotropic liquid crystalline copolyester (TLCP) injection-moldings  

Science.gov (United States)

The influence of melt processing conditions upon mechanical properties and degrees of compound molecular orientation have been thoroughly studied for a series of well-defined injection molded samples fabricated from VECTRA (TM) A950 and 4,4'-dihydroxy-a-methylstilbene TLCPs. Fracture and tensile data were correlated with processing conditions, orientation, and molecular weight. Mechanical properties for both TLCPs were found to follow a ``universal'' Anisotropy Factor (AF) associated with the bimodal orientation states in the plaques determined from 2-D WAXS. Surface orientations were globally surveyed using Attenuated Total Reflectance -- Fourier Transform Infrared (ATR-FTIR) spectroscopy and C K edge Near-Edge X-ray Absorption Fine Structure (NEXAFS). The results derived from the two spectroscopy techniques confirmed each other well. These results along with those from 2-D WAXS in transmission were compared with the results of process modeling using a commercial program, MOLDFLOW(TM). The agreement between model predictions and the measured orientation states was gratifyingly good.

Bubeck, Robert; Fang, Jun; Burghardt, Wesley; Burgard, Susan; Fischer, Daniel

2009-03-01

57

Dynamic Feed Control For Injection Molding  

Science.gov (United States)

The invention provides methods and apparatus in which mold material flows through a gate into a mold cavity that defines the shape of a desired part. An adjustable valve is provided that is operable to change dynamically the effective size of the gate to control the flow of mold material through the gate. The valve is adjustable while the mold material is flowing through the gate into the mold cavity. A sensor is provided for sensing a process condition while the part is being molded. During molding, the valve is adjusted based at least in part on information from the sensor. In the preferred embodiment, the adjustable valve is controlled by a digital computer, which includes circuitry for acquiring data from the sensor, processing circuitry for computing a desired position of the valve based on the data from the sensor and a control data file containing target process conditions, and control circuitry for generating signals to control a valve driver to adjust the position of the valve. More complex embodiments include a plurality of gates, sensors, and controllable valves. Each valve is individually controllable so that process conditions corresponding to each gate can be adjusted independently. This allows for great flexibility in the control of injection molding to produce complex, high-quality parts.

Kazmer, David O. (San Francisco, CA)

1996-09-17

58

Finger-powered microfluidic systems using multilayer soft lithography and injection molding processes.  

Science.gov (United States)

Point-of-care (POC) and disposable biomedical applications demand low-power microfluidic systems with pumping components that provide controlled pressure sources. Unfortunately, external pumps have hindered the implementation of such microfluidic systems due to limitations associated with portability and power requirements. Here, we propose and demonstrate a 'finger-powered' integrated pumping system as a modular element to provide pressure head for a variety of advanced microfluidic applications, including finger-powered on-chip microdroplet generation. By utilizing a human finger for the actuation force, electrical power sources that are typically needed to generate pressure head were obviated. Passive fluidic diodes were designed and implemented to enable distinct fluids from multiple inlet ports to be pumped using a single actuation source. Both multilayer soft lithography and injection molding processes were investigated for device fabrication and performance. Experimental results revealed that the pressure head generated from a human finger could be tuned based on the geometric characteristics of the pumping system, with a maximum observed pressure of 7.6 ± 0.1 kPa. In addition to the delivery of multiple, distinct fluids into microfluidic channels, we also employed the finger-powered pumping system to achieve the rapid formation of both water-in-oil droplets (106.9 ± 4.3 ?m in diameter) and oil-in-water droplets (75.3 ± 12.6 ?m in diameter) as well as the encapsulation of endothelial cells in droplets without using any external or electrical controllers. PMID:25102160

Iwai, Kosuke; Shih, Kuan Cheng; Lin, Xiao; Brubaker, Thomas A; Sochol, Ryan D; Lin, Liwei

2014-10-01

59

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

CERN Document Server

The plastic injection mold manufacturing process includes polishing operations when surface roughness is critical or mirror effect is required to produce transparent parts. This polishing operation is mainly carried out manually by skilled workers of subcontractor companies. In this paper, we propose an automatic polishing technique on a 5-axis milling center in order to use the same means of production from machining to polishing and reduce the costs. We develop special algorithms to compute 5-axis cutter locations on free-form cavities in order to imitate the skills of the workers. These are based on both filling curves and trochoidal curves. The polishing force is ensured by the compliance of the passive tool itself and set-up by calibration between displacement and force based on a force sensor. The compliance of the tool helps to avoid kinematical error effects on the part during 5-axis tool movements. The effectiveness of the method in terms of the surface roughness quality and the simplicity of impleme...

Pessoles, Xavier; 10.1016/j.jmatprotec.2008.08.034

2010-01-01

60

Dynamic of taking out molding parts at injection molding  

Directory of Open Access Journals (Sweden)

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

E. Ragan

2012-10-01

61

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

62

Simulation and Design of a plastic injection mold  

OpenAIRE

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

63

Injection molding of silicon nitride  

International Nuclear Information System (INIS)

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

64

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

65

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.

Al-Azawi, A.; Smistrup, Kristian

2014-01-01

66

Injection molding and debinding of micro gears fabricated by micro powder injection molding  

Science.gov (United States)

Micro powder injection molding (?PIM) was investigated for possible mass production of micro-components at relatively low cost. However, scaling down to such a level produces challenges in injection molding and debinding. Micro gears were fabricated by ?PIM from in-house feedstock. The effect of injection speed and injection pressure on the replication of the micro gear cavity was investigated. Solvent debinding and thermal debinding processes were discussed. The results show that micro gears can be successfully fabricated under the injection pressure of 70 MPa and the 60% injection speed. Either too low or too high injection speed can cause incomplete filling of micro gears. The same is the case with too low injection pressure. Too high injection pressure can bring cracks. Solvent debinding of micro gears was performed in a mixture of petroleum ether and ethanol. Subsequently, micro gears were successfully debound by a multistep heating schedule.

Ni, Xin-lei; Yin, Hai-qing; Liu, Lin; Yi, Shan-jie; Qu, Xuan-hui

2013-01-01

67

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

68

Mold  

International Nuclear Information System (INIS)

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

69

Validation of three-dimensional micro injection molding simulation accuracy  

DEFF Research Database (Denmark)

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

Tosello, Guido Technical University of Denmark,

2011-01-01

70

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

International Nuclear Information System (INIS)

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

71

Injection molding of high aspect ratio sub-100 nm nanostructures  

DEFF Research Database (Denmark)

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

2013-01-01

72

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

73

OPTIMIZATION OF THE INJECTION PROCESS FOR A PLATE PART USING MOLD FLOW SOFT  

Directory of Open Access Journals (Sweden)

Full Text Available Many times, in practice, the preparation of the injection process for new parts is time consuming. Using injection simulation software, we can reduce the time interval required for settings, the loss of material etc., thus optimizing the entire procedure. The studied part was made within a company from Bihor County and the problem was that the part broke when the mould opened (as in figure below.

Flavius A. Ardelean

2009-11-01

74

Analysis of optical properties in injection-molded and compression-molded optical lenses.  

Science.gov (United States)

Numerical mold-flow simulations and experimental measurements for injection-molded lenses have been investigated in form accuracy on a two-cavity mold with various process conditions. First, form profiles of the molded lenses have been measured together with the corresponding simulated mold-temperature distribution and displacement distribution of the lens in the z direction. A flow-through type layout of cooling channels has been devised for balance of mold-temperature distribution in mold cavities with various parametric distances for assessments in uniformity of temperature distribution. Finally, a compression-molding process is proposed for the post-process of birefringence relaxation as well as adequate form accuracy of lenses. In conclusion, optimization of process parameters to achieve good form accuracy in a multicavity mold with symmetric geometry but nonuniform cooling conditions is difficult. A good design of cooling channels plus optimized process conditions could provide uniform mold-temperature distribution so that molded lenses of good quality would be possible. Then, the profile deviation of lenses could be further compensated by profile geometry corrections. In conclusion, the post-compression-molding process could make birefringence-free plastic lenses with good form accuracy. PMID:24787426

Wang, Chung Yen; Wang, Pei Jen

2014-04-10

75

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

OpenAIRE

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 ...

Rani, A. M. A.; Raghavan, V. R.; Altaf, K.

2011-01-01

76

Mechanical properties of AM-series magnesium alloy made by injection molding process; Shashutsu seikeiho ni yori sakuseishita AM kei magnesium gokin no kikaiteki seishitsu  

Energy Technology Data Exchange (ETDEWEB)

Discussions were given on mechanical properties of AM-series magnesium alloy made by injection molding process. In the discussions, tensile test pieces of the AM-series magnesium alloys (AM50A and AM60B) were formed by the injection molding process to investigate effects of different molding conditions on their mechanical properties in relation with microstructures. The experiment had the mold temperature setting kept constant at 443K, and the barrel temperature and injection velocity varied. For the microstructures, observations using an optical microscope were performed on cross section in the vicinity of test piece fracture section after polishing and etching. The following findings were obtained as a result of the discussions: rise in the barrel temperature reduces solid phase rate and improves the mechanical properties, but the properties saturate above the melting point; increased injection velocity reduces average grain size in the liquid phase, and improves the mechanical properties; and the AM-series alloy forms made by the injection molding process have finer microstructures and show better mechanical properties than die-cast materials. 10 refs., 9 figs., 2 tabs.

Tsukeda, T.; Saito, K. [The Japan Steel Works, Ltd., Tokyo (Japan)

1998-10-25

77

Powder Injection Molding of Ceramic Engine Components for Transportation  

Science.gov (United States)

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

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

2012-03-01

78

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.

79

Use of alternative materials for injection molding prototyping tools  

OpenAIRE

Thesis shows the design of a prototype tool for injection molding in an unconventional way. The process of design is adapted to the manufacturing technology by selective laser sintering of alumide. A product from the real industrial environment is selected.With injection molding simulations, the deformation of the base model is shown. On the basis of these the solution, that involves changes in the product geometry and tool design with conformal cooling channels, is based. Simulation of injec...

Salobir, Andrej

2013-01-01

80

Preparation and Characterization of Copper Feedstock for Metal Injection Molding  

OpenAIRE

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...

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

2010-01-01

81

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,

82

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

83

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

84

Injection molding of zirconia oxygen sensor thimbles by an aqueous process  

International Nuclear Information System (INIS)

This patent describes a method of forming the ceramic element in a zirconia oxygen sensor. It comprises: forming a mixture. It comprises: ZrO2 and a stabilizer selected from the element group consisting of oxides of Y, Ce, Mg, Ca and mixtures thereof and having an average particle size less than or equal to 1 micron; an agaroid gel-forming material having a gel strength, measured at a temperature between 0 degrees C and about 22 degrees C on a gel consisting essentially of about 4 wt % of the gel-forming material and water, of at least about 100 g/cm2; a gel-forming material solvent; and molding the mixture at a temperature sufficient to produce the ceramic element; and sintering the ceramic element at an elevated temperature to a density of at least 5.5 g/cm3

85

A Recurrent Neural Network for Warpage Prediction in Injection Molding  

OpenAIRE

Injection molding is classified as one of the most flexible and economical manufacturing processes with high volumeof plastic molded parts. Causes of variations in the process are related to the vast number of factors acting during aregular production run, which directly impacts the quality of final products. A common quality trouble in finishedproducts is the presence of warpage. Thus, this study aimed to design a system based on recurrent neural networksto predict warpage defects in product...

Alvarado-iniesta, A.; Valles-rosales, D. J.; Garci?a-alcaraz, J. L.; Maldonado-macias, A.

2012-01-01

86

Structural development of HDPE in injection molding  

OpenAIRE

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...

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

2003-01-01

87

Binder Removal from Powder Injection Molded 316L Stainless Steel  

OpenAIRE

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 ...

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

2011-01-01

88

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

OpenAIRE

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 30°C, 50°C, 80°C, 100°C, 120°C, 150°C, 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

89

Two component micro injection molding for MID fabrication  

OpenAIRE

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 Nørgaard; Tang, Peter Torben

2009-01-01

90

Injection molding of TiAl alloyed powder  

Science.gov (United States)

To realize manufacturing process of near net shape, titanium aluminide powder injection molding was applied to TiAl alloyed powder. TiAl alloyed powder was mixed with the binder consisting of wax and acrylic resin at the content of 45 vol pct. Flow characteristics of this compound was evaluated by extrusion-type flow meter. Then it was injection-molded to the shape of a tensile test pieces. These test pieces were debinded in various atomospheres and sintered in vacuum. Sintered TiAl manufactured by this process was examined for its microstructure and mechanical properties. The potential and problems of this process are discussed.

Kato, Kiyotaka; Nozaki, Yoshihiko

91

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

92

Stability of FDTS monolayer coating on aluminum injection molding tools  

DEFF Research Database (Denmark)

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

Cech, Jiri; Taboryski, Rafael J.

2012-01-01

93

The Study of Surface Properties in Injection Moldings (Part-1)  

Science.gov (United States)

Injection molding is used in various fields. Surface properties are an important subject and there are many reports on them. From the viewpoints of cost and productivity, the injection molding of multi-cavity injection die is used widely. However, there is no report on the research of surface properties in these injection moldings. In this study, we observed surface state and measured surface roughness for the injection molding with emboss form on the surface and compared with surface state about molding conditions. Moreover, we carried out the optimization of runner design in consideration of simultaneous filling using injection molding flow analysis and considered the influence of runner balance on the surface state. High mold temperature improves surface properties for the whole injection molding. Short filling time improves surface properties for the portions do not require much packing pressure. The optimized runner balance can realize uniform surface properties in multi cavity injection die.

Kodama, Katsuhiro; Fujiwara, Kensuke; Tange, Akio; Yamashita, Katsuhisa; Nonomura, Chisato; Yokoyama, Atsushi

94

Injection molded polymer optics in the 21st Century  

Science.gov (United States)

Precision polymer optics, manufactured by injection molding techniques, has been a key enabling technology for several decades now. The technology, which can be thought of as a subset of the wider field of precision optics manufacturing, was pioneered in the United States by companies such as Eastman Kodak, US Precision Lens, and Polaroid. In addition to suppliers in the U.S. there are several companies worldwide that design and manufacture precision polymer optics, for example Philips High Tech Plastics in Europe and Fujinon in Japan. Designers who are considering using polymer optics need a fundamental understanding of exactly how the optics are created. This paper will survey the technology and processes that are employed in the successful implementation of a polymer optic solution from a manufacturer's perspective. Special emphasis will be paid to the unique relationship between the molds and the optics that they produce. We will discuss the key elements of production: molding resins, molds and molding equipment, and metrology. Finally we will offer a case study to illustrate just how the optics designer carries a design concept through to production. The underlying theme throughout the discussion of polymer optics is the need for the design team to work closely with an experienced polymer optics manufacturer with a solid track record of success in molded optics. As will be seen shortly, the complex interaction between thermoplastics, molds, and molding machines dictates the need for working closely with a supplier who has the critical knowledge needed to manage all aspects of the program.

Beich, William S.

2005-08-01

95

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

Directory of Open Access Journals (Sweden)

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

Irfan Shirazi M.

2014-07-01

96

Long fiber polymer composite property calculation in injection molding simulation  

Science.gov (United States)

Long fiber filled polymer composite materials have attracted a great attention and usage in recent years. However, the injection and compression molded long fiber composite materials possess complex microstructures that include spatial variations in fiber orientation and length. This paper presents the recent implemented anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model for predicting fiber orientation distribution[1] and a newly developed fiber breakage model[2] for predicting fiber length distribution in injection and compression molding simulation, and Eshelby-Mori-Tanaka model[3,4] with fiber-matrix de-bonding model[5] have been implemented to calculate the long fiber composite property distribution with predicted fiber orientation and fiber length distributions. A validation study on fiber orientation, fiber breakage and mechanical property distributions are given with injection molding process simulation.

Jin, Xiaoshi; Wang, Jin; Han, Sejin

2013-05-01

97

Injection molding of coarse 316L stainless steel powder  

International Nuclear Information System (INIS)

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

98

Injection molding of M2 high speed steel  

International Nuclear Information System (INIS)

The purpose of this work is to study the feasibility of Powder Injection Molding in order to obtain M2 High Speed Steels with higher performances than those obtained by conventional P/M. With this object trials have been carried out in order to optimize all the process steps (mixing,injection, debinding and sintering) and to evaluate the mechanical properties (hardness and transverse tensile strength) of the manufactured M2 HSS sample. (Author) 11 refs

99

Behavior and modeling of injection molded PP  

OpenAIRE

The structural impact laboratory (SIMLab) at NTNU have developed a constitutive material modelto represent the behavior of brittle and ductile polymeric materials. The material model can be implementedinto finite element solvers, e.g. LS-Dyna and Abaqus. In this thesis, the material model?sability to describe the behavior of an injection molded polypropylene, provided by TOYOTA, hasbeen studied.The material had during previous experimental tests shown an inhomogeneous material behavior.A...

Røstum, Heine Havneraas

2014-01-01

100

A Recurrent Neural Network for Warpage Prediction in Injection Molding  

Directory of Open Access Journals (Sweden)

Full Text Available Injection molding is classified as one of the most flexible and economical manufacturing processes with high volumeof plastic molded parts. Causes of variations in the process are related to the vast number of factors acting during aregular production run, which directly impacts the quality of final products. A common quality trouble in finishedproducts is the presence of warpage. Thus, this study aimed to design a system based on recurrent neural networksto predict warpage defects in products manufactured through injection molding. Five process parameters areemployed for being considered to be critical and have a great impact on the warpage of plastic components. Thisstudy used the finite element analysis software Moldflow to simulate the injection molding process to collect data inorder to train and test the recurrent neural network. Recurrent neural networks were used to understand the dynamicsof the process and due to their memorization ability, warpage values might be predicted accurately. Results show thedesigned network works well in prediction tasks, overcoming those predictions generated by feedforward neuralnetworks.

A. Alvarado-Iniesta

2012-11-01

101

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

OpenAIRE

Fiber orientation is a big challenge in short fiber reinforced composites. Powder injection molding (PIM) process has some intrinsic fiber alignment associated with it. During PIM process fibers in skin region of moldings are aligned as these regions experience higher shear flow caused by the mold walls. Fibers in the core region remain randomly aligned as these regions are far from mold walls and experience lesser shear flow. In this study short carbon fiber (CF) reinforced copper matrix com...

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

2014-01-01

102

Microstructural and mechanical characterization of injection molded 718 superalloy powders  

International Nuclear Information System (INIS)

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

103

Stability of FDTS monolayer coating on aluminum injection molding tools  

International Nuclear Information System (INIS)

Highlights: ? We present novel and highly useful results on FDTS monolayer coating of aluminum. ? The coating is particularly applicable for coating of prototyping injection molding tools, which often are made of Al. ? We have demonstrated that the coating prevails in injection molding conditions and that the coating will prevent wear of the tools. - Abstract: 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.

104

Foaming morphology control of microcellular injection molded parts with gas counter pressure and dynamic mold temperature control  

Science.gov (United States)

Microcellular injection molding process is a promising solution for products with special requirements such as weight reduction, extra thin wall, high dimensional stability, clamping force reduction, etc. Despite microcellular foaming application used in reciprocating screw injection molding machine was built more than a decade, some limitations, such as poor surface quality or poor foaming control, confine the usage of this technology. Earlier CAE simulation tool for microcellular injection molding was not successful due to insufficient physical and computational considerations, limited by complicated bubble growth mechanism; so that, an economic and efficient tool for examining foaming quality of injection foaming product was lack. In this study, a recent developed three-dimensional simulation tool is used to predict injection foaming process. Predictions are carried out with commodity polypropylene and polystyrene with nitrogen and carbon dioxide supercritical fluids (SCFs). Comparisons of simulations between microcellular injection molding with and without counter pressure are discussed to provide insights into the correlation of surface quality and cell size distribution near the surface of product. Furthermore, comparisons between simulation predictions and experimental results of molding process, which is featured with dynamic mold temperature and gas counter pressure, are given for understanding quality improvement by controlling foaming morphology, and benefit of industrial application.

Shiu, Tai-Yi; Huang, Chao-Tsai; Chang, Rong-Yu; Hwang, Shyh-Shin

2014-05-01

105

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

Mohd. Afian Omar

2010-01-01

106

Injection molding, debinding and sintering of 316L stainless steel microstructures  

Energy Technology Data Exchange (ETDEWEB)

The micro powder injection molding ({mu}PIM) process was used to fabricate metallic microstructures in this paper. The production of 316L stainless steel microstructures arrays with the dimensions of 100 {mu}m x height200 {mu}mand 60 {mu}m x height 191 {mu}m is presented. Injection molding was conducted on a conventional injection molding machine and silicon mold inserts with vertical sidewall made by deep reactive ion etching (DRIE) were used. Molded parts with microstructures were well obtained after selecting suitable processing parameters based on the feedstock characteristics. Then the molded parts were debound catalytically and sintered. Sintering at different temperature was conducted under vacuum. The effects of sintering temperatures were evaluated based on the polished and etched micrographs of the sintered microstructures. Finally Young's Modulus of sintered microstructure was evaluated using nano-indenter. (orig.)

Fu, G.; Loh, N.H.; Tor, S.B. [Technological University, School of Mechanical and Aerospace Engineering Nanyang, Singapore (Singapore); Tay, B.Y. [Singapore Institute of Manufacturing Technology, Singapore (Singapore); Murakoshi, Y.; Maeda, R. [National Institute of Advanced Industrial Science and Technology (AIST), Advanced Manufacturing Research Institute, Ibaraki (Japan)

2005-08-01

107

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,

108

Packing parameters effect on injection molding of polypropylene nanostructured surfaces  

DEFF Research Database (Denmark)

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

Calaon, Matteo; Tosello, Guido

2012-01-01

109

Weld line morphology of injection molded polypropylene  

Science.gov (United States)

One of the main goals of this research was to develop an understanding of the specific cause(s) of mechanical weakness at weld lines in injection molded plastic parts. In this study, a variety of techniques have been used to evaluate polypropylene weld lines: optical microscopy, electron microscopy, x-ray photoelectron microscopy, Fourier transform infrared spectroscopy and mechanical property measurements. Optical microscopy results showed that the weld line penetrates about 10 microns into the sample, and that the crystalline morphology near the weld line was very different than in the polymer further removed. Transmission electron microscopy was used to determine that the material at the weld line was of slightly different density and stained differently than the rest of the polypropylene material. X-ray photoelectron spectroscopy (XPS) determined that the material at the flow front was enriched in elemental sulfur and oxygen, which helped identify it as an antioxidant additive. Finally, FTIR was used to confirm that the flow front tip was enriched in the antioxidant material by comparing spectra of the neat antioxidant. The data cumulatively demonstrate that a low concentration (additive was accumulating at the flow front surface during mold filling, and was subsequently trapped at the weld line as it was formed. This additive accumulation is responsible in a large part for the weakness observed at the weld line in the polypropylene system studied. Other low concentration additives were also found to accumulate at polypropylene weld lines, also making the interface weak. Even an incompatible, higher surface free energy polymer, polystyrene, when added at low concentration to polypropylene, was found to accumulate at the weld line. Therefore, surface free energy was found not to play a role in these accumulations. Homogeneous elongation was found not to reproduce the enrichments observed. The mechanism by which low concentration additives accumulate at flow fronts is speculated to involve incompatible droplets experiencing a stress gradient due to the elongation gradient at the flow front during fountain flow which "pushes" them out toward the free surface. In addition, large concentrations of the heat stabilizer additive was also observed on the injection molded part surface, probably deposited there by fountain flow of the flow front. This observation could have practical implications for using low concentration additives to achieve surface modification of injection molded parts. Attempts were made to modify part surfaces to improve conductivity and part release from the mold. Unfortunately, the base polypropylene polymer used in these experiments contained low level heat stabilizer additives which masked any surface accumulation measurements of other added materials using XPS. In one instance, a mixture of polypropylene with a low concentration of low molecular weight polystyrene, the intended surface modifier was observed by TEM below a thin layer that was determined by XPS to be heat stabilizer. Obviously, a more controlled study of the surface deposition is necessary before it can be exploited.

Mielewski, Deborah Frances

110

Injection-compression and co-injection moldings of amorphous polymers: Viscoelastic simulation and experiment  

Science.gov (United States)

Injection-compression molding (ICM) and co-injection molding have gained increasing importance in manufacturing of polymer products. Scientific understanding of these processes is presently limited and no attempts have been made to simulate co-injection molding using a viscoelastic model. In addressing this issue, the present study provides results of comprehensive viscoelastic simulations and experimental investigations of the residual stresses and birefringence in center-gated disk moldings of amorphous polymers obtained by ICM and sequential co-injection molding (SCIM) at various processing conditions. The governing equations for viscoelastic simulation of ICM and SCIM processes were derived using a nonlinear viscoelastic model. The equations were solved using a hybrid control volume/finite element/finite difference method. In general, residual stresses and birefringence in moldings arise from the flow- and thermally-induced contributions. To consider the thermal contribution, simulations and experimental study of birefringence in freely quenched multi-layered plates were carried out. The flow- and thermally-induced stresses were simulated using nonlinear and linear viscoelastic theories, respectively. The overall residual birefringence in moldings was obtained by summation of the flow- and thermally-induced birefringence contributions calculated using the stress-optical rule and photoviscoelastic constitutive equation, respectively. The numerical results were found to be in fair agreement with experimental data on the distribution of residual birefringence, Deltan, and average transverse birefringence, , of the ICM made from polycarbonate (PC) and polystyrene (PS). It was found that the melt temperature and compression stroke strongly affected the residual birefringence in ICM, while the mold temperature had less effect. The numerical and experimental results of the gapwise distribution of the residual birefringence, Delta n, and interface of the SCIM were obtained at various processing conditions and various combinations of multi-layers of PC, PS and PMMA. It was found that the melt temperature strongly affected the birefringence and interface distribution, while the mold temperature had less effect. In addition, the interface was strongly affected by the volume of injected skin melt. Numerical results were found to be in a fair agreement with experimental data.

Kim, Nam Hyung

111

Metal injection molding of titanium for medical and aerospace applications  

Science.gov (United States)

Mixing of titanium powder and thermoplastic binders creates a feedstock that is injection molded similar to plastic, has a chemical and thermal debinding process, and then is sintered to form a net-shape or near-net shape part. TiJet Medizintechnik GmbH (TiJet) developed and uses its own feedstock and powder processing technology to achieve desired mechanical properties. This paper explains the theory of the process and the possibilities that result from the development of this new powder processing technology, such as new alloys, design possibilities, etc. Discussed will be the microstructure, chemical composition, and mechanical properties of the manufactured parts.

Scharvogel, Matthias; Winkelmueller, Wendelin

2011-02-01

112

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

113

Integral optical system design of injection molded optics  

Science.gov (United States)

Injection molded optics are frequently applied in many high volume applications. Bar code scanners, CD / DVD systems, CMOS cameras are a few examples. In all of these applications cost effective and fast design cycles are essential. At Philips High Tech Plastics we developed a design system that touches on all different aspects of the system design. Starting with traditional lens design (sequential ray tracing) and tolernacing we transport the initial design into mechanical solid modeling. During mechanical modeling, tolerances, injection molding design rules and integration of mechanical features, reference marks, etc. are incorporated as well. Here the full advantage of injection molding can be utilized. After the opto - mechanical modeling the system is ported back to non - sequential ray tracing for ghost - and stray light analysis. Finally extended tolerancing is performed in order to come to a robust high volume product. If necessary all or several steps in this design process are repeated in order to arrive at the final design. As an additional requirement the metrology possibilities for the design are checked in at an early stage. This integral system approach to optical design, including optical modeling (sequential and non-sequential) combined with mechanical solid modeling is presented using some recent examples.

Baumer, Stefan M.; Shulepova, Lena; Willemse, Jan; Renkema, Kor

2003-11-01

114

Fast prototyping of injection molded polymer microfluidic chips  

DEFF Research Database (Denmark)

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

Hansen, Thomas Steen; Selmeczi, David

2010-01-01

115

Fast prototyping of injection molded polymer microfluidic chips  

International Nuclear Information System (INIS)

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

116

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

117

Analyzing melt homogeneity in a single screw plasticizing unit of an injection molding machine  

Science.gov (United States)

In injection molding investigations on mixing efficiency and thermal homogeneity of the melt in the screw chamber are of great interest as the directly effect the quality of the molded parts. For most injection molding applications mixing is performed in the single screw plasticizing unit of the injection molding machine. In this work, a CFD approach with two coupled fluid domains is used in order to describe the plasticizing process in an injection molding machine. One domain rotates and translates in axial direction (screw), the other one increases its length (chamber). On basis of the calculated pressure, velocity and temperature field of the polymer melt the thermal melt homogeneity is investigated. To analyze the optical-mechanical homogeneity of the melt a Euler-Lagrangian method is used to calculate the distribution of tracer particles within the screw chamber.

Straka, K.; Praher, B.; Steinbichler, G.

2013-10-01

118

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

119

Capabilities Of Micro Powder Injection Molding For Microparts Manufacturing  

Science.gov (United States)

The Micro-PIM processing technology satisfies the increasing demand in terms of smaller parts and miniaturization. Research works in this area have been carried out at FEMTO-ST Institute by performing the injection molding with 316L stainless steel fine powders and polymer binders. Several formulations with different proportion of powders and binders as well various polymers have been tested, and then a well adapted one has been selected. The process to select the well adapted formulation and the rheological characteristics of the feedstock realized according with the selected formulation are also detailed. Several test specimens have been successfully manufactured.

Kong, X.; Barriere, T.; Gelin, J. C.

2011-01-01

120

Molding Properties and Causes of Deterioration of Recycled Powder Injection Molding Feedstock  

Science.gov (United States)

To lower the manufacturing cost of powder injection molded products, the gate, runner, sprue, and green parts with defects are usually recycled. Unfortunately, these feedstocks deteriorate as the number of recycling iterations increases. This study presents an investigation of the molding properties and the causes of the deterioration of the recycled feedstocks by monitoring changes in melting points, in-situ strength changes during solvent debinding, spiral length, and viscosity. The oxygen content measurements indicate that serious oxidation occurs after recycling, particularly in the paraffin wax (PW). The results of the molecular weight from gel-permeation chromatography (GPC) also show that the polyethylene (PE) deteriorates during recycling. The viscosity of the 1R (recycled once) feedstock was slightly lower than that of the fresh material. However, as the number of recycling iterations increased, the viscosity increased again. As a result, the spiral length decreased and the required injection pressure increased. It was also noticed that more defects developed along the molding and debinding process.

Cheng, L. H.; Hwang, K. S.; Fan, Y. L.

2009-12-01

121

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

122

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

Scientific Electronic Library Online (English)

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

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

2004-03-01

123

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

Directory of Open Access Journals (Sweden)

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

Beal V. E.

2004-01-01

124

Investigation of Properties of Powder Injection-Molded Steatites  

Science.gov (United States)

In this study, the mechanical and micro-structural properties of injection-molded steatites were investigated experimentally. Initially, steatite powders and binders of polyethylene glycol (PEG), polypropylene (PP), and stearic aside (SA) were mixed to prepare the feedstock. The mixing powders were granulated using the extruder. The short granules in cylindrical shapes were used as the feedstock in the injection-molding operations. Solvent- and thermal-debinding processes were applied to the green samples after the molding. The samples were sintered at 1300 °C for 4 h, and a theoretical density of 98-99% was achieved. Three-point bending and tensile tests were performed on the samples which were sintered at 1200-1300 °C. The maximum three-point bending and tensile strength values were found as 154 and 47 MPa, respectively. The morphology of fractured surface was done by scanning electron microscopy whereas porosity investigations were carried out using the same microscopy. Grain growth and structure on the specimens were also investigated using transmission electron microscopy.

Urtekin, L.; Uslan, I.; Tuc, B.

2012-03-01

125

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

OpenAIRE

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

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

2003-01-01

126

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

Directory of Open Access Journals (Sweden)

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

Edwin V. Cardoza Galdamez

2004-04-01

127

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

Science.gov (United States)

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

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

2009-12-01

128

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

OpenAIRE

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...

Norhamidi Muhamad; Muhamad Hussain Ismail; Mohd Afian Omar

2008-01-01

129

FPGA-Based Multiprocessor System for Injection Molding Control  

OpenAIRE

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...

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

2012-01-01

130

New Design and Injection Molding Analysis of a Low Smoke Zero Halogen Cable Trunk  

Directory of Open Access Journals (Sweden)

Full Text Available The traditional production process of a cable trunk is plastic extrusion with PVC or other halogen containing materials. However, they have many disadvantages such as easy burning, producing toxic gases and smokes. A low smoke zero halogen (LSZH cable trunk was designed and developed in the present study and the injection molding process was adopted to produce the LSZH cable trunk. Numerical simulations were applied to investigate the effects of the important process parameters on the warpage of the cable trunk. Comparing the simulation results under different process conditions and consideration both of the volumetric shrinkage and the total warpage displacement, it is found that the process parameters, including mold temperature 75°C, melt temperature 265°C, injection pressure 190 MPa, packing pressure 152 MPa, cooling water temperature 50°C and injection time 3 s, are the optimal process conditions for the injection molding process of the new designed cable trunk.

Xiaoxun Zhang

2012-09-01

131

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

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

2012-12-01

132

Residual stress distribution in injection molded parts  

OpenAIRE

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

Postawa, P.; Kwiatkowski, D.

2006-01-01

133

Injection molded dielectromagnets prepared from mixture of hard magnetic powders  

International Nuclear Information System (INIS)

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

134

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

135

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)

136

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

137

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)

138

Development of craniofacial implants produced by metal injection molding of titanium alloy using novel binder system based on palm oil  

OpenAIRE

Metal Injection Molding (MIM) is a cost-effective technique for producing small, complex, precision parts in high volumes. MIM consists of four main processing steps: mixing, injection molding, debinding and sintering. In the mixing step, the powder titanium alloy (Ti6Al4V) medical grade is mixed with a binder system based on palm stearin to form a homogeneous feedstock. The rheological studies of the feedstock have been determined properly in order to success during injection into injection ...

Ibrahim, R.; Azmirruddin, M.; Jabir, M.; Ridhuan, M.; Muhamad, M.; Rafiq, M.; Abu Kasim, N. H.; Muhamad, S.

2010-01-01

139

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.

140

A Simulation Study of Conformal Cooling Channels in Plastic Injection Molding  

OpenAIRE

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

Omar A Mohamed, S. H. Masood

2013-01-01

141

Multiple Performance Optimization for the Best Metal Injection Molding Green Compact  

OpenAIRE

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) Injec...

Harun, M. R.; Nor, N. H. M.; Ibrahim, M. H. I.; Ahmad, S.; Ab Rahman, M. N.; Muhamad, N.; Jamaludin, K. R.; Daud, M. Y. M.

2011-01-01

142

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

DEFF Research Database (Denmark)

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

Islam, Aminul; Giannekas, Nikolaos

2014-01-01

143

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)

144

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

145

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

Science.gov (United States)

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

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

2013-04-01

146

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

Science.gov (United States)

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

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

2013-08-20

147

Injection molding of power-law polymer  

Science.gov (United States)

A polymer in injected with a constant pressure gradient between two parallel plates. The progression of the polymer front is modeled for a power law fluid (typical of a polymer) and compared to results for a Newtonian fluid.

Krane, Matthew J. M.

2008-10-25

148

Development and application of FINEMOLD. ; Powder metallurgy precision parts by injection molding. FINEMOLD no tenkai to oyo. ; Shashutsu seikei funmatsu yakin seimitsu buhin  

Energy Technology Data Exchange (ETDEWEB)

FINEMOLD is a trade name, given to powder metallurgy precision parts, produced by Nippon Seisen from metallic micropowder by an injection molding method. That company technically introduced the process from the USA in 1985 and entered the field of powder metallurgy by the injection molding. The production process of FINEMOLD proceeds in order of metallic powder kneading with binder, pelletizing, composing, injection molding, debinding, sintering and post-machining. The present production is, to the utmost, premised to be free from post-machining. However. parts unavoidably needing post-machining are to undergo sizing. That productio is maximally characterized by molding, entirely identical in method with that of plastics by use of injection molding machine. To specify the mold design, it is required to give instructions, specific to the injection molding, while the metallic micropowder is pricewise very expensive. Those points of problem must be engineered to be mitigated. 5 figs., 2 tabs.

Hattori, M. (Nihon Seisen Co. Ltd., Osaka (Japan))

1991-06-05

149

Influence of Mold Surface Treatments on Flow of Polymer in Injection Moulding. Application to Weldlines  

Science.gov (United States)

Due to increasing expectations from the market, the aspect of molded parts has to be improved constantly. Some of the defects observed on these parts such as weldlines are related to the filling stage. To limit this, we investigated the influence on weldlines using various surface deposits on the mold surface, mainly PVD and PACVD deposits : Chromium nitride (CrN), Titanium nitride (TiN), Diamond like Carbon (DLC), Chromium and polished steel (PG) on an instrumented plate mold. Injection campaign was led on three polymers which differ in terms of nature (amorphous, semi-crystalline, copolymers). We studied the evolution of the dimensions of weldlines appearing on the plate using the same injection parameters for a given polymer, but with various deposits and thicknesses. Another aspect that had been investigated is the morphology of the weldline through the thickness of the part, depending on polymer nature. Adhesion of polymer at the flow front with the mold surface proved to change. The modification of the initial contact in the filling stage and thus the thermal resistance at the mold implied a change in the process, increasing or reducing the pressure loss in the flow and differential shrinkage in the final part. The induced impact on dimensions of the weldlines allowed to distinguish which surface treatments were able to reduce the defect. A complementary study was led on both polymers in molten state and deposits in terms of wetting using a sessile drop method to confirm the adhesion at the polymer/mold interface. This study proved the influence of the use of surface treatments has clearly an impact on the filling stage of the injection molding process, and it is necessary to get a better knowledge of the interactions between physical adhesion, tribology of polymer/mold contact, and thermal properties of the coatings and their impact on solidification of the polymer.

Chailly, M.; Charmeau, J.-Y.; Bereaux, Y.; Monasse, B.

2007-04-01

150

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

International Nuclear Information System (INIS)

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

151

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. PMID:23202036

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

2012-01-01

152

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 µm were successfully filled and demolded.

2011-11-01

153

Flexural Properties of Injection-Molded Bamboo/pbs Composites  

Science.gov (United States)

In recent years, from an environmental perspective, there has been increasing interest in the change to a sustainable society. The use of natural-fiber-reinforced biodegradable composites has been proposed as one solution. Bamboo is an often used renewable bio-resource; it has an inherent advantage of rapid growth. Polybutylene succinate (PBS), used as matrix resin, has biodegradable characteristics. This paper describes flexural properties of bamboo/PBS composites prepared by injection molding. The following results were obtained. The flexural modulus was improved with increasing bamboo powder contents when the cylinder temperature of the injection molder was 140°C. However, the flexural strength showed the opposite tendency to be decreased with increasing bamboo powder contents. An SEM photomicrograph of the fracture surface for bamboo/PBS composites showed typical fracture behavior of pull-out fibers without fiber fracture. Furthermore, there was no adhesion of PBS resin on the bamboo fiber surface. Processing conditions affected mechanical properties of bamboo/PBS composites, imparting higher flexural strength and flexural modulus at high cylinder temperatures such as 180°C and 200°C.

Ohkita, Kazuya; Takagi, Hitoshi

154

Development of plastic pulley by injection molding; Shashutsu keisei ni yoru jushi pulley no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

We developed plastic pulley for automobile manufactured by injection molding which will reduce manufacturing cost. We have developed product design, injection molding technology especially to improve mechanical strength and phenolic molding compound with good wear resistance and high mechanical strength. We have established `Injection Compression molding` technology to improve mechanical strength of weld portion. We also developed phenolic molding compound which is composed of one step resin and long organic fiber to obtain good wear resistance and high mechanical strength. Manufacturing cost will be reduced by using injection molding combined with lower material cost of the newly developed compound. 12 figs., 2 tabs.

Yoshizumi, F.; Funatsu, A.; Yazawa, H. [Sumitomo Bakelite Co. Ltd., Tokyo (Japan)

1997-10-01

155

Measurement of solidification and melting behavior of resin in injection molding and detection of flaws molded parts by using ultrasonic waves  

International Nuclear Information System (INIS)

Injection molding of thermoplastics is widely used in many industries. However, it is not so easy to design the mold and to determine the optimal injection conditions. Therefore, a number of CAR mold design software packages for simulating the injection molding process have been developed. In order to confirm the results obtained from CAE, it is necessary to compare the numerical results with the experimental ones. In practice, the filling behavior has been observed with an optical visualization technique, but the solidification behavior of melted resin filled into the cavity has not yet been observed. It has been indirectly detected by measuring the pressure in the mold cavity. On the other hand, the melting behavior of solid resin in the barrel of an infection molding machine has influence on the quality of a molded part. Therefore, it is important to observe the melting behavior of solid resin in the barrel. In this study a method for measuring the solidification behavior in the cavity and the melting behavior in the barrel have been developed by using ultrasonic waves. Moreover, a method of detecting a flaw or a different material included in the molded part has been developed by using ultrasonic waves. Especially, a flaw close to the surface of the molded part can be detected by separating the flaw echo from the surface echo of the molded part. It was determined that the thickness of the solid layer of the melted resin filled into the cavity can be measured by using ultrasonic waves. The melting behavior of the resin on the barrel surface can be observed by measuring the amplitude of the reflected echo on the interface between the barrel and resin. Moreover, the flaw close to the surface of the molded part can be detected by using the ultrasonic waves.

156

Structural Changes of Injection Molded Starch During Heat Treatment in Water Atmosphere: Simultaneous Wide and Small-Angle X-ray Scattering Study  

OpenAIRE

Native starches with wide varying amylose content were processed by injection molding. The injection molded materials were conditioned in water for 20 days and sealed in glass capillaries. Simultaneous wide- and small angle X-ray scattering (WAXS and SAXS, respectively) were recorded during thermal heating using a synchrotron source. Crystallinity, SAXS invariant, Q, and long period, L, were measured as a function of heating temperature. The injection-molding process provokes a destruct...

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

2004-01-01

157

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 Taguchi’s orthogonal array. Analysis of variance (ANOVA in terms of signal-to-noise ratio (S/N-larger is better for green strength was also presented in this paper. Result shows that interaction between injection temperature and mold temperature (BxC give highest significant factor followed by interaction between injection pressure and injection temperature (AxB. Single factor that also contributes to significant optimization are mold temperature(C, injection time (D and injection pressure (A. Overall, this study shows that Taguchi method would be among the best method to solve the problem with minimum number of trials.

M.H.I Ibrahim

2010-06-01

158

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

International Nuclear Information System (INIS)

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

159

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

160

Metal Injection Molding (MIM of NdFeB Magnets  

Directory of Open Access Journals (Sweden)

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

Hartwig T.

2014-07-01

161

Metal Injection Molding (MIM) of NdFeB Magnets  

Science.gov (United States)

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

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

2014-07-01

162

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

163

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.

164

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

165

Anisotropic shrinkage in injection moldings of semicrystalline and amorphous polymers: Simulation and experiment  

Science.gov (United States)

A novel approach to predict anisotropic shrinkage of thermoplastic polymers in injection moldings was investigated in this study. The approach was based on the flow-induced crystallization, frozen-in molecular orientation, elastic recovery and PVT equation of state. The anisotropic thermal expansion coefficient and compressibility affected by the frozen-in orientation function and the elastic recovery that was not frozen during molding were introduced to obtain the anisotropic in-plane shrinkage. The frozen-in orientation function was obtained from the total birefringence, calculated from the amorphous contribution based on the frozen-in birefringence and the crystalline contribution based on the crystalline orientation function determined from the elastic recovery and intrinsic crystalline birefringence. To model the elastic recovery and frozen-in stresses related to birefringence during molding process, a non-linear viscoelastic constitutive equation was used with the temperature-, pressure- and crystallinity-dependent viscosity and relaxation time. Occurrence of the flow-induced crystallization was introduced through the elevated melting temperature affected by the entropy production of viscoelastic model. Kinetics of the crystallization was modeled using Nakamura and Hoffman-Lauritzen equations with the rate constant affected by the elevated melting temperature. Numerous injection molding runs on polystyrene, three different molecular weight polypropylenes and various polyesters of PET, PBT and PEN, were carried out by varying packing time, packing pressure, flow rate, melt temperature and mold temperature, and anisotropic shrinkage of moldings were measured. The experimental results were compared with the simulated data.

Kwon, Keehae

166

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; Hernández, P; Martinez, J; Pérez, J A; Mathia, T G

2014-01-01

167

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

OpenAIRE

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

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

2002-01-01

168

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

169

Rheological and Thermal Debinding Behaviors in Titanium Powder Injection Molding  

Science.gov (United States)

Powder injection molding (PIM) is suitable for the fabrication of complex shape titanium and its alloys and has a great potential in many applications. This article deals with the injection molding of hydride-dehydride (HDH) titanium powder, spheroidized HDH titanium powder, and gas-atomized (GA) titanium powder. Rheological and thermal debinding behaviors are compared between feedstocks made from the three powders. Torque and capillary rheometers are used to investigate rheological behavior as it relates to the power-law model of viscosity and moldability index. Thermogravimetric analysis (TGA) was employed to analyze debinding behavior given a master decomposition curve consisting of two sigmoids. Spheroidized HDH Ti powder behaves in a manner similar to GA Ti powder. The analysis of the results in this study indicates the possibility of using a combination of HDH and GA titanium powders for PIM.

Park, Seong-Jin; Wu, Yunxin; Heaney, Donald F.; Zou, Xin; Gai, Guosheng; German, Randall M.

2009-01-01

170

Advancements on the simulation of the micro injection moulding process  

DEFF Research Database (Denmark)

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

Marhöfer, David Maximilian; Tosello, Guido

2013-01-01

171

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

Science.gov (United States)

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

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

2013-11-01

172

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 ejection temperature, 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

173

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 170°C. The injection molding was carried out at low pressure. A combination of solvent and thermal debinding was used for binder removal, and then the samples were isothermally sintered at different sintering temperatures (900-1050°C in argon atmosphere. The results showed that the sintered samples experienced an isotropic shrinkage around 17% with relatively homogeneous dispersion of MWNTs in the copper matrix which is expected to enhance the physical and mechanical properties of the final product.

Norani M. Mohamed

2012-01-01

174

Computational simulation and experimental analysis of the mold-filling process in µPIM  

Science.gov (United States)

The micro powder injection molding technique has developed in recent years to be a unique method to fabricate miniature components in the large scale. In this paper numerical simulation of the mold filling of a micro-sized cylinder and gearwheel on a substrate was carried out with the ANSYS CFX software. The feedstock consisted of 56 vol% of carbonyl iron powder and a thermoplastic binder. The simulation results found that inhomogeneity greatly influences the shape precision of the molded micro-sized parts, and the gears located far from the gate exhibited better morphology than those near the gate. A difference in shape accuracy was found in different regions of a molded compact due to the variation of the state of the mold filling and the heat exchange between the feedstock and the die wall. The experimental data testified to the validity of the numerical simulation of the mold-filling process in micro powder injection molding.

Yin, Haiqing; Wang, Qing; Qu, Xuanhui; Jia, Chengchang; Johnson, John L.

2011-04-01

175

Expansion matched heat sinks made by ?-metal injection molding  

Science.gov (United States)

There is an ongoing and increasing interest in using expansion matched micro-channel heat sinks for high-power diode laser bars. In this new approach the heat sinks are produced by ?-metal injection molding (?-MIM). Unlike conventional heat sinks which are made of copper, these particular heat sinks are made of copper-tungsten because it combines two of low coefficient of thermal expansion (CTE) and reasonable thermal conductivity. Manufacturing heat sinks with the ?-MIM process allows for an economic mass production of complex micro near net shape parts. Especially when manufacturing over 10,000 parts with the ?-MIM process, manufacturing cost per part reduce considerably. The main goal is to use the opportunities ?-MIM offers. That means producing complex parts, which have a matched CTE in this case to gallium arsenide (GaAs). Therefore a material which combines high thermal conductivity behavior with a low coefficient of thermal expansion is needed. An additional advantage of the ?-MIM process is that the needed green bodies of the heat sink can be joint together in a co-sintering process. In this paper the current status of production of heat sinks with microstructured surfaces by ?-MIM for thermal management applications are presented. The range of operation and the limitations are outlined with special concern regarding the materials and the minimal structure size. The implication and advantages of using ultrafine powders are emphasized. Therefore sintering behavior, microstructure of sintered parts and characteristic properties as density, CTE, thermal conductivity and electro-optical characterization are shown identified.

Leers, Michael; Liermann, E.; Imgrund, P.; Kramer, L.; Volkert, J.

2010-02-01

176

New Design and Injection Molding Analysis of a Low Smoke Zero Halogen Cable Trunk  

OpenAIRE

The traditional production process of a cable trunk is plastic extrusion with PVC or other halogen containing materials. However, they have many disadvantages such as easy burning, producing toxic gases and smokes. A low smoke zero halogen (LSZH) cable trunk was designed and developed in the present study and the injection molding process was adopted to produce the LSZH cable trunk. Numerical simulations were applied to investigate the effects of the important process parameters on the war...

Xiaoxun Zhang; Fang Ma; Xia Li

2012-01-01

177

Residual stresses and birefringence in gas-assisted injection molding of amorphous polymers: Simulation and experiment  

Science.gov (United States)

This study presents measurements and simulations of the distribution of the birefringence components, Deltan and n rr-nthetatheta, and the average birefringence, , and polymer/gas interface in polystyrene (PS) and polycarbonate (PC) spiral-shaped tubular moldings obtained by Gas-Assisted Injection Molding (GAIM) under various processing conditions. Furthermore, free quenching experiments in cylindrical samples were carried out at different initial temperatures, and various components of birefringence and stresses were measured and simulated. The flow- and thermally-induced stresses were simulated using linear and nonlinear viscoelastic theories, respectively. The flow- and thermally-induced birefringence components were calculated using the stress-optical rule and photoviscoelastic model, respectively. The governing equations of the GAIM process were derived using a nonlinear viscoelastic model and solved using a hybrid finite element/finite difference/control volume method. The governing equations to calculate the thermally-induced stresses were discretized using finite differences. The numerical results predicted qualitatively the effect of the processing variables on the polymer/gas interface distribution of the GAIM moldings. It was found that the processing variables that strongly affected the interface distribution were the injection speed, gas-delay time, and the shot size. The processing variables that exerted less influence on the polymer/gas distribution were the gas pressure and the melt and mold temperatures. The processing variables that strongly affected the birefringence Delta n were the melt temperature, injection speed, and gas-delay time. The mold temperature, gas pressure and shot size exerted less influence on Delta n. For PS GAIM moldings the measured birefringence near to the outer wall did not relax when a section was annealed at a temperature close to the glass transition temperature while the birefringence near to the inner wall did relax significantly. This observation was consistent with the idea that the birefringence at the outer wall was mainly induced by shear and normal stresses, while that at the inner wall was induced by thermal stresses. For PC GAIM moldings the measured Deltan and n rr-nthetatheta relaxed significantly near the inner and outer walls, suggesting that the thermally-induced stresses exerted a strong influence on the birefringence throughout the wall thickness. The simulated birefringence qualitatively described the measurements. Summation of simulated thermally- and flow-induced birefringence provided a better description of measured birefringence in PS GAIM moldings. However, for PC GAIM moldings, simulations showed large discrepancies. This was attributed to the strong influence of thermally-induced birefringence throughout the wall thickness of the molding. Melt temperature, gas-delay time, and injection speed strongly affected the average birefringence in PS GAIM moldings while the shot size and gas pressure exerted less influence. For PS GAIM moldings the contribution of the thermally-induced average birefringence was minimal while for PC GAIM moldings it was significant.

Carrillo-Ojeda, Antonio

178

Properties of 17-4 PH stainless steels produced by metal injection molding process; Kinzoku funmatsu shashutsu seikei process ni yoru 17-4 PH stainless ko no shotokusei  

Energy Technology Data Exchange (ETDEWEB)

Metal injection molding (MIM) process is hoped to be an advanced powder processing technique for the attributes of forming the high density, complex shaped and high performance components. This process also alleviates the need for secondary working operations because of the net shape forming, which is a suitable production route for the hard materials. In this study, the effects of MIM processing variations on the mechanical properties and microstructures of precipitation-hardenable 17-4 PH stainless steels were investigated. Carbon content, density, structure, and properties of the MIM steels were very dependent on the debinding, wintering, an heat treatment conditions. Especially, the amount of retained austerity in the structure increased with an increase of the residual carbon content, resulting in poor mechanical properties. Accordingly, the carbon control was a very important operation for this steel, which was successfully performed by adjusting the weight loss of debound compacts. Finally, high performance properties comparable to those of wrought steels were obtained by optimizing the heat treatments. 6 refs., 10 figs., 1 tab.

Baba, T. [Kumamoto University, Kumamoto (Japan); Miura, H.; Honda, T. [Kumamoto University, Kumamoto (Japan). Faculty of Engineering; Tokuyama, Y. [Mitsubishi Steel MGF, Co. Ltd., Tokyo (Japan)

1995-10-15

179

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

OpenAIRE

The utilization of stereolithography molds in the manufacture pre-series for injection molded plastic parts aims to reduce costs throughout the product life-time, but mainly during design and manufacturing phases. The use of this Rapid Tooling technique in powder metal injection molding is evaluated in this work. One of the greatest differences between traditional and stereolithography tools is related to the heat conductivity of the materials employed. For example, steel molds have a heat co...

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

2004-01-01

180

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

Scientific Electronic Library Online (English)

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

Carlos de Oliveira, Affonso; Renato José, Sassi.

181

Dimensional variation in production of high-aspect-ratio micro-pillars array by micro powder injection molding  

Science.gov (United States)

Micro powder injection molding (?PIM) is one of the potential processes for the mass production of metallic microstructures and micro components. Here, ?PIM is the miniaturization of conventional PIM, which involves four processing steps: mixing, injection molding, debinding and sintering. This paper looks into the feasibility and effectiveness of ?PIM as a key mass production process for the fabrication of metallic micro components. For it to be an effective re-production process, it is imperative to examine how well parts can be duplicated/fabricated from a master mold. In this work, the dimensional variation of high-aspect-ratio micro-pillars arrays, in particular the dimensional shrinkage, global warpage, and surface roughness at each stage of the ?PIM process for a range of molding pressures, are quantified and compared in detail. The sensitivity of the dimensional variation of the microstructures to the packing pressure is reported. The mechanism behind the dimensional variation is analyzed.

Li, S. G.; Fu, G.; Reading, I.; Tor, S. B.; Loh, N. H.; Chaturvedi, P.; Yoon, S. F.; Youcef-Toumi, K.

2007-11-01

182

Environmental impact estimation of mold making process  

Science.gov (United States)

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

Kong, Daeyoung

183

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

Energy Technology Data Exchange (ETDEWEB)

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

Zlatkov, B.S. [FOTEC Forschungs- und Technologietransfer GmbH, Viktor Kaplan-Strasse 2, 2700 Wiener Neustadt (Austria); Nikolic, M.V. [Institute for Multidisciplinary Research, Kneza Viseslava 1, 11000 Beograd (Serbia)], E-mail: mariavesna@cms.bg.ac.yu; Aleksic, O. [Institute for Multidisciplinary Research, Kneza Viseslava 1, 11000 Beograd (Serbia); Danninger, H.; Halwax, E. [Institute of Chemical Technologies and Analytics, Getreidemarkt 9/164, 1060 Wien (Austria)

2009-02-15

184

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

Science.gov (United States)

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

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

2009-02-01

185

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

International Nuclear Information System (INIS)

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

186

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, Søren; Christensen, Mette Thylstrup; Garnaes, Joergen; Wilson, Sandra; Kutchinsky, Jonatan; Taboryski, Rafael

2013-12-21

187

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 µm × height 191 µm 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 µm × height 174 µm with an aspect ratio of 4.35 and 20 µm × height 160 µm with an aspect ratio of 8 were molded successfully.

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

2007-09-01

188

Metal Injection Molding (MIM) of NdFeB Magnets  

OpenAIRE

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

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

2014-01-01

189

A 3D study on the effect of gate location on the cooling of polymer by injection molding  

Energy Technology Data Exchange (ETDEWEB)

Injection molding is one of the most widely used plastic part processing. The quality of the injection molded part is a function of plastic material, part geometry, mold structure and process conditions. Gate location is among the most critical factors in achieving dimensionally accurate parts and high productivity of the molding process. To investigate the effect of the gate location on the cooling of polymer by injection molding, a full three dimensional time-dependent analysis is carried out for a mold with cuboids-shape cavity having two different thicknesses. The cooling of the polymer material is carried out by cooling water flowing inside six horizontal circular channels. Three gate locations are assumed, normal to the cavity surface, normal to the small thickness of the cavity, and normal to the large thickness of the cavity. A numerical model by finite volume is used for the solution of the physical model. A validation of the numerical model is presented. The results show that the gate location normal to the small thickness of the cavity achieves the minimum time required to completely solidify the product and minimum solidification of the product during the filling stage. They also indicate that the temperature distribution through the output product is greatly affected by the position of the injection gate location.

Hassan, Hamdy, E-mail: hassan@enscpb.f [TREFLE Laboratory, Bordeaux 1, UMR 8508, Site ENSCPB, 16 av Pey Berland, 33607 Pessac Cedex (France); Regnier, Nicolas; Defaye, Guy [TREFLE Laboratory, Bordeaux 1, UMR 8508, Site ENSCPB, 16 av Pey Berland, 33607 Pessac Cedex (France)

2009-12-15

190

A 3D study on the effect of gate location on the cooling of polymer by injection molding  

International Nuclear Information System (INIS)

Injection molding is one of the most widely used plastic part processing. The quality of the injection molded part is a function of plastic material, part geometry, mold structure and process conditions. Gate location is among the most critical factors in achieving dimensionally accurate parts and high productivity of the molding process. To investigate the effect of the gate location on the cooling of polymer by injection molding, a full three dimensional time-dependent analysis is carried out for a mold with cuboids-shape cavity having two different thicknesses. The cooling of the polymer material is carried out by cooling water flowing inside six horizontal circular channels. Three gate locations are assumed, normal to the cavity surface, normal to the small thickness of the cavity, and normal to the large thickness of the cavity. A numerical model by finite volume is used for the solution of the physical model. A validation of the numerical model is presented. The results show that the gate location normal to the small thickness of the cavity achieves the minimum time required to completely solidify the product and minimum solidification of the product during the filling stage. They also indicate that the temperature distribution through the output product is greatly affected by the position of the injection gate location.

191

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

International Nuclear Information System (INIS)

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

192

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

Science.gov (United States)

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

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

2001-05-01

193

On the Injection Molding of Nanostructured Polymer Surfaces  

DEFF Research Database (Denmark)

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

Pranov, Henrik; Rasmussen, Henrik K.

2006-01-01

194

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

195

Manufacturing of ceramic-metal composites by combining tape casting and injection molding  

OpenAIRE

In industry, material composites are of great interest if new applications can be developed by combining their physical properties. In two-component powder injection molding materials are required that can be co-fired, and that are characterized by an adjusted, stress-defined expansion behavior in the manufacturing process and application area. Additionally, powder packing concepts for the different materials of the feedstock are a crucial factor, as the green densities correlate with the exp...

Baumann, A.; Lenk, R.; Moritz, T.

2007-01-01

196

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

197

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

Science.gov (United States)

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

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

2014-05-01

198

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

199

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-Hernández M.

2012-10-01

200

Particle morphology influence on mechanical and biocompatibility properties of injection molded Ti alloy powder.  

Science.gov (United States)

Titanium and Titanium alloys exhibits properties that are excellent for various bio-applications. Metal injection molding is a processing route that offers reduction in costs, with the added advantage of near net-shape components. Different physical properties of Titanium alloy powders, shaped and processed via injection molding can achieve high complexity of part geometry with mechanical and bioactivity properties, similar or superior to wrought material. This study describes that the effect of particle morphology on the microstructural, mechanical and biocompatibility properties of injection molded Ti-6Al-4V (Ti64) alloy powder for biomaterials applications. Ti64 powders irregular and spherical in shape were injection molded with wax based binder. Binder debinding was performed in solvent and thermal method. After debinding the samples were sintered under high vacuum. Metallographic studies were determined to densification and the corresponding microstructural changes. Sintered samples were immersed in a simulated body fluid (SBF) with elemental concentrations that were comparable to those of human blood plasma for a total period of 15 days. Both materials were implanted in fibroblast culture for biocompatibility evaluations were carried out. The results show that spherical and irregular powder could be sintered to a maximum theoretical density. Maximum tensile strength was obtained for spherical shape powder sintered. The tensile strength of the irregular shape powder sintered at the same temperature was lower due to higher porosity. Finally, mechanical tests show that the irregular shape powder has lower mechanical properties than spherical shape powder. The sintered irregular Ti64 powder exhibited better biocompatibility than sintered spherical Ti64 powder. Results of study showed that sintered spherical and irregular Ti64 powders exhibited high mechanical properties and good biocompatibility properties. PMID:25201399

Gülsoy, H Özkan; Gülsoy, Nagihan; Cal???c?, Rahmi

2014-01-01

201

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

202

Development of Defects Free Stainless Steel Parts Using Powder Injection Molding  

OpenAIRE

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 ...

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

2013-01-01

203

Mold design  

International Nuclear Information System (INIS)

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

204

Computer-aided design and fabrication of molds and computer control of injection molding  

Science.gov (United States)

Modeling flow in cavity, runner system, and junctures is considered, with emphasis on three areas: (1) filling cavities of variable gap thickness; (2) development of boundary integral method for slow viscous flow in juncture regions; and (3) a procedure for balancing systems. Viscoelastic modeling is addressed as well as two principal approaches to the construction of constitutive equations for polymer melts or concentrated polymer solutions: (1) molecular-network theories, and (2) continuum mechanical theories. Attention is focused on rheology and injection molding of glass filled thermoplastics. Progress is reported on developing a parts operation system which provides a flexible environment in which the user can create more complex geometries based on geometric data files of TIPS-1, a solid geometric modeler.

Wang, K. K.; Shen, S. F.; Cohen, C.; Hieber, C. A.; Isayev, A. I.

1982-11-01

205

Molds  

Science.gov (United States)

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

206

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

207

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

208

Conformal cooling and rapid thermal cycling in injection molding with 3D printed tools  

Science.gov (United States)

Solid Freeform Fabrication processes such as 3D Printing have demonstrated the potential to produce tools with complex internal geometry. This work explores the application of this capability to improved thermal management for injection molding tooling through: (i)cooling lines which are conformal to the mold surface which provide improved uniformity and stability of mold temperature and (ii)tools with low thermal inertia which, in combination with conformal fluid channels allow for rapid heating and cooling of tooling, thereby facilitating isothermal filling of the mold cavity. This work presents a systematic, modular, approach to the design of conformal cooling channels. Recognizing that the cooling is local to the surface of the tool, the tool is divided up into geometric regions and a channel system is designed for each region. Each channel system is itself modeled as composed of cooling elements, typically the region spanned by two channels. Six criteria are applied including; a transient heat transfer condition which dictates a maximum distance from mold surface to cooling channel, considerations of pressure and temperature drop along the flow channel and considerations of strength of the mold. These criteria are treated as constraints and successful designs are sought which define windows bounded by these constraints. The methodology is demonstrated in application to a complex core and cavity for injection molding. In the area of rapid thermal cycling, this work utilizes the design methods for conformal channels for the heating phases and adds analysis of the packing and cooling phases. A design is created which provides thermal isolation and accommodation of cyclic thermal stresses though an array of bendable support columns which support the molding portion of the tool where the heating/cooling channels are contained. Designed elasticity of the tool is used to aid in packing of the polymer during the cooling phase. Methodology for the design of this structure is presented. A set of tools has been fabricated and subjected to thermal and mechanical tests. (Copies available exclusively from MIT Libraries, Rm. 14- 0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

Xu, Xiaorong

209

Highly conductive thermoplastic composite blends suitable for injection molding of bipolar plates  

International Nuclear Information System (INIS)

This study aimed at developing highly conductive, lightweight, and low-cost bipolar plates for use in proton exchange membranes (PEM) fuel cells. Injection and compression molding of highly filled polypropylene, PP, and polyphenylene sulfide, PPS, based blends were used as a mean for mass production of bipolar plates. Loadings up to 60-wt% in the form of graphite, conductive carbon black and carbon fibers were investigated. The developed formulations have a combination of properties and processability suitable for bipolar plate manufacturing, such as good chemical resistance, sufficient fluidity, and good electrical and thermal conductivity. Electrical resistivities around 0.15 and 0.09 Ohm-cm were respectively achieved for the PP and PPS-based blends, respectively. Two bipolar plate designs were successfully fabricated by molding the gas flow channels over aluminum plates to form a metallic/polymer composite plate, or simply by direct injection molding of the conductive polymer composite. For the first design, overall plate resistivities of 0.2 and 0.1 Ohm-cm were respectively attained using PP and PPS based blends as conductive skin. A lower volume resistivity of around 0.06 Ohm-cm was attained for the second injected plate design with PPS based blend. (author)

210

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

211

Investigation of sample preparation on the moldability of ceramic injection molding feedstocks  

Science.gov (United States)

Ceramic injection molding is a desirable option for those who are looking to make ceramic parts with complex geometries. Formulating the feedstock needed to produce ideal parts is a difficult process. In this research a series of feedstock blends will be evaluated for moldability. This was done by investigating their viscosity, and how certain components affect the overall ability to flow. These feedstocks varied waxes, surfactants, and solids loading. A capillary rheometer was used to characterize some of the materials, which led to one batch being selected for molding trials. The parts were sintered and further refinements were made to the feedstock. Solids loading was increased from 77.5% to 82%, which required different ratios of organics to flow. Finally, the ceramic powders were treated to lower their specific surface area before being compounded, which resulted in materials that would process easily through an extruder and exhibit properties suitable for CIM.

Ide, Jared

212

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

213

Warpage Generation Mechanism by Cooling Speed Distribution in Actual Injection Molding  

Science.gov (United States)

In some cases, warpage failure occurs in the injection molding plate. This warpage can be predicted by using injection molding CAE. However, the prediction accuracy is not enough in the warpage analysis of injection molding CAE. The warpage generation mechanism changes according to the material and shape. The mechanism has not been clarified in each condition. For example, there is difference in the cooling speed of the real injection plate in each position. In this report, we considered the influence of the difference of mold temperature on warpage, assuming the mold temperature to be an asymmetric condition. And the following conclusions were arrived at. Moreover, upon examining the influence of mold temperature difference on warpage of PP plate, the following conclusions were obtained. 1) The amount of warpage grows in an asymmetrical mold temperature condition. The amount of warpage increases in the case of high mold temperature even if the difference of temperature between fixed side and moved side is constant. 2) In the case of asymmetrical mold temperature, the distribution of crystallinity becomes asymmetrical in the thickness direction. However, the thermal expansion coefficient is isotropy and constant. 3) The key factor of warpage in asymmetrical mold temperature conditions in PP is induced by thermal effect. 4) The resin flow of asymmetrical mold temperature conditions in PP becomes a symmetrical flow. This is thought to be influenced by heat of shearing and latent heat of crystallization. 5) Even under the same mold temperature asymmetric condition, differences in material cause the influence of mold temperature on flow to differ.

Satoh, Kazuhito; Matsubara, Eiji; Yamabe, Masashi

214

Optimization of Micro Metal Injection Molding By Using Grey Relational Grade  

International Nuclear Information System (INIS)

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

215

Development of Sensorless Force Control System Based on Nonlinear Friction Phenomenon for Electric Injection Molding Machine  

Science.gov (United States)

Currently, most of the plastic products are manufactured by using injection molding machines. The quality of the products depends largely on the injection force. In a typical force control system of an injection molding machine, the information about the force in the machine environment is obtained by a force sensor. However, force sensors have a few disadvantages such as signal noise, high sensor cost and narrow bandwidth. We have proposed the use of a reaction force observer based on the two-inertia resonant model. However, this method has some estimated error caused by a static friction in the holding process and a Coulomb friction in the screw back-pressure process. The estimation accuracy of the reaction force observer depends on parameter variations and the non-linear friction phenomenon. This paper proposes a new injection-force-estimation method based on the proposed high-order reaction force observer (HORFO), which is not influenced significantly by the nonlinear friction phenomenon. The effectiveness of the proposed method is confirmed by experimental results.

Furusawa, Ryo; Asai, Tetsuya; Ohishi, Kiyoshi; Majima, Katsuyuki; Kageyama, Kouichi; Takatsu, Masaru; Urushihara, Shirou

216

New Virtual Environment for Active Learning on Parameter Adjustment of Plastic Injection Molding  

OpenAIRE

This paper describes some aspects of new software development and its academic application. This program is an alternative to enhance and to improve the available resources for students to acquire practical knowledge in plastic injection molding parameterization. A virtual injection molding environment has been developed, which allows preliminary machine capacity determination, number of cavities analysis, injection cycle parameter definition, and defects analysis and representation. The envi...

Marquez Sevillano, Juan Juanes; Rodri?guez Villagra?, Mari?a; Martinez Muneta, M. Luisa; Pe?rez Garci?a, Jesus Maria

2009-01-01

217

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

218

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

International Nuclear Information System (INIS)

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

219

The manufactoring of a two–layered injection mold by welding  

OpenAIRE

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 ...

Kos?nik, A.; Tus?ek, J.; Kosec, L.; Muhic?, T.

2011-01-01

220

Simulation and experiment research on the proportional pressure control of water-assisted injection molding  

Science.gov (United States)

Water-assisted injection molding (WAIM), a newly developed fluid-assisted injection molding technology has drawn more and more attentions for the energy saving, short cooling circle time and high quality of products. Existing research for the process of WAIM has shown that the pressure control of the injecting water is mostly important for the WAIM. However, the proportional pressure control for the WAIM system is quite complex due to the existence of nonlinearities in the water hydraulic system. In order to achieve better pressure control performance of the injecting water to meet the requirements of the WAIM, the proportional pressure control of the WAIM system is investigated both numerically and experimentally. A newly designed water hydraulic system for WAIM is first modeled in AMEsim environment, the load characteristics and the nonlinearities of water hydraulic system are both considered, then the main factors affecting the injecting pressure and load flow rate are extensively studied. Meanwhile, an open-loop model-based compensation control strategy is employed to regulate the water injection pressure and a feedback proportional integrator controller is further adopted to achieve better control performance. In order to verify the AMEsim simulation results WAIM experiment for particular Acrylonitrile Butadiene Styrene (ABS) parts is implemented and the measured experimental data including injecting pressure and flow rate results are compared with the simulation. The good coincidence between experiment and simulation shows that the AMEsim model is accurate, and the tracking performance of the load pressure indicates that the proposed control strategy is effective for the proportional pressure control of the nonlinear WAIM system. The proposed proportional pressure control strategy and the conclusions drawn from simulation and experiment contribute to the application of water hydraulic proportional control and WAIM technology.

Zhou, Hua; Chen, Yinglong; Zhang, Zengmeng; Yang, Huayong

2012-05-01

221

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

International Nuclear Information System (INIS)

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

222

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

223

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

International Nuclear Information System (INIS)

Highlights: ? Sintering, microstructural and mechanical properties of injection molded nickel based 625 superalloy were studied. ? The maximum sintered density achieved this study was 98.3% at 1300 °C for 3 h. ? 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 °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.characteristics of cast alloy 625.

224

Birefringence, anisotropic shrinkage and luminance in injection molded light-guide plate: Modeling and experiment  

Science.gov (United States)

Liquid crystal displays (LCDs) with edge-lit backlight system have been widely used in industry due to several advantages over traditional cathode-ray tubes (CRTs). The main component of the backlight system is the light-guide plate (LGP) which is designed to provide the highest possible degree of light concentration and luminance efficiency. However, the relationship between processing conditions in manufacturing and their optical performance have not been established. In addressing this issue, LGP moldings were made of optical grade polycarbonates (PCs) of low and high viscosity and a polystyrene (PS). The theoretical and experimental studies on the effect of the processing conditions on the anisotropic shrinkage, residual stresses and birefringence, and resulting luminance in the injection molded V-groove LGPs were carried out. The stress-optical coefficient and relaxation modulus functions of polymers were obtained by specially designed rheo-optical instrument. These functions were incorporated to the linear viscoelastic and photoviscoelastic constitutive equations to predict the thermal birefringence in constrained, freely quenched plates and LGP moldings. The flow-induced birefringence and anisotropic shrinkage of LGPs were simulated by using a combination of a CV/FEM/FDM technique, a nonlinear viscoelastic constitutive equation, and orientation functions. The residual normal and transverse birefringence in LGPs along with shrinkages were measured. The predicted total birefringence was obtained by a summation of the predicted flow- and thermally-induced birefringence. Numerical results were compared with measurements at various processing conditions indicating a good agreement in the anisotropic shrinkage and a fair agreement in the residual birefringence. The luminance as a function of a viewing angle on the injection molded LGPs at various molding conditions was measured by means of the device that was built for this purpose. Strong effects from the processing conditions on optical performance were found. The results indicated that the LGPs made of low viscosity PC exhibited the best light concentration and the highest luminance while LGPs made of PS showed the lowest optical performance. Also, it was found that the luminance of LGPs showed a strong correlation with the depth of melt filling of the V-grooves and some correlation with the frozen-in birefringence.

Lin, Tsui-Hsun

225

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

OpenAIRE

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 chara...

Jamaludin, K. R.; Ruzi, M.; Ariffin, A. K.; Muhamad, N.; Mohamad Nor, N. H.; Sufizar, A.

2011-01-01

226

Design Optimization of Stationary Platen of Plastic Injection Molding Machine Using FEA  

OpenAIRE

Plastic are certainly most versatile of all known materials today and have therefore, established themselves in enviable position from where are not even possible to replaced. Injection molding machine is one of the most widely used method of conversion of plastic into various end products application to wide range of plastic materials from plastic commodity to specialty engineering plastic.In injection molding machine stationary platen play a very important role. During the p...

Dheeraj Mandliya*1; Yogesh Agrawal2; Seshagiri Rao, G. V. R.

2014-01-01

227

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

DEFF Research Database (Denmark)

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

ArlØ, Uffe Rolf; Kjær, Erik Michael

2001-01-01

228

Numerical modeling of magnetic induction and heating in injection molding tools  

DEFF Research Database (Denmark)

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

Guerrier, Patrick; Hattel, Jesper Henri

2013-01-01

229

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

Scientific Electronic Library Online (English)

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

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

230

Design Optimization of Stationary Platen of Plastic Injection Molding Machine Using FEA  

Directory of Open Access Journals (Sweden)

Full Text Available Plastic are certainly most versatile of all known materials today and have therefore, established themselves in enviable position from where are not even possible to replaced. Injection molding machine is one of the most widely used method of conversion of plastic into various end products application to wide range of plastic materials from plastic commodity to specialty engineering plastic.In injection molding machine stationary platen play a very important role. During the process generally compressive stress generates at particular regions. As load varies with fast rate there is chance to failure of tie bar rod. Due to heavy mould shape, size of platen also change, that’s increase its weight as well as stress level at certain region and this is not good in practice . This leads to failure of platen or failure of tie rod due to stretching by nut and platen. This create loss of money (Production stop, man (injured due to accident, and material (increase inventory cost. The aim of this project is study about those areas where stress can affect the failure of tie bar due to heavy weight of stationary platen the deflection or misalignment with movable platen. Finally redistribution of stress sothat uniforme stress achive (optimization of platen. This project is including Finite Element Analysis and Design Optimization of a Typical Structural Component of a Plastic Injection Molding Machine. The aim of project is to optimize a typical structural component (stationary platen by using finite element analysis after checking induced stresses with allowable design stress. Hence design modification of platen is carried out to achieve good strength and cost effectiveness.

Dheeraj Mandliya*1

2014-05-01

231

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

232

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)

233

Simulation of the injection moulding process  

Science.gov (United States)

Simulation of the injection molding process is a helpful way for the engineers who work with plastics processing. By simulation, they will get some important parameters which sometimes are highly necessary for the mold design and processing. Thus, the engineers will save much time to do experiments for the parameters. Two simulation programs are used in this report, namely CADMOULD and CADMOULD MEFISTO which are designed by Institut fur Kunststoffverarbeitung (IKV) in Aachen, W. Germany. CADMOULD works with 2-D geometry and is specialized for rheological, thermal and mechanical calculation. It is installed on a personal computer, while CADMOULD MEFISTO works in 3-D and is installed on a VAX 8530 computer at SINTEF. A PC version of this program is also available. This report deals with CADMOULD and CADMOULD MEFISTO. The construction of flow lines, balancing of sprue system, the optimizing of injection time, and gate(s) optimizing are mainly included.

Hu, J.; Christensen, T.

1993-12-01

234

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

Directory of Open Access Journals (Sweden)

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

P . A. Ourique

2013-03-01

235

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

Scientific Electronic Library Online (English)

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

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

2013-03-01

236

Processes at the inetrface molten metal-sand mold  

OpenAIRE

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

Janjus?evic?, Z.; Gulis?ija, Z.; Mihailovic?, M.; Pataric?, A.

2014-01-01

237

Improved molding process ensures plastic parts of higher tensile strength  

Science.gov (United States)

Single molding process ensures that plastic parts /of a given mechanical design/ produced from a conventional thermosetting molding compound will have a maximum tensile strength. The process can also be used for other thermosetting compounds to produce parts with improved physical properties.

Heier, W. C.

1968-01-01

238

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-01-01

239

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 Peased 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.

240

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

241

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

DEFF Research Database (Denmark)

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

Tanzi, Simone; Larsen, Simon Tylsgaard

242

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

243

Mold  

Science.gov (United States)

... assistance from the U.S. Department of Housing and Urban Development, to help quantify mold contamination. ERMI allows researchers ... guidelines for indoor air quality: dampness and mould. Germany: Druckpartner Moser. 4 NTP (National Toxicology Program). 2006. ...

244

Mold temperature measurement for glass-pressing processes  

International Nuclear Information System (INIS)

The largest use of radiation thermometers within Corning Glass Works is for mold temperature measurement for the glass-pressing process. Pressing television panels at today's high quality would be very difficult without a mold temperature measurement system and the computer manipulation of the quality control data to supervise the mold temperature control loop. The most critical part of a television panel is the inside surface curvature. The ideal surface is usually defined as a spherical surface. The tolerance for a normal TV panel is +-0.30 mm (+-0.012 in.). High resolution display panels are more critical, having a dimensional tolerance only one half as large as TV panels. Panel curvature is a direct (but negative) function of mold temperature. Every 10C increase in mold temperature results in the panel center being 0.025 mm (0.001 in.) shorter (flatter). Random dimensional variations within a panel take up most of the dimensional tolerance. The result is that each mold is controlled to its own individual temperature set point, +-10C. Hot panel and cold panel curvature measurements are correlated by a process computer and used to update the mold temperature set points. The same computer adjusts the mold cooling air to maintain the required mold temperatures. From the temperature measurement standpoint, the significant problem is the changing emissivity of the mold surface when the mold is new or reconditioned. The selection of a radiation theritioned. The selection of a radiation thermometer with a short wavelength was an obvious choice to minimize the effect of emissivity variations

245

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.

Bloß, P.; Jüttner, G.; Jacob, S.; Löser, C.; Michaelis, J.; Krajewsky, P.

2014-05-01

246

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2014-05-15

247

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

248

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

Scientific Electronic Library Online (English)

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

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

2012-12-01

249

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

250

A study on gas penetration and fingering behavior in injection molding of polymer and powder metal feedstock  

Science.gov (United States)

The effect of processing variables on the level of gas penetration in parts fabricated by gas-assisted injection molding from two different materials was compared. The materials used were polypropylene and stainless steel powder metal/thermoplastic feedstock. Software simulation and physical experiments were conducted. Taguchi analysis was used to reduce the number of experiment trials and to find the optimum processing conditions. Four different variables were changed using nine different combinations. The processing variables are the pressure, the delay time before gas is injected, the temperature of the material injected, and the amount of the material injected. The results showed that the most critical variable in the experiment is shot size followed by gas pressure, delay time and material.

Orozco, Edna I.

251

Free-flow electrophoresis with electrode-less injection molded chips  

Science.gov (United States)

In this work we present the first approach towards low-cost free-flow electrophoresis (FFE) devices utilizing injection molding as a microfabrication process which has the potential to manufacture FFE chips at a cost which make their use commercially viable. This is achieved by realizing a new straightforward micro free-flow electrophoresis (?FFE) design ensuring both, bubble free electrophoretic separation and effective electrical connection by implementing miniaturized partitioning bars. This creates a defined open gap of 20 ?m in height and 500 ?m in width between separation zone and electrode channels. The thermoplastic ?FFE chips are ready to use, there is no need for a subsequent labor-intensive implementation of membranes or salt bridges to separate the electrode channels from the separation zone.

Köhler, Stefan; Becker, Holger; Beushausen, Volker; Hüttner, Wilhelm; Wackerbarth, Hainer; Beckert, Erik; Howitz, Steffen; Belder, Detlev

2011-02-01

252

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

DEFF Research Database (Denmark)

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

Matteucci, Marco; Christiansen, Thomas Lehrmann

2013-01-01

253

Effect of shear heating during injection molding on the morphology of PC/LCP blends  

International Nuclear Information System (INIS)

Fiber relaxation of liquid crystalline polymer (LCP) in the mold during injection molding was investigated. A blend of LCP and polycarbonate was used. The LCP used, namely LC5000, is a thermotropic LCP consisting of 80% and 20% of hydroxybenzoic acid and ethylene terephthalate, respectively. The filling of the mold and the temperature profile of the melt in the mold, after the mold has been completely filled, were computed using the finite element/finite difference method (FE/FDM). The morphology of the fibers was greatly influenced by the temperature of the different layers in the sample. This was confirmed by scanning electron microscopy (SEM) examination of the injection-molded specimen. When shear heating caused the temperature of the melt to increase above 280 deg. C, relaxation of the fibers was rapid. This resulted in a final morphology where the LCP existed in short fibers or ellipsoids. It was concluded that the high shear rate, which is needed for fiber deformation, must be accompanied by fast cooling to minimize the effects of shear heating, so that the fibers formed could be retained

254

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

International Nuclear Information System (INIS)

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 ? + ?. 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

255

Magnetic properties of Fe–50%Ni alloy fabricated by metal injection molding  

International Nuclear Information System (INIS)

Graphical abstract: The figure shows the effect of sintering atmosphere on microstructures of the samples ((a) nitrogen; (b) argon; (c) vacuum; and (d) hydrogen). Since pores can pin down and drag grain boundary movement, the porosities obtained from the four different processes are different. It can be seen that the grain sizes of the sample sintered in the atmosphere of nitrogen, argon and vacuum are smaller than the grain size of sample sintered in hydrogen. It indicates that the impurity such as C, N, O will restrict the grain growth and lead to the sharp decrement of magnetic performance. - Highlights: • High-performance Fe–50%Ni alloy was produced by metal injection molding. • The magnetic properties were closely related to impurities and grain size. • The sintering parameters of Fe–50%Ni alloy were optimized. - Abstract: Fe–50%Ni soft magnetic alloys are attractive in their applications with both low coercivity and high permeability. Their magnetic properties are closely related to sintering conditions. In this paper, Fe–50%Ni soft magnetic alloys were successfully produced by metal injection molding using carbonyl iron and carbonyl nickel as raw materials. The effects of sintering temperature, sintering atmosphere and time on the magnetic properties of the alloy were investigated. Special attention was paid to the influence that sintering conditions have on chemistry and the resulting effects on magnetic properties. The results indicated that the magnetic permeability was greatly dependent on the content of interstitial atom such as C, O, and N and the density was a major factor affecting the saturation induction. Furthermore, the effects of processing condition on the microstructures of Fe–50%Ni alloy were shown. The optimum magnetic properties for Fe–50%Ni alloy were obtained by maximizing density and sintering temperatures, and minimizing the contamination levels of C, O and N

256

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

257

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

258

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

OpenAIRE

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

Gazzaniga, Andrea; Cerea, Matteo; Cozzi, Alberto; Foppoli, Anastasia; Maroni, Alessandra; Zema, Lucia

2011-01-01

259

Study of mold elastic rigidity during UV imprinting process  

Science.gov (United States)

The duration and magnitude of imprinting pressure are very influential in the imprinting process, especially in window-open imprinting process. Resin flows spread over the imprinting area according to both the squeeze motion of the mold and the pressure gradient of the mold cavity-protrusion structure, which causes relatively large contact pressure concentrated in certain locations on the imprinting area. The concentrated contact pressure distorts the mold shape, which then results in pattern distortion. When the pattern density of the mold is unevenly distributed, especially across a large imprinting area, pattern distortion is easily influenced by the rigidity of the mold. To avoid pattern distortions, the imprinting period, and the magnitude and rate of the imprinting pressure must be optimized. In this study, variations in resin layer thickness and elastic deformation of mold materials are analyzed using elastohydrodynamic lubrication (EHL) theory. The film thicknesses of the resin layer are computed down to ˜nm and compared with the consideration of the elastic rigidity of the mold materials and without. [Figure not available: see fulltext.

Jang, Siyoul

2014-11-01

260

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

261

Study on manufacture of 2:17 Sm-Co magnets by powder injection molding  

International Nuclear Information System (INIS)

Manufacture of 2:17 Sm-Co magnets by powder injection molding was investigated. The binder of thermoplastic polymer was selected as the wax-based system including paraffin wax, stearic acid and high density polyethylene. Before mixing with paraffin wax and high density polyethylene, the powder of 5-8 ?m was coated by stearic acid. The molding compacts were obtained under 200 without deficits. Solvent debinding and thermal debinding were combined to remove the binder. The basic magnetic characteristics of the specimen were of the same level as those by powder metallurgy technique, which indicated that to fabricate 2:17 Sm-Co magnets by powder injection molding was feasible. (orig.)

262

Processes at the inetrface molten metal-sand mold  

Directory of Open Access Journals (Sweden)

Full Text Available The processes that take place at the liquid metal-sand mold interface during the casting and crystallization of metal were studied in this paper. The mold was made using the CO2 – method, with the addition of active components, such as: MgO, TiO2, AlK(SO42 and Na2SO4. At the liquid steel pouring temperature, these active components undergo decomposition in the mold, caused by heat release during pouring, crystallization and cooling of castings. Silicates, which have an important influence on casting surface quality, are formed as a result of the interaction between the mould material and liquid steel.

Z. Janjuševi?

2014-04-01

263

CO-INJECTION RESIN TRANSFER MOLDING FOR OPTIMIZATION OF INTEGRAL ARMOR  

Science.gov (United States)

To address the cost and performance barriers which hinder the introduction of composite materials for combat ground vehicle applications, Co-Injection Resin Transfer Molding (CIRTM) and Diffusion Enhanced Adhesion (DEA) have been recently invented and developed at the Army Resear...

264

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

Science.gov (United States)

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

265

Precision compression molding process of low Tg glass aspheric lenses  

Science.gov (United States)

Precision Glass Molding Process is adopted for mass production of aspheric lenses, micro-lens array, diffractive optical elements and free-form lenses which are difficult to be manufactured by using conventional methods. In this research, high order aspheric lenses with 6th item are molded using the glass material P-SK57 which is characterized by a low glass transition temperature (Tg) 493°C and thermal expansion coefficient (TEC) 8.9×10-6. Some of the molding conditions are as follow: 1) the molding temperature is 565°C, 2) the pressure force is kept at 4KN for 90 seconds and 3) the lens is cooling at an annealing velocity of 1.5~2°C /s to a release temperature of 180°C. The total molding cycle time is about 16 minutes. Molded aspheric lenses are measured with a Taylorsurf contact profilometer and a Zygo Newview white-light interferometer. As a result, the shape accuracy of molded lenses is less than 0.5um (PV) and surface finish quality is less than 2nm.

Ma, Tao; Yu, Jingchi

2009-05-01

266

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

Energy Technology Data Exchange (ETDEWEB)

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

David M. Wright; DOE Project Officer - Keith Bennett

2007-07-31

267

Recycling process of casting molds applying to precision castings  

OpenAIRE

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

Drajewicz, M.; Pytel, M.

2012-01-01

268

Study of micropart fabrication via 17-4 PH stainless nanopowder injection molding.  

Science.gov (United States)

Micropart fabrication via 17-4 PH stainless nanopowder injection molding was investigated. The nanopowder was mixed with a binder that was based on wax to produce a feedstock composed of 45% powder and binder (the powder load). Initially, the fit and proper test was done before the micropart was made by making some bars of green samples, which the properties were examined after the sintering process. The examination involved the mechanical properties such as the porosity, hardness, and some of metallurgical aspects, such as the second-phase formation and the final compound after the sintering. The results showed that utilizing 17-4 PH stainless nanopowder is promising for micropart fabrication since it can form a nearly full-density sintered sample with a low porosity and good toughness, and can provide a smooth surface finish. After this, the investigations followed with the injection of the feedstock into the PDMS micromold that was formed by the nickel pattern from the X-Ray LIGA process. The green samples successfully produced a high-aspect-ratio sample with a thickness of up to 1 mm and an aspect ratio of 15 in the microchannel part. Then the green samples were sintered at 1,300 degrees C for 2 h, since from the initial test, they showed optimum parameters with nearly full density, low porosity, and a high degree of hardness. The research shows the excellent results of the application of the 17-4 PH stainless nanopowder to micropart fabrication. PMID:21446435

Tirta, Andy; Prasetyo, Yus; Baek, Eung-Ryul; Choi, Chul-Jin

2011-01-01

269

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

DEFF Research Database (Denmark)

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

Menotti, Stefano; Hansen, Hans NØrgaard

2014-01-01

270

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

271

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 approximatel 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.

272

Modeling and control of flow during impregnation of heterogeneous porous media, with application to composite mold-filling processes  

Science.gov (United States)

Liquid Composite Molding (LCM) encompasses a growing list of composite material manufacturing techniques. These processes have provided the promise for complex fiber reinforced plastics parts, manufactured from a single molding step. In recent years a significant research effort has been invested in development of process simulations, providing tools that have advanced current LCM technology and broadened the range of applications. The requirement for manufacture of larger, more complex parts has motivated investigation of active control of LCM processes. Due to the unlimited variety of part geometries that can be produced, finite element based process simulations will be used to some extent in design of actively controlled processes. Ongoing efforts are being made to improve material parameter specification for process simulations, increasing their value as design tools. Several phenomena occurring during mold filling have been addressed through flow visualization experimentation and analysis of manufactured composite parts. The influence of well defined air channels within a mold cavity is investigated, incorporating their effects within existing filling simulations. Three different flow configurations have been addressed, testing the application of 'equivalent permeabilities', effectively approximating air channels as representative porous media. LCM parts having doubly curved regions require preform fabrics to undergo significant, and varying deformation throughout a mold cavity. Existing methods for predicting preform deformation, and the resulting permeability distribution have been applied to a conical mold geometry. Comparisons between experiment and simulation are promising, while the geometry studied has required large deformation over much of the part, shearing the preform fabric beyond the scope of the models applied. An investigational study was performed to determine the magnitude of effect, if any, on mold filling caused by corners within LCM mold cavities. The molds applied in this study have required careful consideration of cavity thickness variations. Any effects on mold filling due to corner radii have been overshadowed by those due to preform compression. While numerical tools are available to study actively controlled mold filling in a virtual environment, some development is required for the physical equipment to implement this in practice. A versatile, multiple line fluid injection system is developed here. The equipment and control algorithms employed have provided servo control of flow rate, or injection pressure, and have been tested under very challenging conditions. The single injection line developed is expanded to a multiple line system, and shows great potential for application to actual resin systems. A case study is presented, demonstrating design and implementation of a simple actively controlled injection scheme. The experimental facility developed provides an excellent testbed for application of actively controlled mold filling concepts, an area that is providing great promise for the advancement of LCM processes.

Bickerton, Simon

273

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

DEFF Research Database (Denmark)

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

Peltola, Heidi; Madsen, Bo

2011-01-01

274

Evaluation of Mechanical Properties of Injection Molding Composites Reinforced by Bagasse Fiber  

Science.gov (United States)

BMC (Bulk Molding Compound) is composed of UP (Unsaturated Polyester) resin, glass fibers, and bagasse fibers which have been obtained after squeezing sugar cane. Our purpose is to use the bagasse fibers as reinforcement and filler in BMC to fabricate composites by injection molding and injection compression molding. The mechanical properties of injection molding composites were improved after adding the bagasse fibers. Observing the fracture surface of the tensile test specimen through SEM, we could notice the glass fibers were penetrated into the bagasse fibers longitudinally. Along with UP resin solidifying, the glass fibers were firmly fixed in the bagasse fibers and finally united with them. This phenomenon could bring on the same effect as the glass fibers length was prolonged, so that the adhesion interface between fiber and matrix resin became larger, which leads to the increase in the mechanical properties. Otherwise, it was observed that UP resin sufficiently permeated the bagasse fibers and solidified. This also contributes to enhancing the mechanical properties drastically.

Cao, Yong; Fukumoto, Isao

275

Computing flow-induced stresses of injection molding based on PTT model  

International Nuclear Information System (INIS)

A numerical approach is introduced to solve the viscoelastic flow problem of filling and post-filling in injection molding. The governing equations are in terms of compressible, non-isothermal fluid, and the constitutive equation is based on the PTT model. By introducing some hypotheses according to the characteristics of injection molding, a quasi-Poisson type equation about pressure is derived with part integration. Besides, an analytical form of flow-induced stress is also generalized by using Undermined Coefficient Method. The conventional Galerkin approach is employed to solve the derived pressure equation, and the 'upwind' difference scheme is used to discrete the energy equation. Coupling is achieved between velocity and stress by Super Relax Iteration Method. The flow in the test mold is investigated by comparing the numerical results and photoelastic photos for polystyrene, showing flow-induced stresses are closely related to melt temperatures. The filling of a two-cavity box is also studied to investigate the viscoelastic effects on real injection molding.

276

Surface Orientation in Injection-Molded Thermotropic Liquid Crystalline Copolyester (TLCP) Plaques  

Science.gov (United States)

Attenuated total reflection Fourier transform infra-red (ATR-FTIR), C K edge near edge X-ray adsorption fine structure (NEXAFS) spectroscopies, and 2-D WAXS in transmission were used to characterize surface orientation in thermotropic liquid crystalline copolyester (TLCP) injection-molded plaques to varying depths into the samples. Injection-molded TLCPs have bimodal orientation states due to contributions from ``skin'' and ``core'' regions resulting from extensional and shear flow, respectively, in the mold. The NEXAFS is sensitive to the orientation of the molecular pi orbital of backbone phenyl groups of the top 2 nm of a surface. ATR-FTIR obtained using a Herrick Seagull variable angle reflectance accessory is sensitive for dichroic ratios to a depth of 5 microns. Orientation parameters derived from the 1502/cm absorption band for equivalent positions are often typically about 5 to 10 percent less by ATR-FTIR than by NEXAFS. The orientational states are being correlated with physical properties of injection-molded TLCP samples.

Bubeck, Robert; Fang, Jun; Burghardt, Wesley; Burgard, Susan; Robertson, Katherine; Fischer, Daniel

2008-03-01

277

Unique opportunities in powder injection molding of refractory and hard materials  

International Nuclear Information System (INIS)

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

278

Simulation of polymer removal from a powder injection molding compact by thermal debinding  

Science.gov (United States)

Powder injection molding (PIM) is an important net-shape manufacturing process. Thermal debinding is a common methodology for the final removal of residual polymer from a PIM compact prior to sintering. This process is an intricate combination of evaporation, liquid and gas migration, pyrolysis of polymer, and heat transfer in porous media. A better understanding of thermal debinding could lead to optimization of the process to prevent the formation of defects. Simulation of the process based on an integrated mathematical model for mass and heat transfer in porous media is proposed. The mechanisms of mass transport, i.e., liquid flow, gas flow, vapor diffusion, and convection, as well as the phase transitions of polymer, and their interactions, are included in the model. The macroscopic partial differential equations are formulated by volume averaging of the microscopic conservation laws. The basic equations consist of mass conservation and energy conservation and are solved numerically. Polymer residue, pressure, and temperature distributions are predicted. The importance of the various mass transfer mechanisms is evaluated. The effects of key mass transfer parameters on thermal debinding are discussed. It is revealed from the results that the assumed binder front, which is supposed to recede into the powder compact as removal progresses, does not exist. The mass flux of polymer liquid is of the same order of the mass flux of polymer vapor in the gas phase, and the polymer vapor diffusion in the liquid phase is negligible.

Lam, Y. C.; Yu, S. C. M.; Tam, K. C.; Shengjie, Ying

2000-10-01

279

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

Science.gov (United States)

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

Cooper, K. G.

2000-01-01

280

The manufactoring of a two–layered 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. Košnik

2011-10-01

281

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

282

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

Scientific Electronic Library Online (English)

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

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

2005-07-01

283

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

284

Influence of the power law index on the fiber breakage during injection molding by numerical simulations  

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 > 15mm) this investigation concentrates on the influence of the power law index on the final fiber length distribution within the injection molded part. To realize this, the Autodesk Simulation Moldflow Insight Scandium 2013 software has been used. In this software, a fiber breakage algorithm is available from this release on. Using virtual material data with realistic viscosity levels allows to separate the influence of the power law index on the fiber breakage from the other material and process parameters. Applying standard settings for the fiber breakage parameters results in an obvious influence on the fiber length distribution through the thickness of the part and also as function of position in the part. Finally, the influence of the shear rate constant within the fiber breakage model has been investigated illustrating the possibility to fit the virtual fiber length distribution to the possible experimentally available data.

Desplentere, Frederik; Six, Wim; Bonte, Hilde; Debrabandere, Eric

2013-04-01

285

Numerical Method to Predict Void Formation during The Liquid Composite Molding Process  

OpenAIRE

Void formation during the injection phase of the liquid composite molding process can be explained as a consequence of the non-uniformity of the flow front progression. This is due to the dual porosity within the fiber perform (spacing between the fiber tows is much larger than between the fibers within in a tow) and therefore the best explanation can be provided by a mesolevel analysis, where the characteristic dimension is given by the fiber tow diameter of the order of milli...

Dimitrovova?, Zuzana; Advani, Suresh G.

2004-01-01

286

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

Scientific Electronic Library Online (English)

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

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

2007-06-01

287

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

Directory of Open Access Journals (Sweden)

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

Diovani C. Lencina

2007-06-01

288

Inexpensive 3dB coupler for POF communication by injection-molding production  

Science.gov (United States)

POFs (polymer optical fibers) gradually replace traditional communication media such as copper and glass within short distance communication systems. Primarily, this is due to their cost-effectiveness and easy handling. POFs are used in various fields of optical communication, e.g. the automotive sector or in-house communication. So far, however, only a few key components for a POF communication network are available. Even basic components, such as splices and couplers, are fabricated manually. Therefore, these circumstances result in high costs and fluctuations in components' performance. Available couplers have high insertion losses due to their manufacturing method. This can only be compensated by higher power budgets. In order to produce couplers with higher performances new fabrication methods are indispensable. A cheap and effective way to produce couplers for POF communication systems is injection molding. The paper gives an overview of couplers available on market, compares their performances, and shows a way to produce couplers by means of injection molding.

Haupt, M.; Fischer, U. H. P.

2011-01-01

289

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

Directory of Open Access Journals (Sweden)

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

Dong Kwon Park

2013-09-01

290

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

OpenAIRE

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

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

2013-01-01

291

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

OpenAIRE

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

292

Carbon Nanotubes Reinforced Copper Matrix Nanocomposites via Metal Injection Molding Technique  

OpenAIRE

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...

Mohamed, Norani M.; Faiz Ahmad; Muhsan, Ali S.; Yusoff, Putri S. M. Bt M.; Raza, M. R.

2012-01-01

293

Semi-automatic laboratory equipment for reactive injection molding  

OpenAIRE

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

294

Consumable molding process for super alloys  

International Nuclear Information System (INIS)

A method of preparing a charge of super alloy material for use in metal casting is disclosed. Thin wall tubes consisting of one of the metallic elements of the alloy material, or an alloy of such element are provided. If an alloy tube is selected, all elements in the tube alloy must also be materials included in the overall formulation of the alloy material. The type and quantity of the materials contained in the tubes is deducted from the quantities set forth in the overall formula and the balance of the formula is melted and poured under vacuum as a core in the tube using the tube as a mold. The resulting master charge is cut into unit charges each of a predetermined weight. These unit charges are then used in a subsequent casting operation by melting the entire unit charge under vacuum to cast precision products of an alloy which consists of the mixed and alloyed materials of both the tube and the core

295

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2014-05-15

296

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

Science.gov (United States)

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

Hausnerova, Berenika; Sanetrnik, Daniel; Paravanova, Gordana

2014-05-01

297

Minimum Amount of Binder Removal Required during Solvent Debinding of Powder-Injection-Molded Compacts  

Science.gov (United States)

Unsatisfactory dimensional control, distortion, and defects are frequently observed in powder-injection-molded parts, particularly after the solvent and thermal-debinding processing steps. One of the reasons is that the amount of soluble binder removed during the first step, solvent debinding, is not great enough to form interconnected pores throughout the compact, particularly in the core region. Thus, blistering, cracking, and bubbles can form easily during the subsequent thermal debinding. To determine the minimum debinding fraction required for solvent debinding, at which point interconnected pore channels are formed at the center, modeling of the distribution of the remaining soluble binder in the compact was established. The actual distribution, which was obtained by measuring the binder content layer by layer with the soxhelt extraction method, is in good agreement with the model. The modeling, bubble test, and fluorescence dye-penetration analysis show that, regardless of the compact thickness, the minimum bulk debinding fraction needed is consistently approximately 59 pct, yielding a local debinding fraction of 37 pct and a porosity of 8.5 pct at the center. This porosity is close to the value at which pores in a sintered compact transform from open to closed at the beginning of the final stage of sintering.

Fan, Yang-Liang; Hwang, Kuen-Shyang; Wu, Shiau-Han; Liau, Yau-Ching

2009-04-01

298

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

Science.gov (United States)

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

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

2011-01-01

299

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

300

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

301

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

Science.gov (United States)

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 ?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 ?m, and a hardness of 457 HV0.1.

Antusch, S.; Norajitra, P.; Piotter, V.; Ritzhaupt-Kleissl, H.-J.

2011-10-01

302

Wear behavior and mechanical performance of metal injection molded Fe-2Ni sintered components  

International Nuclear Information System (INIS)

The microstructure, mechanical properties, and wear behavior of two key components of a hinge fabricated from a metal injection molding process that was then sintered and heat treated under various conditions were analyzed using an optical microscope, a pin-on-disk tester, an open-closed reciprocal wear tester, and a scanning electron microscope. Optical photomicrograph revealed a serious decarburization in the sintered component, suggesting that an increase in carbon content would be necessary to improve mechanical properties. At the initial stage of the open-closed reciprocal wear test, the obverse inclined planes of both components exhibited plastic deformation and depression. As the number of test cycles increased, an increase in cold welding, metal adhesion, spalling, delamination, and surface fatigue was observed, triggering a decrease in metal thickness, which in turn altered the shape of the components. In this study, the optimal parameters to satisfy commercial application requirements were obtained when the components were carburized at 870 oC for 30 min, quenched in oil, and finally tempered at 250 oC for 1 h.

303

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.mol¹, a crystallinity degree of 60%, a glass transition temperature (Tg), at - 0.8 °C, and a melting temperature at 171 °C. The molecular weight of PCL was 0.8 x 10(5) g.mol-1. Specimens of 70/30 wt. (%) P(3HB)/PCL blends obtained by injection molding showed tensile strength of 21.9 (± 0.4) MPa, modulus of 2.2 (± 0.3) GPa, and a relatively high elongation at break, 87 (± 20)%. DSC analyses of this blend showed two Tg´s, at - 10.6 °C for the P(3HB) matrix, and at - 62.9 °C for the PCL domains. The significant decrease on the Tg of P(3HB) evidences a partial miscibility of PCL in P(3HB). According to the Fox equation, the new Tg corresponds to a 92/8 wt. (%) P(3HB)/PCL composition.

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

2006-03-01

304

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

International Nuclear Information System (INIS)

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 ?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 ?m, and a hardness of 457 HV0.1.

305

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

Science.gov (United States)

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

Ren, Bin; Zhang, Shuyou; Tan, Jianrong

2014-07-01

306

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

International Nuclear Information System (INIS)

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

307

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

Directory of Open Access Journals (Sweden)

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

R. Ibrahim

2010-01-01

308

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

309

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

Scientific Electronic Library Online (English)

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

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

2013-06-01

310

Tool steel quality and surface finishing of plastic molds  

OpenAIRE

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, grin...

Rafael Agnelli Mesquita; Reinhold Schneider

2010-01-01

311

Feature-based non-manifold modeling system to integrate design and analysis of injection molding products  

International Nuclear Information System (INIS)

Current CAE systems used for both the simulation of the injection molding process and the structural analysis of plastic parts accept solid models as geometric input. However, abstract models composed of sheets and wireframes are still used by CAE systems to carry out more analyses more efficiently. Therefore, to obtain an adequate abstract model, designers often have to simplify and idealize a detailed model of a part to a specific level of detail and/or abstraction. For such a process, we developed a feature-based design system based on a non-manifold modeling kernel supporting feature-based multi-resolution and multi-abstraction modeling capabilities. In this system, the geometric models for the CAD and CAE systems are merged into a single master model in a non-manifold topological representation, and then, for a given level of detail and abstraction, a simplified solid or non-manifold model is extracted immediately for an analysis. For a design change, the design and analysis models are modified simultaneously. As a result, this feature based design system is able to provide a more integrated environment for the design and analysis of plastic injection molding parts

312

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

313

Solidification process and infrared image characteristics of permanent mold castings  

Science.gov (United States)

Interdependence between the development of temperature gradients at the solid-liquid interface during solidification of metals and the formation of local defects demands for thermal investigation. In foundry practice thermocouples are used to control the die's overall cooling-rate, but fluctuations in product quality still occur. Capturing FIR- thermograms after opening the die visualizes the state, when most thermal throughput has already flattened the temperature gradients in the mold. Rapid dissipation of heat from liquid metal to the mold during solidification forces further approach of the process investigation by slowing down the heat flux or the use of transparent mold material. Aluminum gravity casting experiments under technical vacuum conditions lead to decelerated solidification by suppression of convection and image sequences containing explicit characteristics that could be assigned to local shrinkage of the casting. Hence relevant clusters are extracted and thermal profiles are drawn from image series, pointing out correlations between feeding performance from the sink heads and the appearance of local defects. Tracing thermal processes in vacuum casting can scarcely be transferred to image data in foundry practice, since only little analogies exist between atmospheric and vacuum casting. The diagnosis of the casting process requires detection of the still closed mold using a transparent silica- aerogel sheet as part of the die. Hereby thermograms of the initial heat input are recorded by adapting a NIR-camera in addition to the FIR-unit. Thus the entire thermal compensation at the joint face for each casting is visualized. This experimental set-up is used for image sequence analysis related to the intermediate casting phases of mold filling, body formation and solidification shrinkage.

Viets, Roman; Breuer, Markus; Haferkamp, Heinz; Kruessel, Thomas; Niemeyer, Matthias

1999-03-01

314

Fabrication of Sr-Ferrite Plastic-Bonded Magnet Rotor by Injection Molding  

Science.gov (United States)

A plastic-bonded strontium-ferrite rotor assembly for brushless dc motors is fabricated by injection molding to produce a four-pole arrangement of anisotropic SrO\\cdot6Fe2O3 plastic-bonded magnets. The resultant rotor has superior magnetic flux density characteristics to a conventional four-pole plastic-bonded rotor. The degree of anisotropy and hence magnetic flux of the magnets is found to be dependent on the injection time, with faster injection times producing magnets with higher flux densities. The proposed fabrication method and rotor design eliminate the need for a magnetic path and dynamic balancing of the rotor. The resultant motor therefore operates at a significantly lower noise level compared to motors based on conventional rotors.

Matsuyama, Yoshihiko

2005-05-01

315

Implementation of Molding Constraints in Topology Optimization  

DEFF Research Database (Denmark)

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

Marx, S.; Kristensen, Anders Schmidt

2009-01-01

316

Microstructural study of duplex stainless steels obtained by powder injection molding  

International Nuclear Information System (INIS)

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

317

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

2014-03-15

318

Reproducibility Study of NiTi Parts Made by Metal Injection Molding  

Science.gov (United States)

Powder metallurgy (P/M) is an attractive manufacturing process for net-shaped NiTi parts considering the limited machinability of NiTi alloys. Nevertheless, the industrial implementation of P/M processing for NiTi alloys is not trivial. To become competitive to manufacturing of NiTi alloys based on established ingot metallurgy, combination of fully pronounced shape memory behavior with sufficient mechanical properties is required. Successful use of P/M technology is strongly influenced by high affinity of NiTi alloys for uptake of oxygen and carbon, which leads to the formation of oxygen-containing Ti2Ni and TiC phases coupled with increase of Ni content in the matrix. In the case of Ni-rich NiTi alloys, this increase leads to a shift of phase transformation temperatures to lower values. Furthermore, precipitation of Ni4Ti3 during cooling from sintering temperature is difficult to avoid. Even if these precipitates might be used to decrease the Ni:Ti ratio of the matrix balancing oxygen and carbon uptake, significant loss of ductility arises, especially in the case of finely dispersed Ni4Ti3 precipitates. In the present work, each step of P/M manufacturing is discussed regarding its influence on the specific properties of NiTi alloys. The work is based on the application of prealloyed, gas atomized NiTi powders. Metal injection molding was used for net-shaped manufacturing of tensile samples, which enabled detailed study of sintering behavior combined with investigation of shape memory and mechanical properties depending on particle size, oxygen and carbon content as well as precipitation of Ni4Ti3 phase.

Bram, M.; Bitzer, M.; Buchkremer, H. P.; Stöver, D.

2012-12-01

319

Fabrication of Micro Gears by Micro-Powder Injection-Compression Molding  

Science.gov (United States)

Micro-spur gears were fabricated by powder injection-compression molding and micro-two-step gears were produced through stacking and sintering of the green parts. Shrinkage of micro-gears by sintering was larger in teeth and with increase of compression pressure, shrinkage was decreased due to increase of density in green parts. Surface roughness of sintered body was reduced to a few hundreds of nanometers by ultrasonic micro-polishing. The joining of green bodies by stacking and sintering was achieved using the pressurized sintering and insert of feedstock powders between both green bodies.

Jang, Jin Man; Lee, Wonsik; Son, Seong-Ho; Ko, Se-Hyun; Kim, Il-Ho

320

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

321

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

Science.gov (United States)

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

Albert, Benedikt; Völkl, Rainer; Glatzel, Uwe

2014-09-01

322

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

Science.gov (United States)

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

Chidley, Matthew Douglas

323

Microstructure and magnetic properties of Fe–50%Ni alloy fabricated by powder injection molding  

International Nuclear Information System (INIS)

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

324

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

Energy Technology Data Exchange (ETDEWEB)

Fe-50%Ni soft magnetic alloys were produced by powder injection molding using carbonyl iron and carbonyl nickel as raw materials. The effects of sintering temperature and time on the microstructure and magnetic properties of the alloys were investigated. The results indicate that the magnetic properties are dependent on the microstructure. The densification and grain size of the alloys increase with increasing sintering temperature and time, facilitating the enhancement of permeability and saturation induction, as well as the decrease of coercive force. In the case of the sintering temperature of 1360 Degree-Sign C for 10 h, the relative density of 97% and grain size of 200 {mu}m were obtained, and the maximum permeability of 43,541, saturation induction of 1.48 T and coercive force of 6.8 A/m were achieved. Further elongation of sintering time did not bring about any increase of densification and grain size. - Highlights: Black-Right-Pointing-Pointer High-performance Fe-50%Ni alloy was produced by powder injection molding. Black-Right-Pointing-Pointer The magnetic properties were found to be closely related to density and grain size. Black-Right-Pointing-Pointer The sintering parameters of Fe-50%Ni alloy were optimized.

Ma, Jidong [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Qin, Mingli, E-mail: mlqin75@hotmail.com [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Lin; Zhang, Ruijie; Qu, Xuanhui [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

2013-03-15

325

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

326

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

327

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

328

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.

Østergaard, Peter Friis; Matteucci, Marco

2013-01-01

329

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

Science.gov (United States)

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

Yang, Seunghwa; Yu, Suyoung; Cho, Maenghyo

2014-05-01

330

Correlation of Microstructure with Hardness, Wear Resistance, and Corrosion Resistance of Powder-Injection-Molded Specimens of Fe-Alloy Powders  

Science.gov (United States)

In this study, the powder injection molding (PIM) process was applied to Fe-alloy powders. Microstructure, hardness, wear resistance, and corrosion resistance of the PIM specimens were analyzed and compared with those of a conventional stainless steel, SS316L. When Fe-alloy powders were injection molded and then sintered at 1200 °C or 1250 °C, completely densified specimens with almost no pores were obtained. They contained 63 to 80 vol pct of hard (Cr,Fe)2B dispersed in the austenite or martensite matrix. Since these (Cr,Fe)2B borides were very hard, thermally stable, and corrosion resistant, hardness, high-temperature hardness, wear resistance, and corrosion resistance of the PIM specimens of Fe-alloy powders were 2 to 5 times as high as those of the stainless steel. Such property improvement suggested new applicability of the PIM products of Fe-alloy powders to structures and parts requiring excellent mechanical properties.

Son, Chang-Young; Yoon, Tae Shik; Lee, Sunghak

2009-05-01

331

Development of homogeneous filling method of particulate materials into compression mold for nuclear fuel process  

International Nuclear Information System (INIS)

In order to improve the production technology of mixed oxide of plutonium and uranium (MOX) pellets for Fast Breeder Reactor (FBR), the applicability of particle simulation to optimize mold-filling process, instead of trial and error experiments, was investigated. The mold-filling simulation was prepared employing large scale Distinct Element Method (DEM), which has been developed in powder technology. The DEM simulation was conducted using physical properties of tungsten trioxide (WO3) granules, which are model of MOX granules, and compared with results of mold-filling experiments with WO3 granules. The simulation could well represent the mold-filling behavior, and estimate the degree of segregation in the mold. It was found that the segregation in feeding container and the flow behavior of granules filled into the mold influences much on the packed structure of granules in the mold. The DEM is expected to be a powerful tool to optimize MOX fuel production process. (author)

332

Internal stresses analysis in electroformed nickel shells for thermoplastics injection mold core (rapid tooling)  

International Nuclear Information System (INIS)

This study deals with a research field started at the LFI laboratorio de Fabricacion Integrada) of the ULPGC (Universidad de Las Palmas de Gran Canaria). Its aim is to analyse and propose improvements in the electroformed nickel cores manufacture. The main application of these cores is to be used as plastic injection molds. It has been considered an important part of this study taking under consideration internal stresses that appear in the nickel electroformed core. These stresses play a determinant role towards reaching a dimensional and resistant quality standard of the shells, which will be later transformed into cores. The investigation includes not only a theoretic study but also an experimental one. the testing method has the remarkable advantage of a wide industrial application because of its simplicity, low cost and reproducibility of the electrolytic bath actual conditions. (Author) 7 refs

333

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

International Nuclear Information System (INIS)

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 ?10 mm x 7 mm. Typical data of magnetic properties are as follows: B r = 0.72 T, H CJ = 796 kA/m and (BH)max 94.7 kJ/m3. The density is 4.79 Mg/m3. 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

334

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

335

INJECTION MOLDING AND STRUCTURAL ANALYSIS IN METAL TO PLASTIC CONVERSION OF BOLTED FLANGE JOINT BY CAE  

Directory of Open Access Journals (Sweden)

Full Text Available Many metal parts in various applications are being replaced by plastic parts. There are several reasons for that depending on actual application - minimize part cost, enhance corrosion resistance, integrating more components into one part etc. Most important steps of metal to plastic conversion are material selection and design of plastic part. Plastic part has to withstand the same load as metal part. To fulfill this requirement fiber reinforced engineering plastics are often used. Also it is convenient to substitute heavy wall sections with ribbed structure to increase load-carrying ability of part and decrease cycle time, eliminate voids, sink marks etc. Mechanical properties of such part could be highly affected by fiber orientation. Results of fiber orientation from injection molding filling analysis can be used in stress analysis for better prediction of part response to mechanical load. Such coupled analysis is performed here in this case study on bolted flange joint.

Marian Blaško

2014-12-01

336

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

Science.gov (United States)

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

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

2013-03-01

337

A study on phases change of Ti-Mn alloys produced by metal injection molding  

Science.gov (United States)

The phases change of a set of Ti-Mn alloys produced by powder metal injection molding technique (MIM) is studied in the present work. The materials were received in the as sintered condition (1100 °C for 8 hours), then subjected to solution treatment and aging. In the as sintered condition, ?-phase is the predominant phase. After solution treatment, full homogenized ?-phase was obtained in the high Mn-content alloys, while, ?'-phase is predominant in the high or low Mn-content alloys. Very fine ?-phase precipitated predominately by aging at 500 °C and 560 °C, while isothermal ?-phase precipitated by aging at 400 °C for short times. The isothermal ?-phase retransformed to ?-phase after aging for longer times.

Gouda, Mohammed K.; Gepreel, Mohamed A. H.; El Moniem, A. Abd

2013-12-01

338

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

Science.gov (United States)

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.

Ødegaard Andresen, Kristian; Hansen, Morten; Matschuk, Maria; Terpager Jepsen, Søren; Schiøtt Sørensen, Henrik; Utko, Pawel; Selmeczi, Dávid; Hansen, Thomas S.; Larsen, Niels B.; Rozlosnik, Noemi; Taboryski, Rafael

2010-05-01

339

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

340

Easy alignment and effective nucleation activity of ramie fibers in injection-molded poly(lactic acid) biocomposites.  

Science.gov (United States)

The poly(lactic acid) (PLA)/ramie fiber biocomposites were fabricated, which exhibited considerable reinforcement effect comparable to the glass fiber at the same loading. The attempts were made to understand the flow-induced morphology of ramie fibers and PLA crystals in the injection-molded PLA/ramie fiber biocomposites, thus revealing its relationship to biocomposite mechanical properties. The polarized optical microscopy (POM) and two-dimensional wide-angle X-ray diffraction (2D-WAXD) were for the first time used to determine the distribution of nature fibers, which interestingly showed the ramie fibers aligned well along the flow direction over the whole thickness of injection-molded parts, instead of skin-core structure. This easy alignment of ramie fibers during the common processing was ascribed to the intrinsically high flexibility of ramie fibers and strong interfacial interaction between PLA chains and cellulose molecules of ramie fibers. Both 2D-WAXD and differential scanning calorimeter (DSC) measurements suggested that the PLA matrix in its ramie biocomposites had rather high orientation degree and crystallinity, which was attributed to effective heterogeneous nucleation induced by ramie fibers and local shearing field in the vicinity of fiber surface. Remarkable improvement of mechanical and thermo-mechanical properties was achieved for PLA/ramie fiber biocomposites, without sacrifice of toughness and ductility. Addition of 30wt% ramie fibers increased the tensile strength and modulus of PLA/ramie fiber biocomposites from 65.6 and 1468 MPa for pure PLA to 91.3 and 2977 MPa, respectively. These superior mechanical properties were ascribed to easy alignment of ramie fibers, high crystallinity of PLA, and favorable interfacial adhesion as revealed by scanning electron microscopy (SEM) observation and theoretical analysis based on dynamic mechanical analysis (DMA) data. PMID:22806502

Xu, Huan; Liu, Chun-Yan; Chen, Chen; Hsiao, Benjamin S; Zhong, Gan-Ji; Li, Zhong-Ming

2012-10-01

341

Research of thermal response simulation and mold structure optimization for rapid heat cycle molding processes, respectively, with steam heating and electric heating  

International Nuclear Information System (INIS)

The dynamic mold temperature control system is the key of rapid heat cycle molding (RHCM) technology because it significantly affects the stability of the process, productivity and the quality of the final polymer part. For this reason, the approaches and techniques for dynamic mold temperature control were discussed in this study and two different dynamic mold temperature control methods, respectively, with steam heating and electric heating were found to be very feasible in mass production. The methods and principles of mold design for the two RHCM technologies were also discussed and then several different kinds of mold structures were designed. By constructing the corresponding thermal response analytical models for these RHCM molds, the temperature responses of the molding systems in the heating and cooling process of RHCM were simulated and studied. The effects of the mold design parameters such as the insulation layer between mold plate and mold inert, and mold material, on thermal response efficiency and temperature uniformity of the two RHCM processes were analyzed based on the simulation results. The results show that the insulation layer can increase the upper limit temperature of RHCM with steam heating and improve the heating speed of RHCM with electric heating. It can also greatly decrease the energy consumption of the two RHCM processes. The heating efficiency of RHCM with steam heating can be effectively improved by increasing the thermal conductivity of the cavity/core material, while the situation is diametrically opposite for RHCM with electric heating. Therefore, we acquired an optimized mold design principle and method for RHCM with steam heating and electric heating, respectively. Finally, a new electric heating mold with a cooling plate was proposed to enhance the cooling efficiency. The thermal response of this new electric heating mold was also simulated. The simulation results show that the cooling plate can significantly improve the cooling and heating efficiency.

342

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

343

Hybrid tooling technologies and standardization for the manufacturing of inserts for micro injection molding  

DEFF Research Database (Denmark)

This paper is based on the European Platform’s activities within the 4M Network of Excellence “Multi-Material Micro Manufacturing”. To overpass limitations of the current existing micro tooling capabilities, a new generation of micro hybrid tooling technologies for micro replication was developed. A metrological approach was applied to standardize the employed tooling processes (micro milling, µEDM, laser micromachining, electrochemical µ-milling). The micro tools were then tested with different polymers (PP, PP + nano fillers, PC, COC). The paper provides a comparison of these technologies concerning obtainable feature sizes, surface finish, and aspect ratios of both micro tools and micro molded parts.

Tosello, Guido; Fillon, Bertrand

2007-01-01

344

An opto-chemical assay for mold detection in processing tomatoes  

Science.gov (United States)

Fungal (mold) contamination is an important indicator of low quality raw product or unsanitary processing conditions in the food industry. A quantitative lectin assay was developed that was less expensive, faster, and more precise than the industry standard Howard mold count. This assay, based on a fluorescent-labeled lectin isolated from wheat germ, has a selective affinity for the chitin in fungal cell walls. Assay values had high linear correlations (from r 2 = .72 to r2 = .99) with fungal biomass for ten fungal species of greatest importance to the California processing tomato industry. One hundred raw tomato juice samples with natural mold infections were collected, as part of the normal California processing tomato inspection program, from commercial processing tomato loads. The raw juice samples were sent to four processor quality control laboratories, where an industry standard Howard mold count was conducted on blind triplicates of each of the samples. The lectin assay was also conducted on blind replicates of the raw juice samples. The correlation between the lectin assay and the Howard mold count (r = .85) was as strong as the correlation between the Howard mold counts for two facilities. The assay had significantly better (alpha = .01) precision than the Howard mold count, with an average coefficient of variation of 8%, compared with 38% for the Howard mold count. The assay is objective, can be conducted in under six minutes, and has the potential to replace mold testing in both raw and processed products.

Potts, Steven James

345

Rubber molds for investment casting  

International Nuclear Information System (INIS)

The main objective of the project is to investigate different types of molding rubbers used for investment casting. The level of shape complexity which can be achieved by using these rubber molds is also studied. It was almost impossible to make complex shapes molds using metal molds, in that cases rubber molds are very important because they arc flexible and give accurate and precise part dimensions. Turbine blades are hi-tech components with air-foil geometries that have close dimensional tolerances. They are made of super-alloys and manufactured by investment casting. The final blade profile depends upon the dimensional accuracy in each of the processing steps. In the present work experimental study for the production of high quality low cost castings of turbine blades using rubber molds and injected wax patterns is presented. Natural Rubber molds and wax patterns from these molds were made. Different types of molding rubbers were studied including natural rubber, silicone rubber and liquid silicone rubber. It was found that by using rubber molds we can make most complex shape with very less finishing required. The shrinkage was 12% as compared to original master pattern. Rubber molds were made using laboratory hot press. Three layers of rubber above and below the master pattern. After that vulcanization was done by giving temperature and pressure. (author)

346

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

347

Determinação da redução da resistência à tração em corpos de prova com Weld Line / Determination of reduction of the weld line strength in injection molded  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Neste trabalho objetivou-se determinar a redução da resistência à tração de corpos de prova com linhas de solda. Os corpos de prova ASTM foram moldados pelo processo de injeção com diferentes temperaturas de plastificação (180 ºC a 280 ºC). O material utilizado foi o polímero termoplástico Polystyro [...] l 158 K da Basf. Este estudo relaciona as linhas de solda em produtos moldados por injeção com a redução da resistência mecânica devido a fragilização na região da linha de solda. Para o desenvolvimento deste trabalho foi projetado e desenvolvido um molde de injeção com uma cavidade em forma de corpo de prova com canal de ataque pelas extremidades. Desta forma no momento da junção dos fluxos obtêm-se uma linha de solda no centro do corpo de prova. Os parâmetros do processo de injeção foram determinados a partir de um aplicativo comercial. A temperatura do molde e o tempo de injeção permaneceram constantes. O tempo de solidificação do material foi determinado analiticamente, considerando-se o centro do corpo de prova como referência. Foram injetados dez corpos de prova em cada uma das temperaturas. Foi observada de forma clara a existência de linhas de junção no centro da peça e as condições de processo utilizadas não permitiram a formação de linha de solda fria. Após a realização dos ensaios de tração, foi determinado que a tensão de ruptura decresce nas seguintes condições: com a diminuição da temperatura de injeção e do tempo de solidificação e com o aumento da trinca. A ruptura sempre ocorreu na linha de solda. Abstract in english In this paper, the purpose is to determine the weld line strength in injection molded samples. The ASTM standard dogbone-shaped samples were molded over a range of melt temperatures (180 ºC up to 280 ºC). The plastic used was a commercial grade of polystyrene (PS), BASF Polystyrol 158K. This study l [...] inks weld lines in parts by injection molding with mechanical strength reduction due to embrittling effect in weld-line region. A single-cavity mold double-gated was used to generate ASTM D638 Type I tensile specimens. The double-gated and runner allow the parts to be molded with weld line. The injection process parameters were determined by imputing resin, machine and geometry information into a CAE software package. The mold temperature and fill time were maintaining the same. The frozen time was determined by analytic equation, which considers the center of the thickness as reference. For each melt temperature 10 samples were tested. The weld line was clearly noted in the centre of the samples and the process condition set avoided the cold weld line. By the strength tests were possible to realize that lower the injection temperature lower the frozen time and higher the length of the crack. Then low injection temperature leads to low maximum strength. The fracture always occurs in the weld line.

R.P., Bom; A.F., Kalin.

2008-06-01

348

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

OpenAIRE

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...

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

2003-01-01

349

Effect of boron addition on injection molded 316L stainless steel: mechanical, corrosion properties and in vitro bioactivity.  

Science.gov (United States)

The research was investigated the effect of boron additions on sintering characteristics, mechanical, corrosion properties and biocompatibility of injection molded austenitic grade 316L stainless steel. Addition of boron is promoted to get high density of sintered 316L stainless steels. The amount of boron plays a role in determining the sintered microstructure and all properties. In this study, 316L stainless steel powders have been used with the elemental NiB powders. A feedstock containing 62.5 wt% powders loading was molded at different injection molded temperature. The binders were completely removed from molded components by solvent and thermal debinding at different temperature. The debinded samples were sintered at different temperature for 60 min. Mechanical property, microstructural characterization and electrochemical property of the sintered samples were performed using tensile testing, hardness, optical, scanning electron microscopy and electrochemical corrosion experiments. Sintered samples were immersed in a simulated body fluid (SBF) with elemental concentrations that were comparable to those of human blood plasma for a total period of 15 days. Both materials were implanted in fibroblast culture for biocompatibility evaluations were carried out. Results of study showed that sintered 316L and 316L with NiB addition samples exhibited high mechanical and corrosion properties in a physiological environment. Especially, 316L with NiB addition can be used in some bioapplications. PMID:23114463

Bayraktaroglu, Esra; Gulsoy, H Ozkan; Gulsoy, Nagihan; Er, Ozay; Kilic, Hasan

2012-01-01

350

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

Science.gov (United States)

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 400 °C (673 K) with a pulse duration of 1 ms and an absorbed power density of up to 1.13 GW/m2. 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.; Blagoeva, D.; Opschoor, J.

2013-11-01

351

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

352

Microstructures and mechanical properties of powder injection molded Ti-6Al-4V/HA powder.  

Science.gov (United States)

Taguchi method with an L9 orthogonal array was employed to investigate the sintered properties of Ti-6Al-4V/HA tensile bars produced by powder injection molding. The effects of sintering factors at the 90% significance level: sintering temperature (1050 degrees C, 1100 degrees C and 1150 degrees C), heating rate (5 degrees C/min, 7.5 degrees C/min and 10 degrees C/min), holding time (30, 45 and 60 min) and cooling rate (5 degrees C/min, 20 degrees C/min and 40 degrees C/min) were investigated. Results showed that sintering temperature, heating rate and cooling rate have significant effects on sintered properties, whereas the influence of holding time was insignificant. It was found that a sintering temperature of 1100 degrees C, a heating rate of 7.5 degrees C/min and a cooling rate of 5 degrees C/min increased the relative density, Vicker's microhardness, flexural strength and flexural modulus. However, a further increment of sintering temperature to 1150 degrees C did not show any discernable improvement in the relative density and Vicker's microhardness, but there was a slight increase of 0.6% and 0.9% in the flexural strength and flexural modulus, respectively. Mechanically strong Ti-6Al-4V/HA parts with an open porosity of around 50% were developed. PMID:12069334

Thian, E S; Loh, N H; Khor, K A; Tor, S B

2002-07-01

353

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

354

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%Y{sub 2}O{sub 3} produced via powder injection molding (PIM)). Therefore, repetitive ELM (edge localized mode)-like loads (n = 100) were applied by means of an electron beam at various temperatures between RT and 400 °C (673 K) with a pulse duration of 1 ms and an absorbed power density of up to 1.13 GW/m{sup 2}. The microstructural properties, e.g. grain size, and Y{sub 2}O{sub 3}-particle distribution, were correlated with crack formation at a certain temperature, the crack propagation direction towards the bulk material and the amount of plastic deformation/surface roughening at higher temperatures. Thereby, it was shown that W–1 vol%Y{sub 2}O{sub 3} outperformed all other investigated grades and reference materials from literature.

Pintsuk, G., E-mail: g.pintsuk@fz-juelich.de [Forschungszentrum Jülich, EURATOM-Association, D-52425 Jülich (Germany); Blagoeva, D. [Nuclear Research and Consultancy Group, P.O. Box 25, 1755 ZG Petten (Netherlands); Opschoor, J. [ECN, Energy research Centre of the Netherlands, P.O. Box 1, 1755 ZG Petten (Netherlands)

2013-11-15

355

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

International Nuclear Information System (INIS)

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 400 °C (673 K) with a pulse duration of 1 ms and an absorbed power density of up to 1.13 GW/m2. 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

356

Investigation of final-stage sintering of various microsize structures prepared by micro powder injection molding  

Science.gov (United States)

Micro powder injection molding ( ?PIM) has been developed as a potential technique for mass production of microcomponents in microsystems due to its shaping complexity at low cost, in which sintering is a crucial step to dictate the final properties of the microcomponents. In this paper, final-stage sintering behavior of 316L stainless steel microsize structures prepared by ?PIM, ?100 ?m and ?60 ?m, respectively, was studied. The effect of size reduction in the regime of micrometers on the density of various microsize structures was investigated. Sintering kinetics of the microsize structures of ?100 ?m and ?60 ?m were studied based on particle level sintering models. It is found that the microsize structures of ?60 ?m had higher density than the microsize structures of ?100 ?m given the same sintering condition. The results indicate that size reduction in the regime of micrometers facilitated densification of microsize structures. The grain growth mechanism of microsize structures varied with size. Whereas the grain growth of the microsize structures of ?100 ?m is governed by surface-diffusion-controlled pore drag, the grain growth of the microsize structures of ?60 ?m is controlled by boundary diffusion. During densification, the microsize structures, ?100 ?m and ?60 ?m, are both controlled by lattice diffusion. The corresponding activation energies are reported in the paper.

Liu, L.; Loh, N. H.; Tay, B. Y.; Tor, S. B.; Yin, H. Q.; Qu, X. H.

2011-06-01

357

Injection molding of ceramic filled polypropylene: The effect of thermal conductivity and cooling rate on crystallinity  

International Nuclear Information System (INIS)

Highlights: • BN, talc and TiO2 in 30 vol% were compounded with polypropylene matrix. • According to the DSC measurements, the fillers are good nucleating agents. • The thermal conductivity of the fillers influences the cooling rate of the melt. • The higher the cooling rate is, the lower the crystallinity in the polymer matrix. - Abstract: Three different nano- and micro-sized ceramic powders (boron-nitride (BN), talc and titanium-dioxide (TiO2)) in 30 vol% have been compounded with a polypropylene (PP) matrix. Scanning electron microscopy (SEM) shows that the particles are dispersed smoothly in the matrix and larger aggregates cannot be discovered. The cooling gradients and the cooling rate in the injection-molded samples were estimated with numerical simulations and finite element analysis software. It was proved with differential scanning calorimetry (DSC) measurements that the cooling rate has significant influence on the crystallinity of the compounds. At a low cooling rate BN works as a nucleating agent so the crystallinity of the compound is higher than that of unfilled PP. On the other hand, at a high cooling rate, the crystallinity of the compound is lower than that of unfilled PP because of its higher thermal conductivity. The higher the thermal conductivity is, the higher the real cooling rate in the material, which influences the crystallization kinetics significantly

358

Quality Prediction Model of Injection-Molded Rib Design using Back-Propagation Network  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, an analytical model of a rectangular thermoplastic ABS (Acrylonitrile Butadiene Styrene plastic cover with rib of a given thickness (2.8 mm was introduced and the dimensions as well as width of the rib were selected as the control factors for simulation. Additionally, the deflection under a constant force of 150 Newton at the back centre of the cover was defined as quality characteristic. Moreover, the L9(34 orthogonal array for four factors and three levels from Taguchi method was additionally considered to layout the 34 = 81 sets of full simulations. By commencing the BPN (Back-Propagation Network to learn the selected 45 sets of simulated results. The remaining 36 sets of simulated results are then employed to verify and construct a quality predictor of rib design. Considering the learning rate as 1 and momentum factor as 0.5, the results of 20000 times of BPN training through a hidden layer indicated that the accuracy of deflection prediction reached 95.87%. In this study, the full FEM (Finite Element Method simulated results from the 81 sets of combinations layout by Taguchi method are learned and verified by BPN for the design of injection-molded rib. It is shown that the quality of a plastic rib can surely be effectively found with the proposed economic and prospective BPN. This study exactly contributes an economical technique to the quality prediction of rib design for plastic injection industry in minimizing the development period of a new product.

Tian-Syung Lan

2009-01-01

359

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

Directory of Open Access Journals (Sweden)

Full Text Available A dificuldade de usinagem de peças cerâmicas já sinterizadas é muito grande, principalmente devido à dureza e fragilidade destes materiais, o que implica em altos custos de produção. Por isso, grandes esforços tem sido feitos no sentido de melhorar os processos de conformação a verde existentes, ou criar novos processos que permitam a obtenção de peças cada vez mais próximas do formato final desejado. Produzir peças cerâmicas com formatos complexos, livres de defeitos, é uma tarefa que implica em grandes dificuldades. Molas cerâmicas possuem formatos extremamente difíceis de serem moldados e, conseqüentemente, atualmente são produzidas comercialmente molas cerâmicas pelo processo de usinagem, geralmente a um custo elevado. Uma alternativa para a produção de molas cerâmicas é a moldagem por injeção em baixa pressão. Para o desenvolvimento de molas cerâmicas para aplicações tecnológicas, é necessário, além de obter peças íntegras e livres de defeitos, aferir algumas de suas propriedades, como a constante de mola. Uma vez que estas molas encontram aplicação em altas temperaturas, torna-se imprescindível realizar a medida da resistência imposta pela mola à deformação elástica em diferentes temperaturas. Para tanto, este trabalho propõem a montagem de um sistema para a medição da constante de mola de molas cerâmicas injetadas a baixa pressão, tanto à temperatura ambiente como em altas temperaturas, usando o método dinâmico da excitação por impulso para medir a frequência de vibração da mola suspensa no interior de um forno. Para ilustrar a aplicação desta técnica são apresentados resultados obtidos para uma mola helicoidal de alumina, da temperatura ambiente até 1100 ºC.The machining of sintered ceramic parts is a difficult process, mainly due to the hardness and brittleness of these materials, which implies in high production costs. Therefore, great efforts have been made to improve the forming processes of green ceramics, or create new processes to obtain the near net shape parts. The production of ceramic parts with complex shapes, free of defects, is a task that involves great difficulties. Ceramic springs exhibits shapes extremely difficult to be molded and therefore are currently commercially produced mainly by machining, a process which is difficult and expensive. An alternative for the production of ceramic springs is by low-pressure injection molding. For the development of ceramic springs for technological applications, it is required in addition to getting parts intact and free of defects, to measure some of its properties, including the spring constant. Since these springs are usually applied at high temperatures, it becomes important to carry out the measurement of resistance imposed by the spring to elastic deformation at different temperatures. Accordingly, in this work we describe the assembly of an experiment for the measurement of the spring constant of low-pressure injection molded ceramic springs, both at ambient temperature and at high temperatures, using the dynamic impulse excitation method to measure the frequency of vibration of a suspended spring inside a furnace. Results are presented for a helical spring of alumina from room temperature to1100 ºC to illustrate the application of this technique.

R. A. Barbieri

2011-12-01

360

On the effect of the fiber orientation on the flexural stiffness of injection molded short fiber reinforced polycarbonate plates  

OpenAIRE

The through-thickness fiber orientation distribution of injection molded polycarbonate plates was experimentally determined by light reflection microscopy and manual digitization of polished cross sections. Fiber length distribution was determined by pyrolysis tests followed by image analysis. A statistical analysis was done to determine the confidence limits of the fiber orientation results. The fiber orientation distribution was described by using second-order orientation ten...

Neves, N. M.; Isdell, G.; Pouzada, A. S.; Powell, P. C.

1998-01-01

361

Unique crystal morphology and tensile properties of injection-molded bar of LLDPE by adding HDPE with different molecular weights  

International Nuclear Information System (INIS)

In this research, a linear low density polyethylene (LLDPE) was first melt blended with a series of high density polyethylenes (HDPE) with different molecular weights at a fixed ratio of LLDPE/HDPE = 90/10 (w/w). The prepared HDPE/LLDPE blends were then injection-molded into specimen bars through a dynamic packing injection molding (DPIM) technique, in which an oscillating shear field was imposed on the melt by two pistons that move reversibly with the same frequency during the packing stage. The crystal morphology, orientation and tensile properties were characterized by scanning electron microscopy, two-dimensional wide-angle X-ray scattering and Instron, respectively. Compared with conventional injection molding, DPIM caused an obvious increase in tensile strength in the injection-molded bars. Interestingly, LLDPE blended with low molecular weight HDPE (LMW-PE) was found to possess much higher tensile strength than that blended with high molecular weight HDPE (HMW-PE). Shish-kebab morphology was observed for all blends obtained, regardless of the molecular weight of the HDPE. However, thicker but shorter lamellae were observed for the LLDPE/LMW-PE blend, corresponding to a higher melting temperature; while thinner but longer lamellae were seen for the LLDPE/HMW-PE blend, corresponding to a lower melting temperature. Furthermore, the phase miscibility between HDPE and LLDPE was found to increase with increasing HDPE molecular weight, which would affect the sensitivir weight, which would affect the sensitivity of molecular chains for response to external shear. The changed miscibility, together with the changed entanglement density in different HDPE was responsible for the change in tensile strength and unique crystal morphology of LLDPE induced by adding HDPE

362

Development of a compression molding process for three-dimensional tailored free-form glass optics.  

Science.gov (United States)

Because of the limitation of manufacturing capability, free-form glass optics cannot be produced in a large volume using traditional processes such as grinding, lapping, and polishing. Very recently compression molding of glass optics became a viable manufacturing process for the high-volume production of precision glass optical components. An ultraprecision diamond-turning machine retrofitted with a fast tool servo was used to fabricate a free-form optical mold on a nickel-plated surface. A nonuniform rational B-spline trajectory generator was developed to calculate the computer numerical control machine tool path. A specially formulated glass with low transition temperature (Tg) was used, since the nickel alloy mold cannot withstand the high temperatures required for regular optical glasses. We describe the details of this process, from optical surface geometry, mold making, molding experiment, to lens measurement. PMID:16912790

Yi, Allen Y; Huang, Chunning; Klocke, Fritz; Brecher, Christian; Pongs, Guido; Winterschladen, Markus; Demmer, Axel; Lange, Sven; Bergs, Thomas; Merz, Michael; Niehaus, Frank

2006-09-01

363

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

364

Analysis of Optimal Injection Moulding Process Parameters for Thin-Shell Plastic Product Using Response Surface Methodology  

OpenAIRE

The injection molding process is used to produce thin-walled plastic products for a wide variety of applications. However, the difficulty in adjusting optimum process parameters setting may cause defects on injected moulded parts such as shrinkage. A study was conducted for the determination of the optimal injection moulding process parameters which will minimize the shrinkage defect on a thin-shell plastic product for cell phone housing component. The machine process setting in use currently...

Awang Bono; Jumat Sulaiman; Rajalingam, S.

2014-01-01

365

Effect of mixing on the rheology and particle characteristics of tungsten-based powder injection molding feedstock  

International Nuclear Information System (INIS)

This study investigates the effect of mixing technique and particle characteristics on the rheology and agglomerate dispersion of tungsten-based powder injection molding (PIM) feedstock. Experiments were conducted with as-received (agglomerated) and rod-milled (deagglomerated) tungsten powder mixed in a paraffin wax-polypropylene binder. Increase in the mixing shear rate decreased the agglomerate size of the agglomerated tungsten powder, decreased the viscosity, and improved the flow stability of the feedstock, interpreted as increased homogeneity of the feedstock. Higher solids volume fraction, lower mixing torques, and improved homogeneity were observed with deagglomerated tungsten powder, emphasizing the importance of particle characteristics and mixing procedures in the PIM process. Hydrodynamic stress due to mixing and the cohesive strength of the tungsten agglomerate were calculated to understand the mechanism of deagglomeration and quantify the effect of mixing. It was concluded that deagglomeration occurs due to a combination of rupture and erosion with the local hydrodynamic stresses exceeding the cohesive strength of the agglomerate

366

Effect of Fe or Cr Addition on the Strengthening Ti-6Al-4V Alloy by Metal Injection Molding  

Science.gov (United States)

It has been found that the strengthening of sintered Ti-6Al-4V alloy compacts were available by addition of fine Mo powder, because of microstructural modification on the sintered compacts. In this study, the metal injection molding process has been applied to strengthen Ti-6Al-4V alloy compacts by addition of fine Fe or Cr powders. Fe and Cr are the same beta stabilizing element as Mo and are more cost effective powders as compared to Mo powder. The microstructures of sintered compacts were consisted of acicular alpha phases and intergranular beta phases. The tensile strength of sintered compacts was increased with increasing Fe or Cr contents, and the effect of Fe addition for strengthening the sintered compacts was larger than Cr addition. Eventually, the tensile strength of sintered compacts added 2mass% of Fe was improved to be 980MPa with 14.8% of elongation, and the compacts added 4mass% of Cr showed the excellent tensile strength of 1030MPa with 15.1% of elongation.

Itoh, Yoshinori; Miura, Hideshi; Uematsu, Toshiaki; Osada, Toshiko; Sato, Kenji

367

Permeability Tests of Fiber Fabrics in the Vacuum Assisted Resin Transfer Molding Process  

Science.gov (United States)

A special device is designed to measure the in-plane and through-thickness permeability of a preform for the vacuum assisted resin transfer molding (VARTM) process. The device is composed of pressure control module, aluminum experimental platform, thickness test module, and pressure test module, which is controlled by a computer. Two kinds of experiments were conducted for carbon fiber noncrimp biaxial fabrics to verify the reliability of the new device based on constant pressure injection. The two experiments are composed of: (1) testing of in-plane permeability for 1, 5, 10 and 20 layers with the method of the line injection by comparing the two conventional methods; (2) testing of the through-thickness permeability for the laminate denoted as [±45] 20 with the central injection method. The results show: (1) the in-plane permeability decrease with the increase of layer number and the permeability for 20 layers is only 62 % of the one layer; (2) the in-plane permeability is an order of magnitude greater than through-thickness permeability based on experimental results of laminate denoted as [±45] 20. A good agreement obtained between the device and two comparison methods proves the validity of the device.

Changchun, Wang; Guanghui, Bai; Yang, Wang; Boming, Zhang; Lijian, Pan

2014-08-01

368

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

369

Tribological and mechanical performance evaluation of metal prosthesis components manufactured via metal injection molding.  

Science.gov (United States)

The increasing number of total joint replacements, in particular for the knee joint, has a growing impact on the healthcare system costs. New cost-saving manufacturing technologies are being explored nowadays. Metal injection molding (MIM) has already demonstrated its suitability for the production of CoCrMo alloy tibial trays, with a significant reduction in production costs, by holding both corrosion resistance and biocompatibility. In this work, mechanical and tribological properties were evaluated on tibial trays obtained via MIM and conventional investment casting. Surface hardness and wear properties were evaluated through Vickers hardness, scratch and pin on disk tests. The MIM and cast finished tibial trays were then subjected to a fatigue test campaign in order to obtain their fatigue load limit at 5 millions cycles following ISO 14879-1 directions. CoCrMo cast alloy exhibited 514 HV hardness compared to 335 HV of MIM alloy, furthermore it developed narrower scratches with a higher tendency towards microploughing than microcutting, in comparison to MIM CoCrMo. The observed fatigue limits were (1,766 ± 52) N for cast tibial trays and (1,625 ± 44) N for MIM ones. Fracture morphologies pointed out to a more brittle behavior of MIM microstructure. These aspects were attributed to the absence of a fine toughening and surface hardening carbide dispersion in MIM grains. Nevertheless, MIM tibial trays exhibited a fatigue limit far beyond the 900 N of maximum load prescribed by ISO and ASTM standards for the clinical application of these devices. PMID:25577214

Melli, Virginia; Juszczyk, Mateusz; Sandrini, Enrico; Bolelli, Giovanni; Bonferroni, Benedetta; Lusvarghi, Luca; Cigada, Alberto; Manfredini, Tiziano; De Nardo, Luigi

2015-01-01

370

Diseño de un molde de inyección 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 diseñar un molde de inyección de probetas normalizadas, destinadas a ensayos mecánicos, utilizando un sistema novedoso de cavidades intercambiables y deslizantes. El diseño 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 diseñar moldes con postizos intercambiables que ofrecen facilidades para la obtención de probetas diversas, con la característica 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 rápido de cavidades de moldeo. Para ello se requiere de un gran esfuerzo manual e inversión de tiempo. Partiendo de esa experiencia y de las tendencias recientes en la industria a usar moldes con sistemas de cambio rápido, el presente trabajo plantea el diseño 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 diseñado dos postizos, uno para la inyección de probetas tipo halterio y otro para barras rectangulares, las cuales pueden usarse en múltiples ensayos mecánicos (tracción, flexión e impacto). Para modelar y validar el molde diseñado 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 máquina de inyección: vertical y horizontal. La evaluación comparativa de los pros y los contras de cada molde favoreció al sistema horizontal, debido a sus facilidades de manipulación y garantías 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

María V, Candal; María I, Hernández.

2011-03-01

371

A novel injection-molded capsular device for oral pulsatile delivery based on swellable/erodible polymers.  

Science.gov (United States)

The feasibility of injection molding was explored in the preparation of a novel capsular device for oral pulsatile/delayed delivery based on swellable/erodible polymers. For this purpose, a mold intended to be coupled with a bench-top injection-molding press was designed. This was expected to enable the preparation of matching capsule cap and body items within a single manufacturing cycle and the selection of differing shell thicknesses (300, 600, and 900 ?m). Hydroxypropylcellulose (Klucel(®) EF, LF, and GF) was employed as the release-controlling polymer in admixture with polyethylene glycol 1500 (10%, w/w) as the plasticizer. After preliminary trials aimed at the setup of operating conditions, Klucel(®) EF and LF capsule shells with satisfactory technological properties were manufactured. The performance of capsular devices filled with a tracer drug powder was studied by means of a modified USP31 disintegration apparatus. Typical in vitro delayed release patterns were thereby obtained, with lag time increasing as a function of the wall thickness. A good correlation was found between the latter parameter and t (10%), i.e., the time to 10% release, for both polymer grades employed. On the basis of the overall results, the investigated technique was proven suitable for the manufacturing of an innovative pulsatile release platform. PMID:21267684

Gazzaniga, Andrea; Cerea, Matteo; Cozzi, Alberto; Foppoli, Anastasia; Maroni, Alessandra; Zema, Lucia

2011-03-01

372

Moldagem por injeção de pós cerâmicos: remoção da parafina e do polipropileno utilizados como veículo orgânico / Ceramic injection molding: removal of pafafin and polypropylene used as organic binder  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A moldagem por injeção de pós cerâmicos tem se tornado um processo altamente atrativo por aliar a versatilidade e a produtividade da moldagem por injeção convencional às propriedades inerentes aos materiais cerâmicos. A remoção do ligante, usado como veículo orgânico nesse processo, é uma das etapas [...] críticas para a produção de peças cerâmicas sem defeitos. Neste trabalho avaliou-se a influência da geometria das peças injetadas na remoção do ligante, tanto por imersão em solvente como por decomposição térmica. Alumina em pó foi misturada fisicamente a um ligante composto por polipropileno [PP], parafina [PW] e ácido esteárico [AE]. As peças com diferentes geometrias foram mantidas imersas em hexano, secas sob vácuo e acompanhada a variação de massa devido à solubilização do PW e AE. A determinação da porosidade das peças, realizada por meio das isotermas de adsorção/desorção de nitrogênio, mostrou um aumento de porosidade de 0,5% volume para aproximadamente 20% volume após a imersão em solvente. A remoção térmica do PP remanescente produziu hidrocarbonetos alifáticos e compostos insaturados, determinados e quantificados por espectroscopia de infravermelho, que permearam a estrutura porosa da peça. A geometria das peças tem grande influência na remoção do ligante, podendo afetar não só a qualidade do produto final, mas também as etapas subseqüentes do processo. Abstract in english Powder injection molding [PIM] has become highly attractive as it combines the versatility and productivity of conventional injection molding processes with the intrinsic properties of metallic and ceramic materials. The removal of organic binder, used as vehicles during the process, is one of the m [...] ost critical stages in the production of ceramic devices in this process. In this work, the influence from the geometry of the injected part on the removal of the organic binder was evaluated for both solvent immersion and thermal degradation processes. Alumina powder was mixed with an organic binder, comprising polypropylene [PP], paraffin wax [PW] and stearic acid [SA], and injection molded in different geometries. Immersion of ceramic parts in hexane induced the solubilization of PW and SA, confirmed by weight variation. Parts porosity, determined through nitrogen adsorption isotherm, showed an increase from 0.5 v% before immersion to ca. 20 v% after immersion. PP burnout produced aliphatic hydrocarbons and unsaturated compounds that flow through a porous structure produced in early stages of this process. Parts geometry plays an important role in binder removal, affecting the quality of the sintered part as well as the remaining stages of the process.

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

2004-09-01

373

Moldagem por injeção de pós cerâmicos: remoção da parafina e do polipropileno utilizados como veículo orgânico Ceramic injection molding: removal of pafafin and polypropylene used as organic binder  

Directory of Open Access Journals (Sweden)

Full Text Available A moldagem por injeção de pós cerâmicos tem se tornado um processo altamente atrativo por aliar a versatilidade e a produtividade da moldagem por injeção convencional às propriedades inerentes aos materiais cerâmicos. A remoção do ligante, usado como veículo orgânico nesse processo, é uma das etapas críticas para a produção de peças cerâmicas sem defeitos. Neste trabalho avaliou-se a influência da geometria das peças injetadas na remoção do ligante, tanto por imersão em solvente como por decomposição térmica. Alumina em pó foi misturada fisicamente a um ligante composto por polipropileno [PP], parafina [PW] e ácido esteárico [AE]. As peças com diferentes geometrias foram mantidas imersas em hexano, secas sob vácuo e acompanhada a variação de massa devido à solubilização do PW e AE. A determinação da porosidade das peças, realizada por meio das isotermas de adsorção/desorção de nitrogênio, mostrou um aumento de porosidade de 0,5% volume para aproximadamente 20% volume após a imersão em solvente. A remoção térmica do PP remanescente produziu hidrocarbonetos alifáticos e compostos insaturados, determinados e quantificados por espectroscopia de infravermelho, que permearam a estrutura porosa da peça. A geometria das peças tem grande influência na remoção do ligante, podendo afetar não só a qualidade do produto final, mas também as etapas subseqüentes do processo.Powder injection molding [PIM] has become highly attractive as it combines the versatility and productivity of conventional injection molding processes with the intrinsic properties of metallic and ceramic materials. The removal of organic binder, used as vehicles during the process, is one of the most critical stages in the production of ceramic devices in this process. In this work, the influence from the geometry of the injected part on the removal of the organic binder was evaluated for both solvent immersion and thermal degradation processes. Alumina powder was mixed with an organic binder, comprising polypropylene [PP], paraffin wax [PW] and stearic acid [SA], and injection molded in different geometries. Immersion of ceramic parts in hexane induced the solubilization of PW and SA, confirmed by weight variation. Parts porosity, determined through nitrogen adsorption isotherm, showed an increase from 0.5 v% before immersion to ca. 20 v% after immersion. PP burnout produced aliphatic hydrocarbons and unsaturated compounds that flow through a porous structure produced in early stages of this process. Parts geometry plays an important role in binder removal, affecting the quality of the sintered part as well as the remaining stages of the process.

Ricardo V. B. Oliveira

2004-09-01

374

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

375

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.

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

2004-06-01

376

Effect of mold rotation on inclusion distribution in bearing steel during electroslag remelting process  

Directory of Open Access Journals (Sweden)

Full Text Available To remove the inclusions in the ingots by conventional electroslag remelting (ESR, the bearing steel was prepared using ESR process but with mold rotation in this study. Experimental results show a reduction in amount of large inclusions when the mold rotation rate is 6 r·min-1, and the inclusions are uniformly distributed in the ESR ingot. As comparison with the electroslag ingots of conventional ESR (stationary mold, the portion of the Al2O3 inclusions smaller than 1 ?m in size increase from 38% to 41.4%, whereas that of the SiO2 inclusions increases from 48% to 74% in the ingots when mold rotation is applied. This phenomenon is caused by the decrease in metal droplet size, resulting in large contact area between the slag pool and metal droplets in ESR process with mold rotation. Moreover, the metal droplets have relatively long movement routes, leading to long metal contact time between the slag pool and metal droplets when a relative motion between the consumable electrodes and mold is present. However, when the mold rotation rate is increased to 45 r·min-1, inclusion removing effect decreases. An excessive rotation rate causes wild motion in the slag pool, which drives the molten metal droplets to move violently, and as a result, the slag is entrapped into the metal pool, decreasing the ability of slag absorbing inclusions.

Chang Lizhong

2014-09-01

377

Effect of mold rotation on inclusion distribution in bearing steel during electroslag remelting process  

OpenAIRE

To remove the inclusions in the ingots by conventional electroslag remelting (ESR), the bearing steel was prepared using ESR process but with mold rotation in this study. Experimental results show a reduction in amount of large inclusions when the mold rotation rate is 6 r·min-1, and the inclusions are uniformly distributed in the ESR ingot. As comparison with the electroslag ingots of conventional ESR (stationary mold), the portion of the Al2O3 inclusions smaller than 1 ?m in size increase...

Chang Lizhong; Shi Xiaofang; Wang Runxi

2014-01-01

378

Desenvolvimento de liga sinterizada de níquel por moldagem de pós por injeção / Development of sintered nickel alloy by powder injection molding  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A moldagem de pós por injeção é um processo de fabricação de elevada produtividade que possibilita obter componentes de geometria complexa, estreita precisão dimensional e boas propriedades mecânicas. Neste processo, uma mistura de uma determinada quantidade de pós e ligantes orgânicos (polímeros, c [...] eras e óleos) é obtida por meio de uma massa de injeção (feedstock) o qual tem características reológicas adequadas para promover a injeção desta massa em uma cavidade de um molde. A produção de ligas de níquel por meio deste processo é uma alternativa para produção de produtos que requerem aplicações avançadas onde se exige resistência a corrosão e oxidação, resistência mecânica a altas temperaturas e baixo coeficiente de atrito. Neste trabalho apresentamos um estudo das propriedades microestruturais e mecânicas de uma liga de níquel (Ni-Fe-Cr-P) processada via moldagem de pós por injeção, utilizando pós de níquel carbonila com e sem a presença de fase líquida durante a sinterização. Os resultados foram comparados com a mesma liga processada por compactação de pós. Os resultados demonstraram a necessidade de maior quantidade de matéria orgânica para o desenvolvimento da massa de injeção (feedstock: 15% m/m de polímero) para os tipos de pós metálicos utilizados (níquel carbonila do tipo INCO 123) se comparado ao feedstock de ligas comerciais que normalmente utilizam uma quantidade menor de matéria orgânica (feedstock: 9% m/m de polímero). A maior quantidade de matéria orgânica necessária para a preparação do feedstock deve-se a morfologia dos pós empregados (superficie rugosa - tipo spiky) que promove retenção de carbono durante o processo de extração, ocasionando a necessidade de otimização do ciclo de extração térmica e sinterização. Ciclos mais lentos e a baixa temperatura promoveram a total retirada dos ligantes. A liga de Ni-Fe-Cr-P injetada apresentou contração de aproximadamente 50%, além de elevado teor de poros quando comparado ao material compactado, o que influenciou as propriedades mecânicas e dureza aparente do material. Abstract in english The powder injection molding is a manufacturing process that allows high productivity to obtain complex geometry components, dimensional accuracy and good mechanical properties. In this process, a mixture of a quantity of powders and organic binders (polymers, waxes, oils) is obtained through inject [...] ion of a mass (feedstock) which has rheological properties suitable for promoting the injection of this mass in a cavity of a mold. The production of nickel alloy by this process is an alternative to production of products that require advanced applications, which require resistance to corrosion and oxidation, mechanical strength at high temperatures and low coefficient of friction. This paper we present the study of the microstructural and mechanical properties of a nickel alloy (Ni-Fe-Cr-P) processed by powder injection molding, using carbonyl nickel powders with and without the presence of liquid phase during sintering. The results are compared with the alloy processed by powder compaction. The results demonstrate the need for increased amount of organic matter for developing the injection mass (feedstock: 15 wt.% polymer) for the types of metallic powders used (nickel INCO type 123 carbonyl) compared to commercial alloy feedstock typically use a smaller amount of organic matter (feedstock: 9 wt.% polymer). The largest quantity of organic matter needed for the preparation of the feedstock due to the morphology of the powders used (spiky) which promoted carbon retention during the extraction process, resulting in the need to optimize the extraction cycle and thermal sintering. Slower cycles and low temperature promoted the complete extraction of the ligands. The Ni-Fe-Cr-P alloy injected showed shrinkage of approximately 50%, and high levels of pores as compared to the compacted material, which influenced the m

Moisés Luiz, Parucker; Aloisio Nelmo, Klein; Roberto, Binder.

2014-09-01

379

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; Østergaard, Peter Friis

2012-01-01

380

Applying simulation to optimize plastic molded optical parts  

Science.gov (United States)

Optical injection molded parts are used in many different industries including electronics, consumer, medical and automotive due to their cost and performance advantages compared to alternative materials such as glass. The injection molding process, however, induces elastic (residual stress) and viscoelastic (flow orientation stress) deformation into the molded article which alters the material's refractive index to be anisotropic in different directions. Being able to predict and correct optical performance issues associated with birefringence early in the design phase is a huge competitive advantage. This paper reviews how to apply simulation analysis of the entire molding process to optimize manufacturability and part performance.

Jaworski, Matthew; Bakharev, Alexander; Costa, Franco; Friedl, Chris

2012-10-01

381

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

OpenAIRE

The main problems caused by improper gating are entrained aluminum oxide fi lms and entrapped gas. In this study, the slot gating system is employed to improve mold fi lling behavior and therefore, to improve the quality of aluminum castings produced in permanent molds. An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum fl owing into permanent molds have been developed. Graphite molds transparent to X-rays are utilized which make it possible to obs...

Chen Changjun; Chen Xia; Chang Qingming

2009-01-01

382

An investigation of flow properties of metal matrix composites suspensions for injection molding  

International Nuclear Information System (INIS)

Flow properties of metal matrix composites suspensions have significant effects on the fibre orientation during mould filling. The results presented in this paper relate to the flow properties of aluminium powder and glass fibres compounded into a sacrificial thermoplastics binder. For this purpose, a range of aluminium compounds and aluminium composite suspensions were investigated over a wide shear rate range expected to occur during injection mould process. Aluminium composites wee prepared by substituting glass fibres for aluminium in aluminium compound. Aluminium composite containing a maximum critical volume fraction of fibres which did not exhibit an increase n viscosity was determined. The effect of temperature on the flow behaviour of aluminium composite was also investigated. (author)

383

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

384

Silane based coating of aluminium mold  

DEFF Research Database (Denmark)

A method of preparing an aluminum mold for injection molding is provided, the method comprises the steps of providing an aluminum mold having a least one surface, subjecting the at least one surface to a gas or liquid phase silane to thereby form an anti-stiction coating, the anti-stiction coating comprising a chemically bonded monolayer of silane compounds on the at least one surface wherein the silane is a halogenated silane. The at least one surface coated with the anti-stiction coating may be configured to withstand an injection molding process at a pressure above 100 MPa. Furthermore, a mold having at least one closed cavity is provided, at least one surface of the at least one cavity being an aluminium surface coated with a silane based coating layer. The silane based anti-stiction coating improves the anti-stiction properties of the mold which may allow for molding and demolding of structures which would otherwise be difficult to mold. The resistance of the coated aluminium mold is significantly improved by applying a silane-based coating layer.

Cech, Jiri Technical University of Denmark,

385

Embedded fiber optic sensors for monitoring processing, quality and structural health of resin transfer molded components  

Energy Technology Data Exchange (ETDEWEB)

Due to their small size and flexibility fiber optics can be embedded into composite materials with little negative effect on strength and reliability of the host material. Fiber optic sensors such as Fiber Bragg Gratings (FBG) or Etched Fiber Sensors (EFS) can be used to detect a number of relevant parameters such as flow, degree of cure, quality and structural health throughout the life of a composite component. With a detection algorithm these embedded sensors can be used to detect damage in real time while the component remains in service. This paper presents the research being conducted on the use of fiber optic sensors for process and Structural Health Monitoring (SHM) of Resin Transfer Molded (RTM) composite structures. Fiber optic sensors are used at all life stages of an RTM composite panel. A laboratory scale RTM apparatus was developed with the capability of visually monitoring the resin filling process. A technique for embedding fiber optic sensors with this apparatus has also been developed. Both FBGs and EFSs have been embedded in composite panels using the apparatus. EFSs to monitor the fabrication process, specifically resin flow have been embedded and shown to be capable of detecting the presence of resin at various locations as it is injected into the mold. Simultaneously these sensors were multiplexed on the same fiber with FBGs, which have the ability to measure strain. Since multiple sensors can be multiplexed on a single fiber the number of ingress/egress locations required per sensor can be significantly reduced. To characterize the FBGs for strain detection tensile test specimens with embedded FBG sensors have been produced. These specimens have been instrumented with a resistive strain gauge for benchmarking. Both specimens and embedded sensors were characterized through tensile testing. Furthermore FBGs have been embedded into composite panels in a manner that is conducive to detection of Lamb waves generated with a centrally located PZT. To sense Lamb waves a high speed, high precision sensing technique is required to acquire data from embedded FBGs due to the high velocities and small strain amplitudes of these guided waves. A technique based on a filter consisting of a tunable FBG was developed. Since this filter is not dependant on moving parts, tests executed with this filter concluded with the detection of Lamb waves, removing the influence of temperature and operational strains. A damage detection algorithm was developed to detect and localize cracks and delaminations.

Keulen, C; Rocha, B; Suleman, A [University of Victoria, Department of Mechanical Engineering, PO Box 3055, Stn. CSC, Victoria, B.C., V8W 3P6 (Canada); Yildiz, M, E-mail: suleman@uvic.ca [Sabanci University, Faculty of Engineering and Natural Sciences, Orhanli - Tuzla, 34956, Istanbul (Turkey)

2011-07-19

386

Embedded fiber optic sensors for monitoring processing, quality and structural health of resin transfer molded components  

International Nuclear Information System (INIS)

Due to their small size and flexibility fiber optics can be embedded into composite materials with little negative effect on strength and reliability of the host material. Fiber optic sensors such as Fiber Bragg Gratings (FBG) or Etched Fiber Sensors (EFS) can be used to detect a number of relevant parameters such as flow, degree of cure, quality and structural health throughout the life of a composite component. With a detection algorithm these embedded sensors can be used to detect damage in real time while the component remains in service. This paper presents the research being conducted on the use of fiber optic sensors for process and Structural Health Monitoring (SHM) of Resin Transfer Molded (RTM) composite structures. Fiber optic sensors are used at all life stages of an RTM composite panel. A laboratory scale RTM apparatus was developed with the capability of visually monitoring the resin filling process. A technique for embedding fiber optic sensors with this apparatus has also been developed. Both FBGs and EFSs have been embedded in composite panels using the apparatus. EFSs to monitor the fabrication process, specifically resin flow have been embedded and shown to be capable of detecting the presence of resin at various locations as it is injected into the mold. Simultaneously these sensors were multiplexed on the same fiber with FBGs, which have the ability to measure strain. Since multiple sensors can be multiplexed on a single fiber the number of ingresxed on a single fiber the number of ingress/egress locations required per sensor can be significantly reduced. To characterize the FBGs for strain detection tensile test specimens with embedded FBG sensors have been produced. These specimens have been instrumented with a resistive strain gauge for benchmarking. Both specimens and embedded sensors were characterized through tensile testing. Furthermore FBGs have been embedded into composite panels in a manner that is conducive to detection of Lamb waves generated with a centrally located PZT. To sense Lamb waves a high speed, high precision sensing technique is required to acquire data from embedded FBGs due to the high velocities and small strain amplitudes of these guided waves. A technique based on a filter consisting of a tunable FBG was developed. Since this filter is not dependant on moving parts, tests executed with this filter concluded with the detection of Lamb waves, removing the influence of temperature and operational strains. A damage detection algorithm was developed to detect and localize cracks and delaminations.

387

Model and numerical simulation for the evolution of residual wall thickness in Water-Assisted Injection Molding  

Science.gov (United States)

The motion of water-melt interface confined in horizontal circular tubes during Water-Assisted Injection Molding (WAIM) has been studied both theoretically and experimentally. Of particular interest is the determination of residual melt film thickness on the walls. The reduced governing equations for viscous compressible non-Newtonian polymer melt during the second penetration in WAIM were established using dimensionless method. A formula used to calculate the second penetrating velocity was derived based on mathematical inference and mechanical principle. Experiments was conducted to measure the displacement of the water-melt interface as a function of the melt temperature, water pressure. The experimental results indicate the first penetration theory is not accurate in predicting residual wall thickness and the combined first and second penetration theories can improve the accuracy significantly.

Li, Qian; Cao, Wei; Zhang, Shixun; Shen, Changyu

2010-06-01

388

Effects of Wave Attenuation on the Acoustic Emission Amplitude Distribution of Injection-Molded Fiber/Plastic Composites  

International Nuclear Information System (INIS)

The attenuation of acoustic emission (AE) waves was evaluated for injection-molded short-fiber-reinforced thermoplastic composites employing simulated AE waves. Values of attenuation coefficient (?) decreased more with increasing fiber volume fraction (V1) than that expected from a simple linear relation between ? and V1. The effect of wave attenuation was taken into account in a quantitative analysis of the AE peak amplitude distribution which was obtained from each zone partitioned in a specimen gage portion. The amplitude distribution compensated for the measured attenuation loss was exhibited almost similar in every zone of the specimen. Consequently, it was, shown that the AE amplitudes obtained from fiber/plastic composites were considerably affected by the attenuation

389

FINITE ELEMENT MODELING SIMULATION IN THE STRAW PELLET COLD COMPRESSING MOLDING PROCESS  

Directory of Open Access Journals (Sweden)

Full Text Available According to the character of straw pellet fuel cold molding technology, the compressing process was modeled by Finite Element Modeling (FEM structure analysis tools. This indicated the variation laws between the stress and the strain, and the influence of the structure parameters of the die on the stress and the strain. It’s concluded from the work that when the length-to-diameter ratio of the die was 5.2 and the conicity of the die was 45o, the compress molding showed better degree of bonding and finish. This provided theoretical evidence for the study of the molding mechanism of the straw pellet and the selection of the structure parameters of the die.

Jianjun Hu

2010-11-01

390

Interface conditions of two-shot molded parts  

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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, E-mail: thomas.kisslinger@pccl.at [Polymer Competence Center Leoben GmbH, 8700 Leoben (Austria); Bruckmoser, Katharina, E-mail: katharina.bruckmoser@unileoben.ac.at; Resch, Katharina, E-mail: katharina.resch@unileoben.ac.at [Department of Polymer Engineering and Science, Chair of Materials Science and Testing of Polymers, Montanuniversitaet Leoben, 8700 Leoben (Austria); Lucyshyn, Thomas, E-mail: thomas.lucyshyn@unileoben.ac.at, E-mail: guenter.langecker@unileoben.ac.at; Langecker, Guenter Ruediger, E-mail: thomas.lucyshyn@unileoben.ac.at, E-mail: guenter.langecker@unileoben.ac.at; Holzer, Clemens, E-mail: clemens.holzer@unileoben.ac.at [Department of Polymer Engineering and Science, Chair of Polymer Processing, Montanuniversitaet Leoben, 8700 Leoben (Austria)

2014-05-15

391

Interface conditions of two-shot molded parts  

International Nuclear Information System (INIS)

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