WorldWideScience
 
 
1

CREEP MODELING FOR INJECTION-MOLDED LONG-FIBER THERMOPLASTICS  

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-06-30

2

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

International Nuclear Information System (INIS)

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

2009-09-15

3

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-10-30

4

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-09-01

5

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

6

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-01-01

7

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-01-01

8

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-01-26

9

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

10

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

11

An overview of long fiber reinforced thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

Long fiber reinforced thermoplastics (LFRTP) are a class of injection molding materials that extend the physical property envelope of thermoplastics polymers. These materials are manufactured by pulling continuous fiber tows through a thermoplastic polymer melt in a specialized processing die. The strands are subsequently cooled and chopped into pellets of equal length. LFRTP materials are available in virtually every common thermoplastic resin with glass, aramid, stainless steel, or carbon fiber reinforcement at levels up to 60% by weight. Unlike short fiber reinforced thermoplastics manufactured by conventional screw compounding processes, LFRTP exhibit simultaneous improvements in both flexural modulus and impact resistance. Improvements in load transfer, creep resistance at elevated temperatures, and dimensional stability can also be attributed to the long fiber network formed in the molded part. This unique combination of properties makes LFRTP the material of choice for replacement of metal structural assemblies in many automotive, industrial, consumer and recreational applications.

Bockstedt, R.J.; Skarlupka, R.J. [Polymer Composites Inc., Winona, MN (United States)

1995-12-01

12

An overview of long fiber reinforced thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

Long fiber reinforced thermoplastics (LFRTP) are a class of injection molding materials that extend the physical property envelope of thermoplastic polymers. The technology to manufacture LFRTP has improved during the last 10 years. This has resulted in dramatic improvements in the quality of these materials. They are now used in numerous, high volume commercial applications. LFRTP are pelletized, fiber reinforced thermoplastic polymers which are injection molded to form parts. The reinforcing fibers are 9-12 mm in length, compared to 0.5-1.0 mm typically found in other fiber reinforced thermoplastic materials. These longer fibers provide several property enhancements: higher impact strength, improved modulus at elevated temperatures and better dimensional stability. LFRTP are manufactured by pulling continuous fiber tows through a thermoplastic polymer melt in a specialized processing die. The ratio of fiber to resin is controlled by a metering orifice. The resulting rods are cut into pellets, 8-12 mm in length, that can be injection molded to form a part. Early manufacturing attempts mimicked wire-coating technology and did not wet-out the individual fibers within the tow. This resulted in poorly wet-out pellets, containing high levels of loose fibers. This creates problems in automated material handling and produces potential flaws in a molded part.

Bockstedt R.J.; Skarlupka, R.J. [Polymer Composites Inc., Winona, MN (United States)

1997-12-31

13

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-01-01

14

Modeling of Low Velocity Impact Damage in Injection-Molded Long Fiber Composites  

Energy Technology Data Exchange (ETDEWEB)

Apart from increase in failure strength, increase in the impact resistance is one of the major reasons for the interest in long-fiber polymer composites for automotive structural applications. The in-house code EMTA has been adapted to accommodate dynamic problems. It combines with ABAQUS Explicit solver to model impact behavior of long-fiber thermoplastics. At the present stage, the model captures the elastic behavior of LFTs in a dynamic formulation that incorporates the Eshelby equivalent inclusion method, the Mori-Tanaka assumption and the fiber orientation averaging technique. The effect of average fiber length on the impact behavior of discontinuous fiber composites has been studied with the aid of the preliminary model. Fiber lengths from short fiber range to long fiber range were explored with fiber orientation distributions from obtained from previous studies. The numerical examples indicate a slight improvement in the energy absorption capabilities of long fiber thermoplastics over short fiber thermoplastics. Advanced impact models need to be incorporated into the current code to model impact behavior with greater accuracy.

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

2009-09-15

15

Modeling Fatigue Damage in Long-Fiber Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper applies a fatigue damage model recently developed for injection-molded long-fiber thermoplastics (LFTs) to predict the modulus reduction and fatigue lifetime of glass/polyamide 6,6 (PA6,6) specimens. The fatigue model uses a multiscale mechanistic approach to describe fatigue damage accumulation in these materials subjected to cyclic loading. Micromechanical modeling using a modified Eshelby-Mori-Tanaka approach combined with averaging techniques for fiber length and orientation distributions is performed to establish the stiffness reduction relation for the composite as a function of the microcrack volume fraction. Next, continuum damage mechanics and a thermodynamic formulation are used to derive the constitutive relations and the damage evolution law. The fatigue damage model has been implemented in the ABAQUS finite element code and has been applied to analyze fatigue of the studied glass/PA6,6 specimens. The predictions agree well with the experimental results.

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

2009-10-30

16

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

17

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-07-01

18

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

19

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

Science.gov (United States)

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

Bloß, P.; Böhme, A.; Müller, J.; Krajewsky, P.; Michaelis, J.

2014-05-01

20

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

Science.gov (United States)

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

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

2014-05-01

 
 
 
 
21

An Elastic-Plastic Damage Model for Long-Fiber Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This article proposes an elastic-plastic damage model that combines micromechanical modeling with continuum damage mechanics to predict the stress-strain response of injection-molded long-fiber thermoplastics. The model accounts for distributions of orientation and length of elastic fibers embedded in a thermoplastic matrix whose behavior is elastic-plastic and damageable. The elastic-plastic damage behavior of the matrix is described by the modified Ramberg-Osgood relation and the three-dimensional damage model in deformation assuming isotropic hardening. Fiber/matrix debonding is accounted for using a parameter that governs the fiber/matrix interface compliance. A linear relationship between this parameter and the matrix damage variable is assumed. First, the elastic-plastic damage behavior of the reference aligned-fiber composite containing the same fiber volume fraction and length distribution as the actual composite is computed using an incremental Eshelby-Mori-Tanaka mean field approach. The incremental response of the latter is then obtained from the solution for the aligned-fiber composite by averaging over all fiber orientations. The model is validated against the experimental stress-strain results obtained for long-glass-fiber/polypropylene specimens.

Nguyen, Ba Nghiep; Kunc, Vlastimil

2009-08-11

22

Ceramic injection molding  

International Nuclear Information System (INIS)

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

1988-11-01

23

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

Science.gov (United States)

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

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

2014-05-01

24

Thermoplastic film infusion process for long fiber reinforced composites using rubber expandable tools  

Energy Technology Data Exchange (ETDEWEB)

Thermoplastic film infusion process was investigated by using a rubber tool, which intrinsically contains a thermally-expandable characteristic and effectively compensates for the pressure loss caused by thermoplastic polymer infusion. Increasing temperature up to the melting temperature of matrix, the polymer melt subsequently infused into the dry fabric, but the pressure was successfully sustained by the rubber tool. Even with the decreased resin volume, the rubber tool produced sufficiently high elastic force for continuous resin infusion. Combining D'Arcy's law with the compressibility of rubber tool and elastic fiber bed, a film infusion model was developed to predict the resin infusion rate and pressure change as a function of time. In addition, the film infusion process without the rubber tool was viewed and analyzed by a compression process of the elastic fiber bed and viscous resin melt. The compressibility of fiber bed was experimentally measure and the multiple-step resin infusion was well described by the developed model equations. (author). 36 refs., 9 figs.

Kim, D.W. [Oriental Industry Co, Ltd. (Korea); An, Y.S.; Lee, Y.K. [Sungkyunkwan University, Suwon (Korea); Kim, S.W. [Kyunggi University, Suwon (Korea); Nam, S.D. [Sungkyunkwan University, Suwon (Korea)

2001-01-01

25

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 â??Nanoplastâ? 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

26

Processing and evaluation of long fiber thermoplastic composite plates for internal fixation  

Science.gov (United States)

The metallic plates used in internal fracture fixation may have up to ten times the elastic modulus of normal bone tissue, causing stress shielding-induced osteopenia in healed bone that can lead to re-fracture after plate removal and prolonged and painful recovery. Thermoplastic polymer matrix composites reinforced with long carbon fiber are promising alternative materials for internal fixation plates because they may be produced with relative ease and be tailored to have specific mechanical properties, alleviating the stress shielding problem. Long carbon fiber-reinforced polyetheretherketone (LCF PEEK) plates were produced using the extrusion / compression molding process. Static flexural testing determined that LCF PEEK plates with rectangular cross-section had an average flexural modulus of 12 GPa, or 23% of the flexural modulus of a stainless steel plate. The LCF PEEK plates also experienced negligible (14.7%, 14.5%, and 16.7%) reductions in modulus after fatigue testing at applied moments of 2.5, 3.0, and 3.5 N•m, respectively, over 106 load cycles. Aging the plates in 0.9% NaCl solution for four and eight weeks caused 0.34% and 0.28% increases in plate mass, respectively. No significant decrease of flexural properties due to aging was detected. Differential scanning calorimetry (DSC) revealed the PEEK matrix of the plates to be 24.5% crystalline, which is lower than typical PEEK crystallinity values of 30-35%. Scanning electron microscopy (SEM) revealed three times as many fiber pullout areas in LCF PEEK fracture surfaces as in fracture surfaces of long carbon fiber-reinforced polyphenylenesulfide (LCF PPS), another plate material tested. DSC and SEM data suggest that improvements in processing conditions and fiber/matrix bonding, along with higher carbon fiber fractions, would enhance LCF PEEK plate performance. LCF PEEK remains a promising alternative to stainless steel for internal fixation plates.

Warren, Paul B.

27

Progress in Titanium Metal Powder Injection Molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Metal powder injection molding is a shaping technology that has achieved solid scientific underpinnings. It is from this science base that recent progress has occurred in titanium powder injection molding. Much of the progress awaited development of the required particles with specific characteristics of particle size, particle shape, and purity. The production of titanium components by injection molding is stabilized by a good understanding of how each process variable impacts density and im...

German, Randall M.

2013-01-01

28

CD injection molding I: Navier-Stokes  

Science.gov (United States)

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

Powell, Adam C., IV

2004-08-26

29

On Optimization of Injection Molding Cooling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Ra?nnar, Lars-erik

2008-01-01

30

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

International Nuclear Information System (INIS)

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

2007-01-01

31

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

Science.gov (United States)

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

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

2014-05-01

32

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

33

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

34

Surface microstructure replication in injection molding  

DEFF Research Database (Denmark)

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

Hansen, Hans Nørgaard

2006-01-01

35

Nanostructuring steel for injection molding tools  

DEFF Research Database (Denmark)

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

Kristensen, Anders

2014-01-01

36

The manufactoring of a two–layered injection mold by welding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2011-01-01

37

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2007-01-01

38

Binder Removal from Powder Injection Molded 316L Stainless Steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study reports the results of preparation of 316L stainless steel polymer based injection molded feed stock, rheology of feed stock and injection molding. The plastic binder was extracted from molded samples. The binder extraction was carried out in two steps: by solvent and thermal techniques. The results showed that feed stock prepared was suitable for injection molding and this was confirmed by rheology data measured by using capillary rheometer. The test samples were injection molded ...

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

2011-01-01

39

Structural development of HDPE in injection molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2003-01-01

40

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

 
 
 
 
41

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

42

Functional nanostructures on injection molded plastic  

DEFF Research Database (Denmark)

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

Johansson, Alicia Charlotte; Søgaard, Emil

43

Simulation and Design of a plastic injection mold  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Teklehaimanot, Samson Seged

2012-01-01

44

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

45

Preparation and Characterization of Copper Feedstock for Metal Injection Molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Powder loading is one of the most critical factors which have important influence on metal injection molding processes. In this study, four different loading feedstocks were prepared from gas atomized copper powder with wax-based binders. Mixes of four feedstocks with 2 Vol. % incremental powders loading from 55% to 61 Vol. % were carried out in a Z-blade mixer. The injection molding was carried out at low pressure. A combination of solvent and thermal debinding was used for binder removal fr...

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

2010-01-01

46

FPGA-Based Multiprocessor System for Injection Molding Control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA) device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic...

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

2012-01-01

47

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

48

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

49

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

Science.gov (United States)

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

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

2013-01-01

50

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

Science.gov (United States)

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

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

2004-06-01

51

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

Energy Technology Data Exchange (ETDEWEB)

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

Nishiwaki, Nobuhiko; Hori, Sankei

1999-07-01

52

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

53

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-05-01

54

CENTRAL CONVEYING & AUTO FEEDING SYSTEMS FOR AN INJECTION MOLDING SHOP  

Directory of Open Access Journals (Sweden)

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

Sanjeev Kumar

2011-08-01

55

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

56

Vacuum-injection molding of glass-metal electrical components  

Energy Technology Data Exchange (ETDEWEB)

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

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

1983-01-01

57

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

58

Residual stress distribution in injection molded parts  

Directory of Open Access Journals (Sweden)

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

P. Postawa

2006-08-01

59

Metal Injection Molding of Alloy 718 for Aerospace Applications  

Science.gov (United States)

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

Ott, Eric A.; Peretti, Michael W.

2012-02-01

60

Microstructural and mechanical characterization of injection molded 718 superalloy powders  

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-11-05

 
 
 
 
61

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

Energy Technology Data Exchange (ETDEWEB)

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

Grendol, C.L.

1987-05-01

62

Process and part filling control in micro injection molding  

DEFF Research Database (Denmark)

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

Tosello, Guido; Hansen, Hans Nørgaard

2008-01-01

63

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

64

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

65

Microcellular injection-molding of polylactide with chain-extender  

International Nuclear Information System (INIS)

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

2009-05-05

66

FPGA-Based Multiprocessor System for Injection Molding Control  

Science.gov (United States)

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

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

2012-01-01

67

FPGA-Based Multiprocessor System for Injection Molding Control  

Directory of Open Access Journals (Sweden)

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

Roque A. Osornio-Rios

2012-10-01

68

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

69

CAE for Injection Molding - Past, Present and the Future  

Science.gov (United States)

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

Wang, Kuo K.

2004-06-01

70

Micro injection molding: characterisation of cavity filling process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

71

Injection-molded nanocomposites and materials based on wheat gluten  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2011-01-01

72

Two component micro injection molding for MID fabrication  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2008-01-01

73

TWO COMPONENT MICRO INJECTION MOLDING FOR MID FABRICATION  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2008-01-01

74

A Novel Method of Injection Molding Titanium Components  

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-05-01

75

Injection molding of high aspect ratio sub-100 nm nanostructures  

Science.gov (United States)

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

Matschuk, Maria; Larsen, Niels B.

2013-02-01

76

Evaluation of novel tooling for nanoscale injection molding  

Science.gov (United States)

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

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

2005-05-01

77

Experiments and Simulation of Injection Molding with Microstructures  

Science.gov (United States)

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

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

2004-06-01

78

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

79

Bubble growth in mold cavities during microcellular injection molding processes  

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-12-15

80

Bubble growth in mold cavities during microcellular injection molding processes  

International Nuclear Information System (INIS)

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

2009-12-01

 
 
 
 
81

Residual orientation in micro-injection molded parts  

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-06-30

82

Residual orientation in micro-injection molded parts  

International Nuclear Information System (INIS)

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

2007-04-01

83

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,

84

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Composites of high density polyethylene (HDPE) with hydroxyapatite (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

85

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

86

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1994-09-30

87

A Recurrent Neural Network for Warpage Prediction in Injection Molding  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish La 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.

88

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-07-01

89

Stability of FDTS monolayer coating on aluminum injection molding tools  

Science.gov (United States)

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

Cech, Jiri; Taboryski, Rafael

2012-10-01

90

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

91

Fatigue failure properties of injection molded superalloy compacts  

International Nuclear Information System (INIS)

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

2011-11-01

92

Viscosity and powder dispersion in ceramic injection molding mixtures  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-02-01

93

Semi-automatic laboratory equipment for reactive injection molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

94

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

95

Net shaping of tungsten components by micro powder injection molding  

International Nuclear Information System (INIS)

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

2006-09-11

96

Three dimensional modeling of metal powder injection molding  

International Nuclear Information System (INIS)

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

2000-08-20

97

Three dimensional modeling of metal powder injection molding  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-07-01

98

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

99

Processing development of Si3N4 components by injection molding  

International Nuclear Information System (INIS)

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

1997-06-04

100

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

 
 
 
 
101

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

Energy Technology Data Exchange (ETDEWEB)

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

Dropmann, M.

1993-05-01

102

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

103

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

104

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work reports on the relationships between processing, the morphology and the mechanical properties of an injection molded poly(ethylene terephthalate), PET. Specimens were injection molded with different mold temperatures of 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

105

Development of Defects Free Stainless Steel Parts Using Powder Injection Molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Austenitic 316L Stainless Steel (SS) is widely used in aerospace, automotive, sports and medical industries due to its mechanical properties and corrosion resistance. Defects free molding of parts depends upon the features of feedstock. In powder injection molding, feedstock preparation is critical step and any deficiency at this stage cannot be retrieve in latter steps. The objective of this research work is to optimize solid loading for defects free injection molded parts. During the ...

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

2013-01-01

106

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Patcharaphun, Somjate

2006-01-01

107

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

1997-01-01

108

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites  

Energy Technology Data Exchange (ETDEWEB)

This quarterly report summarizes the status for the project planning to complete all the legal and contract documents required for establishing the subcontracts needed and a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). During the second quarter (1/1/2013 to 3/31/2013), all the technical and legal documents for the subcontracts to Purdue University, University of Illinois, and PlastiComp, Inc. were completed. The revised CRADA documents were sent to DOE, Autodesk, Toyota, and Magna for technical and legal reviews. PNNL Legal Services contacted project partners’ Legal counterparts for completing legal documents for the project. A non-disclosure agreement was revised and sent to all the parties for reviews.

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-05-30

109

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

Energy Technology Data Exchange (ETDEWEB)

This quarterly report summarizes the status for the project planning to initiate all the legal and contract documents required for establishing the subcontracts needed and a Cooperative Research and Development Agreement (CRADA) with Autodesk, Inc., Toyota Motor Engineering and Manufacturing North America (Toyota), and Magna Exterior and Interiors Corporation (Magna). During the first quarter (10/1/2012 to 12/31/2012), the statements of work (SOW) for the subcontracts to Purdue University, University of Illinois, and PlastiComp, Inc. were completed. A draft of the CRADA SOW was sent to Autodesk, Toyota, and Magna for technical and legal reviews. PNNL Legal Services contacted project partners’ Legal counterparts for preparing legal documents for the project. A non-disclosure agreement was drafted and sent to all the parties for reviews.

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-04-04

110

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

111

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

112

Implementation and analysis of polymeric microstructure replication by micro injection molding  

Science.gov (United States)

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

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

2004-03-01

113

Fiber Reinforcement in Injection Molded Nylon 6/6 Spur Gears  

Science.gov (United States)

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

Senthilvelan, S.; Gnanamoorthy, R.

2006-07-01

114

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

DEFF Research Database (Denmark)

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

Jensen, Marie Pødenphant; Marie, Rodolphe

2014-01-01

115

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-06-25

116

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

117

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

118

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

Directory of Open Access Journals (Sweden)

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

Kwangho Shin

2013-12-01

119

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

Science.gov (United States)

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

Schütte, Julia; Freudigmann, Christian; Benz, Karin; Böttger, Jan; Gebhardt, Rolf; Stelzle, Martin

2010-10-01

120

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

 
 
 
 
121

Investigation of foaming behaviors in injection molding using mold pressure profile  

Science.gov (United States)

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

Lee, John W. S.

122

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

Science.gov (United States)

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

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

2006-03-01

123

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

Energy Technology Data Exchange (ETDEWEB)

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

Allen, G.M.

1991-10-01

124

Multi-scale filling simulation of micro-injection molding process  

International Nuclear Information System (INIS)

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

2011-01-01

125

A Simulation Study of Conformal Cooling Channels in Plastic Injection Molding  

Directory of Open Access Journals (Sweden)

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

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

2013-09-01

126

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2001-01-01

127

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

128

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

2010-01-01

129

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The effect of injection molding parameters (screw rotational speed, back pressure, injec-tion flow rate and holding pressure) on the nanofiller dispersion of melt-mixed PP/clay nanocomposites was investigated. The nanocomposites containing 4 wt% clay were obtained by dilution of a PP/clay masterbatch into a PP matrix. The evaluation of the dispersion degree was obtained from dynamic rheological measurements. The storage modulus and complex viscosity exhibit significant dependence on the injec...

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

2012-01-01

130

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Hostert, Claude

2006-01-01

131

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2000-01-01

132

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

133

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

134

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

135

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2009-01-01

136

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-10-01

137

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

138

Determination of adhesion between thermoplastic and liquid silicone rubbers in hard-soft-combinations via mechanical peeling test  

Science.gov (United States)

The production of hard-soft-combinations via multi injection molding gained more and more importance in the last years. This is attributed to different factors. One principle reason is that the use of two-component injection molding technique has many advantages such as cancelling subsequent and complex steps and shortening the process chain. Furthermore this technique allows the combination of the properties of the single components like the high stiffness of the hard component and the elastic properties of the soft component. Because of the incompatibility of some polymers the adhesion on the interface has to be determined. Thereby adhesion is not only influenced by the applied polymers, but also by the injection molding parameters and the characteristics of the mold. Besides already known combinations of thermoplastics with thermoplastic elastomers (TPE), there consists the possibility to apply liquid silicone rubber (LSR) as soft component. A thermoplastic/LSR combination gains in importance due to the specific advantages of LSR to TPE. The faintly adhesion between LSR and thermoplastics is currently one of the key challenges when dealing with those combinations. So it is coercively necessary to improve adhesion between the two components by adding an adhesion promoter. To determine the promoters influence, it is necessary to develop a suitable testing method to investigate e.g. the peel resistance. The current German standard "VDI Richtlinie 2019', which is actually only employed for thermoplastic/TPE combinations, can serve as a model to determine the adhesion of thermoplastic/LSR combinations.

Kühr, C.; Spörrer, A.; Altstädt, V.

2014-05-01

139

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

Scientific Electronic Library Online (English)

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

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

140

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

 
 
 
 
141

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

142

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

Science.gov (United States)

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

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

2007-01-01

143

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

144

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

Directory of Open Access Journals (Sweden)

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

J. Soulestin

2012-03-01

145

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-04-01

146

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

Science.gov (United States)

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

Zook, Christopher David

147

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

148

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

149

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

Directory of Open Access Journals (Sweden)

Full Text Available In order to acquire the best filling time, Mold trial is made by setting different injection time, or Mold flow software is used to analyze data recorded by computer. Whether doing successive trials or being simulated point by point, is very tedious. A new method is put forward-seeking the minimum of curve being simulated by Lagrange interpolation. The minimum of the curve is the best filling time. This method can improve the efficiency of the simulation analysis. The software Mold flow provides the possibility to simulate the flow processes of plastic air intake manifold with different gate location and number of injection mold and to predict the position of air traps and weld lines. The location and number of the gate in injection mold are determined by comparing analysis results and avoid mold adjustment and mold repairing. Finished injection mold of plastic air intake manifold on basis of simulation is perfect.

Shiqiang Zhang

2013-01-01

150

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-07-01

151

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-12-01

152

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

Energy Technology Data Exchange (ETDEWEB)

The CRADA between PNNL, Autodesk, Toyota and Magna has been effective since October 28th, 2013. The whole team including CRADA and subcontract partners kicked off the project technically on November 1st, 2013. This report describes work performed during the first quarter of FY 2014. The following technical progresses have been made toward project milestones: 1) The project kickoff meeting was organized at PlastiComp, Inc. in Winona on November 13th, 2013 involving all the project partners. During this meeting the research plan and Gantt chart were discussed and refined. The coordination of the research activities among the partners was also discussed to ensure that the deliverables and timeline will be met. 2) Autodesk delivered a research version of ASMI to PNNL for process modeling using this tool under the project. PNNL installed this research version on a PNNL computer and tested it. Currently, PNNL is using ASMI to prepare the models for PlastiComp plaques. 3) PlastiComp has compounded long carbon-fiber reinforced polypropylene and polyamide 6,6 compounds for rheological and thermal characterization tests by the Autodesk laboratories in Melbourne, Australia. 4) Initial mold flow analysis was carried out by PlastiComp to confirm that the 3D complex part selected by Toyota as a representative automotive part is moldable. 5) Toyota, Magna, PlastiComp and PNNL finalized the planning for molding the Toyota 3D complex part. 6) Purdue University worked with PNNL to update and specify the test matrix for characterization of fiber length/orientation. 7) Purdue University developed tools to automate the data collection and analysis of fiber length and orientation measurements. 8) Purdue University designed and specified equipment to replace the need for equipment using the technology established by the University of Leeds at General Motors.

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

2014-02-19

153

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

Energy Technology Data Exchange (ETDEWEB)

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

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-12-02

154

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

Energy Technology Data Exchange (ETDEWEB)

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

Nguyen, Ba Nghiep; Simmons, Kevin L.

2013-08-06

155

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

156

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

Science.gov (United States)

The biodegradability of three types of bioplastic pots was evaluated by measuring carbon dioxide produced from lab-scale compost reactors containing mixtures of pot fragments and compost inoculum held at 58 °C for 60 days. Biodegradability of pot type A (composed of 100% polylactic acid (PLA)) was very low (13 ± 3%) compared to literature values for other PLA materials. Near infrared spectroscopy (NIRS) results suggest that the PLA undergoes chemical structural changes during polymer extrusion and injection molding. These changes may be the basis of the low biodegradability value. Biodegradability of pot types B (containing 5% poultry feather, 80% PLA, 15% starch), and C (containing 50% poultry feather, 25% urea, 25% glycerol), were 53 ± 2% and 39 ± 3%, respectively. More than 85% of the total biodegradation of these bioplastics occurred within 38 days. NIRS results revealed that poultry feather was not degraded during composting. PMID:21320772

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

2011-04-01

157

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

DEFF Research Database (Denmark)

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

Gava, Alberto; Tosello, Guido

2009-01-01

158

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

159

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

160

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

International Nuclear Information System (INIS)

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

2008-07-01

 
 
 
 
161

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

162

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

163

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

Science.gov (United States)

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

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

2009-11-01

164

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

International Nuclear Information System (INIS)

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

2009-10-13

165

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.

Ã?stergaard, Peter Friis; Matteucci, Marco

2012-01-01

166

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

International Nuclear Information System (INIS)

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

2010-01-01

167

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

168

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

169

CONVERSION OF WIND POWER TO HYDROGEN FUEL: DESIGN OF AN ALTERNATIVE ENERGY SYSTEM FOR AN INJECTION MOLDING FACILITY  

Science.gov (United States)

Injection molding plants are large consumers of electricity. At its current level of operations, Harbec Plastics (Ontario, NY) uses about 2,000,000 kilowatt-hours of electricity per year. Based on the US average fuel mix, approximately 1.5 pounds of CO2...

170

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

171

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-04-20

172

Micromechanical modeling of the progressive failure in short glass-fiber reinforced thermoplastics  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermoplastics reinforced with short glass fibers are increasingly used in many industrial applications due to their attractive mechanical properties, rapid processing and relatively low manufacturing cost. Injection molding is a widely used process for the production of reinforced parts with complex shapes. However, the concentration and the orientation of the fibers vary from one point to the other. This induces a strong heterogeneity throughout the material, making the prediction of its be...

Kammoun, Slim

2011-01-01

173

Casein and soybean protein-based thermoplastics and composites as alternative biodegradable polymers for biomedical applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work reports on the development and characterization of novel meltable polymers and composites based on casein and soybean proteins. The effects of inert (Al(2)O(3)) and bioactive (tricalcium phosphate) ceramic reinforcements over the mechanical performance, water absorption, and ioactivity behavior of the injection-molded thermoplastics were examined. It was possible to obtain materials and composites with a range of mechanical properties, which might allow for their application in the ...

Vaz, C. M.; Fossen, M.; Tuil, R. F.; Graaf, L. A.; Cunha, A. M.; Reis, R. L.

2003-01-01

174

Casein and soybean protein-based thermoplastics and composites as alternative biodegradable polymers for biomedical applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work reports on the development and characterization of novel meltable polymers and composites based on casein and soybean proteins. The effects of inert (Al2O3) and bioactive (tricalcium phosphate) ceramic reinforcements over the mechanical performance, water absorption, and bioactivity behavior of the injection-molded thermoplastics were examined. It was possible to obtain materials and composites with a range of mechanical properties, which might allow for their application in the bio...

Vaz, C. M.; Fossen, M.; Tuil, R. F.; Graaf, L. A.; Reis, R. L.; Cunha, A. M.

2003-01-01

175

Thermoforming of thermoplastic matrix composites. Part I  

Energy Technology Data Exchange (ETDEWEB)

Long-fiber-reinforced polymer matrix composites find widespread use in a variety of commercial applications requiring properties that cannot be provided by unreinforced plastics or other common materials of construction. However, thermosetting matrix resins have long been plagued by production processes that are slow and difficult to automate. This has limited the use of long-fiber-reinforced composites to relatively low productivity applications in which higher production costs can be justified. Unreinforced thermoplastics, by their very nature, can easily be made into sheet form and processed into a variety of formed shapes by various pressure assisted thermoforming means. It is possible to incorporate various types of fiber reinforcement to suit the end use of the thermoformed shape. Recently developed thermoplastic resins can also sometimes correct physical property deficiencies in a thermoset matrix composite. Many forms of thermoplastic composite material now exist that meet all the requirements of present day automotive and aerospace parts. Some of these are presently in production, while others are still in the development stage. This opens the possibility that long-fiber-reinforced thermoplastics might break the barrier that has long limited the applications for fiber-reinforced composites. 37 refs., 8 figs., 5 tabs.

Harper, R.C.

1992-03-01

176

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

Energy Technology Data Exchange (ETDEWEB)

Research highlights: > PP/CNFs and PP/TiO{sub 2} composites with relative high loading fractions (10, 20, 30 and 35 wt%) were fabricated by inner melt mixing process. Micro tensile test samples were formed by injection molding combined with variotherm process for all composites. > The morphological properties of all nano composites were characterized by WXRD, whose results imply the adding nano fillers did not change the crystal form of PP, but the crystallites size and distance between lattices of crystals were changed with various nano fillers and loading fractions. > DSC analysis show that due to the nucleating function of nano fillers, the peak temperature of crystallization was increased and the peak temperature of crystallization melting was decreased by adding the nanofillers. > The flow ability of nano composites was tested by high pressure single capillary rheometer and the results demonstrate that nano fillers increased the viscosity of PP matrix. > Based on these significant information and analysis foundation of the nano filled composites, the micro weld line samples were formed by injection molding process and characterized by tensile test method. From the achieved results, it can be found that in general, for functional nano filled polymer composites, the mechanical property of micro weld lines were obviously influenced by nano fillers' shape and loading fractions. > The E modulus of micro weld line was increased due to loading CNFs in PP matrix, while the elongation of the micro tensile samples with weld line is considerably decreased comparing with those of unfilled PP samples. The detrimental tensile strength of micro weld lines were observed when CNFs contents increasing, except for at a 10 wt%. > For TiO{sub 2} nano particles filled PP, due to the poor dispersion of nano particles, at low loading fraction of 10 wt%, the E modulus and tensile strength of micro weld lines were decreased by filling nano particles, but when the loading fraction is increased to 30%, the E modulus and tensile strength of micro weld line were increased again compared with the low loading level. > Finally, an empirical prediction equation for micro injection molded weld line strength of nano PP composites was proposed for higher nano filler loading fraction than 10 wt%. - Abstract: The nano filled functional polymer materials have been widely processed with micro injection molding technology for micro electromechanical systems (MEMS) fabrication. As the unfavorable defect in micro injection molding parts, weld line brings reduced mechanical and physical properties, especially for nano filled composites. In this study, polypropylene (PP) was compounded respectively with carbon nano fibers (CNFs) and TiO{sub 2} nano particles at various weight fractions (10, 20, 30, 35 wt%) through co-screws internal mixing. The morphological, thermal and rheological properties of nano composites were characterized by wider angle X-ray diffraction (WXRD), different scanning calorimeter (DSC) and high pressure capillary rheometer. Additionally, under the constant setting of injection molding process parameters in injection molding machine, micro tensile samples with weld lines for each nano filled PP composite were produced. The tensile tests were served as the characterizing method for weld line mechanical properties. The results show that when the CNFs is filled higher than 10 wt%, the tensile strength of samples with weld lines made of nano composites become lower than neat PP. While the raising CNFs content contributes to the improved E modulus of micro injection molded weld lines. Additionally, with the increasing fraction of CNFs in PP, the weld line area's elongation percent is decreased. Whereas for case of TiO{sub 2}, the 10 wt% is the threshold for micro injection molded weld line tensile strength turning from decrease trend to increase. The same as CNFs, elongation of micro weld line samples were in general lower than neat PP as well, due to the addition of TiO{sub 2} nano particles.

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

2011-01-12

177

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

International Nuclear Information System (INIS)

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

2011-01-12

178

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

Directory of Open Access Journals (Sweden)

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

Duarte Marcia Adriana Tomaz

2006-01-01

179

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.

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

180

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

Science.gov (United States)

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

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

 
 
 
 
181

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

182

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

Science.gov (United States)

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

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

2014-02-28

183

Model and simulation for melt flow in micro-injection molding based on the PTT model  

International Nuclear Information System (INIS)

Unsteady viscoelastic flows were studied using the finite element method in this work. The Phan-Thien–Tanner (PTT) model was used to represent the rheological behavior of viscoelastic fluids. To effectively describe the microscale effects, the slip boundary condition and surface tension were added to the mathematical model for melt flow in micro-injection molding. The new variational equation of pressure, including the viscoelastic parameters and slip boundary condition, was generalized using integration by parts. A computer code based on the finite element method and finite difference method was developed to solve the melt flow problem. Numerical simulation revealed that the melt viscoelasticity plays an important role in the prediction of melt pressure, temperature at the gate and the succeeding melt front advancement in the cavity. Using the viscoelastic model one can also control the rapid increase in simulated pressure, temperature, and reduce the filling difference among different cavities. The short shot experiments of micro-motor shaft showed that the predicted melt front from the viscoelastic model is in fair agreement with the corresponding experimental results

2011-12-01

184

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-09-15

185

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

186

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

187

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

Directory of Open Access Journals (Sweden)

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

Shinichi Shibata

2010-08-01

188

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

189

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

190

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

Science.gov (United States)

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

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

2014-05-01

191

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

192

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

International Nuclear Information System (INIS)

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

1987-01-01

193

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

194

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-03-15

195

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

Directory of Open Access Journals (Sweden)

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

M.S. Ramli

2011-01-01

196

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Dray, Delphine; Gilormini, Pierre; Regnier, Gilles

2007-01-01

197

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2012-01-01

198

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2011-01-01

199

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

200

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2004-01-01

 
 
 
 
201

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1994-03-13

202

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

203

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

204

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

205

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

International Nuclear Information System (INIS)

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

2011-10-01

206

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

207

Mechanical, dynamic-mechanical and thermal properties of soy protein-based thermoplastics with potential biomedical applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study the tensile and the dynamic-mechanical behavior of injection-molded samples of various soy protein thermoplastic compounds were evaluated as a function of the amount of glycerol, type and amount of ceramic reinforcement, and eventual incorporation of coupling agents. The incorporation of glycerol into a soy-based matrix resulted in its plasticization, as confirmed by the drop in stiffness (storage and elastic modulus) above 20degreesC and a decrease in the protein glass transiti...

Vaz, C. A.; Mano, J. F.; Fossen, M.; Tuil, R. F.; Graaf, L. A.; Reis, R. L.; Cunha, A. A.

2002-01-01

208

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

209

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

Energy Technology Data Exchange (ETDEWEB)

In this study, poly({epsilon}-caprolactone) (PCL)/sodium chloride (NaCl), PCL/poly(ethylene oxide) (PEO)/NaCl and PCL/PEO/NaCl/hydroxyapatite (HA) composites were injection molded and characterized. The water soluble and sacrificial polymer, PEO, and NaCl particulates in the composites were leached by deionized water to produce porous and interconnected microstructures. The effect of leaching time on porosity, and residual contents of NaCl and NaCl/HA, as well as the effect of HA addition on mechanical properties was investigated. In addition, the biocompatibility was observed via seeding human mesenchymal stem cells (hMSCs) on PCL and PCL/HA scaffolds. The results showed that the leaching time depends on the spatial distribution of sacrificial PEO phase and NaCl particulates. The addition of HA has significantly improved the elastic (E Prime ) and loss moduli (E Double-Prime ) of PCL/HA scaffolds. Human MSCs were observed to have attached and proliferated on both PCL and PCL/HA scaffolds. Taken together, the molded PCL and PCL/HA scaffolds could be good candidates as tissue engineering scaffolds. Additionally, injection molding would be a potential and high throughput technology to fabricate tissue scaffolds. - Highlights: Black-Right-Pointing-Pointer PCL/NaCl, PCL/PEO/NaCl and PCL/PEO/NaCl/HA composites were injection molded. Black-Right-Pointing-Pointer Leaching time depends on the distribution of PEO phase and NaCl particulates. Black-Right-Pointing-Pointer The elastic and loss moduli of PCL/HA scaffolds have significantly improved. Black-Right-Pointing-Pointer Human hMSCs have attached, survived and proliferated well on PCL and PCL/HA scaffolds. Black-Right-Pointing-Pointer Molded PCL and PCL/HA scaffolds could be good candidates for tissue engineering.

Cui Zhixiang [Zhengzhou University, Henan (China); Nelson, Brenton; Peng, YiYan [University of Wisconsin-Madison, Wisconsin (United States); Li Ke [South China University of Technology, Guangzhou (China); Pilla, Srikanth; Li Wanju [University of Wisconsin-Madison, Wisconsin (United States); Turng, Lih-Sheng, E-mail: turng@engr.wisc.edu [University of Wisconsin-Madison, Wisconsin (United States); South China University of Technology, Guangzhou (China); Huazhong University of Science of Technology, Wuhan (China); Shen Changyu, E-mail: shency@zzu.edu.cn [Zhengzhou University, Henan (China)

2012-08-01

210

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

211

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

Science.gov (United States)

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

Becker, Holger; Mühlberger, Holger; Hoffmann, Werner; Clemens, Thomas; Klemm, Richard; Gärtner, Claudia

2008-03-01

212

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

Science.gov (United States)

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

Höll, S; Haupt, M; Fischer, U H P

2013-06-20

213

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

Science.gov (United States)

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

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

2012-06-01

214

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

Science.gov (United States)

In injection molding processes, computer aided engineering (CAE) allows processors to evaluate different process parameters in order to achieve complete filling of a cavity and, in some cases, it predicts shrinkage and warpage. However, because commercial computational packages are used to design complex geometries, detail in the thickness direction is limited. Approximations in the thickness direction lead to the solution of a 2½-D problem instead of a 3-D problem. These simplifications drastically reduce computational times and memory requirements. However, these approximations hinder the ability to predict thermal and/or mechanical degradation. The goal of this study was to determine the degree of degradation during PVC injection molding and to compare the results with a computational model. Instead of analyzing degradation in complex geometries, the computational analysis and injection molding trials were performed on typical sections found in complex geometries, such as flow in a tube, flow in a rectangular channel, and radial flow. This simplification reduces the flow problem to a 1-D problem and allows one to develop a computational model with a higher level of detail in the thickness direction, essential for the determination of degradation. Two different geometries were examined in this study: a spiral mold, in order to approximate the rectangular channel, and a center gated plate for the radial flow. Injection speed, melt temperature, and shot size were varied. Parts varying in degree of degradation, from no to severe degradation, were produced to determine possible transition points. Furthermore, two different PVC materials were used, low and high viscosity, M3800 and M4200, respectively (The Geon Company, Avon Lake, OH), to correlate the degree of degradation with the viscous heating observed during injection. It was found that a good agreement between experimental and computational results was obtained only if the reaction was assumed to be more thermally sensitive than found in literature. The results from this study show that, during injection, the activation energy for degradation was 65 kcal/mol, compared to 17--30 kcal/mol found in literature for quiescent systems.

Garcia, Jose Luis

2000-10-01

215

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

Directory of Open Access Journals (Sweden)

Full Text Available In this study, not only Taguchi Method but also ANSYS in providing an economical and effective advance to the optimum design of the rib for a plastic injected product are introduced. The analytical model of a rectangular thermoplastic Acrylonitrile Butadiene Styrene (ABS plastic cover with rib of given thickness (2.8 mm was selected and constructed based on design experiences and the dimensions as well as the width of the rib were selected as the control factors for Taguchi Method. The deflection under a constant force of 150 Newton at the back centre of the cover was defined as quality characteristic. Additionally, the deformation experiment on a fixed thin beam was compared with the analytical result from ANSYS to verify the reliability of structure analysis from associated parameter setup and boundary condition operation. The L9(34 orthogonal array from Taguchi Method was moreover arranged to establish nine sets of finite element analysis models. Through Taguchi Method, the optimum design parameters were furthermore received from minimum deformation at back centre of the plastic cover analyzed by ANSYS. It is shown that the optimum structural parameters of a plastic rib can surely be effectively found with the integration of both Taguchi Method and ANSYS. Therefore, an Expert System of optimum design for various shapes of ribs can then be constructed through this study. This study exactly contributes a novel technique to the rib design for plastic injection industry in minimizing the development period of a new product.

Tian-Syung Lan

2008-01-01

216

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

DEFF Research Database (Denmark)

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

Tosello, Guido; Gava, Alberto

2009-01-01

217

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

218

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

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english High-strength copper alloys are used as materials for injection molding tools or as cores and inserts in steel molds because of their high thermal conductivity, corrosion and wear resistance. Unfortunately, there is little technological knowledge on the electrical discharge machining (EDM) of copper [...] -beryllium ASTM C17200 alloy. In this work, rough and finish machining conditions were tested using copper and tungsten-copper as materials for the electrodes. Cross-sectional micrographic and hardness examinations as well as surface roughness measurements were also carried out on workpieces after machining in order to study the thermally affected zones. Appropriate parameters settings for EDM of the investigated alloy are suggested.

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

219

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

Science.gov (United States)

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

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

2007-05-01

220

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-02-22

 
 
 
 
221

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.

Ã?stergaard, Peter Friis; Matteucci, Marco

2013-01-01

222

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

Scientific Electronic Library Online (English)

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

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

223

Effects of heat-moisture treatment on normal and waxy rice flours and production of thermoplastic flour materials.  

Science.gov (United States)

Different levels of heat-moisture treatment (HMT) were applied to normal and waxy rice flours. Changes in chemical composition and functional properties of both flours were investigated. It was found that HMT induced ?-turn conformation of rice proteins. Levels of HMT and types of rice flour interactively influenced thermal properties and XRD patterns of flour. When heat-moisture treated flour was utilized for production of thermoplastic flour (TPF) materials, it was found that HMT improved continuity of injection molding, complete mold filling, and yielded homogenous TPF materials. HMT levels affected the mechanical, thermal and barrier properties of TPF resin and materials differently. The ratio of HMT level to native flours was proposed for use not only for resin processing and injection molding, but also for improving mechanical and barrier properties of TPF materials. PMID:24751050

Khamthong, Prapaisut; Lumdubwong, Namfone

2012-09-01

224

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

Energy Technology Data Exchange (ETDEWEB)

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

Fuest, C.

1994-10-01

225

Nonlinear rheology and strain recovery of short chain branched polyolefin elastomers and thermoplastic olefin blends  

Science.gov (United States)

Polyolefin elastomers are random copolymers having a polyethylene backbone with the higher olefinic comonomer incorporated as short-chain branches. These random copolymers are widely used as polymer modifiers for thermoplastic materials such as polypropylenes, resulting in thermoplastic olefin (TPO) blends. This thesis addresses the nonlinear rheological behavior of the elastomers and then of the TPO blends. The effects of varying short chain branch density (SCB) on the melt rheology of three ethylene-octene random copolymers have been investigated. In particular, the strain-hardening behavior in extensional flow and strain recovery following nonlinear shear creep has been evaluated. The zero-shear viscosity followed trends in the backbone molecular weight closely. While the three copolymers were indistinguishable in linear viscoelastic creep and recovery, recovery following nonlinear shear creep decreased progressively with increasing SCB density. This reveals that the extent of rapid chain equilibration that occurs over Rouse time scales at higher strains was progressively lower with increasing SCB density. Strain hardening in uniaxial extensional flow was observed for all three copolymers. At strain rates below the primitive chain equilibration rates, strain hardening increases progressively with increasing SCB density. At higher rates, upon onset of primitive chain stretch, the strain hardening behavior for the three melts merges. Two thermoplastic olefin (TPO) blends were characterized in the context of injection molding; the surface morphology of injection molded tensile bars with these materials showed surface defects or flow marks to different extents. The flow marks were traced to different degrees of strain recovery in the dispersed phases of the two blends. This recovery occurred over injection molding timescales of the order of a few seconds. Strain recovery after shear creep was higher in the blend that displayed more severe flow marks in injection molding; the corresponding elastomer by itself also showed a greater extent of creep recovery. The quick strain recovery in the elastomer must be associated with elastic stresses rather than interfacial tension. A new experimental apparatus was assembled to study strain recovery after elongation of a model elastomer suspended in a less viscoelastic medium at room temperature. Small drops of well-characterized elastomers suspended in a matrix fluid of lower viscosity and elasticity, are stretched rapidly without wall effects in this setup; the stretch ratio of the drops is then recorded over time. Preliminary results confirm significant recovery over a few seconds. Exploration of the full range of parameters with this setup is left for future work.

Patham, Bhaskar

226

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

Energy Technology Data Exchange (ETDEWEB)

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

Zhang Haoming, E-mail: zhmustb@yahoo.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083 (China); He Xinbo [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083 (China); Qu Xuanhui [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Zhao Liming [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083 (China)

2009-11-25

227

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

International Nuclear Information System (INIS)

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

2009-11-25

228

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

229

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-05-15

230

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

International Nuclear Information System (INIS)

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

2010-01-01

231

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

Science.gov (United States)

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

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

2013-10-01

232

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

233

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1991-08-25

234

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

235

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

236

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

Scientific Electronic Library Online (English)

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

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

237

Injection molding WPC  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The use of wood-plastic composites, WPC, in commercial products is today limited. Current WPC products on the market are to a large extent limited to extruded products. There are strong reasons to increase the use of WPC. WPC can be manufactured from used plastic that otherwise cannot be recycled. This paper gives a brief description of the manufacturing of WPC, including wood filler treatment, the role of coupling agents and compounding. It describes the machinery used for producing WPC, and...

S T Clair Renard, Carl

2011-01-01

238

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1991-02-04

239

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

240

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

International Nuclear Information System (INIS)

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

2012-10-30

 
 
 
 
241

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-10-30

242

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1992-01-01

243

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

Science.gov (United States)

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

Weakley-Bollin, Shannon Christine

244

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

245

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.

246

Machining FEM model of long fiber composites for aeronautical components  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work is focused on the study of orthogonal cutting of long fiber composites. A model based in finite element was developed. The mechanisms of chip formation of Glass and Carbon Fiber Reinforced Polymer (FRP) composites were analyzed. Significant differences were observed when comparing machining induced damage predicted with the model for both materials. While damage extended widely ahead the interface and beneath the tool tip in the case of GFRP, damage was located in a much smaller zon...

Santuiste, Carlos; Soldani, Xavier; Migue?lez, Henar

2010-01-01

247

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

Science.gov (United States)

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

Yalcin, Baris

248

Effect of silica nanoparticles on reinforcement of poly(phenylene ether) based thermoplastic elastomer.  

Science.gov (United States)

Reinforcement of a novel poly(phenylene ether) (PPE) based thermoplastic elastomer (TPE), i.e., styrene-ethylene-butylene-styrene (SEBS)/ethylene vinyl acetate (EVA) and PPE-polystyrene (PS), was studied to develop a reinforced thermoplastic elastomer or thermoplastic vulcanizate (TPV). An effort was made to reinforce selectively the elastomeric dispersed phase of EVA by silica nanoparticles and silica sol-gel precursors, like alkoxy orthosilanes, using twin-screw extrusion and injection molding processes. Improvement of tensile strength and percent elongation at break was observed both with silica nanoparticles and tetraethoxy orthosilane (TEOS). Addition of TEOS transformed the dispersed EVA lamellar morphology into semispherical domains as a consequence of possible crosslinking. Soxhlet extraction was done on the silica and TEOS reinforced materials. The insoluble residues collected from both the silica and TEOS reinforced samples were analyzed in detail using both morphological and spectroscopic studies. This extensive study also provided an in-depth conceptual understanding of the PPE based TPE behavior upon reinforcement with silica nanoparticles and silica sol-gel precursors and the effect of reinforcement on recycling behavior. PMID:18572622

Gupta, Samik; Maiti, Parnasree; Krishnamoorthy, Kumar; Krishnamurthy, Raja; Menon, Ashok; Bhowmick, Anil K

2008-04-01

249

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1991-09-25

250

Effect of thermal history on the rheology of thermoplastic polyurethanes  

Science.gov (United States)

The effect of thermal history on the rheological behavior of ester- and, ether-based commercial thermoplastic polyurethanes (TPUs) was investigated. It was found from 1H and 13C nuclear magnetic resonance (NMR) spectroscopy that the ester-based TPU consisted of 4,4'-diphenylmethane diisocyanate (MDI) and butane diol (BDO) as hard segments and poly(butylene adipate) as soft segments, and the ether-based TPU consisted of MDT-BDO as hard segments and poly(oxytetramethylene) as soft segments. During isothermal annealing, the dynamic storage and loss moduli (G' and G'' ) of specimens, which had been prepared by injection molding at different temperatures, were monitored at a fixed angular frequency. It was found that thermal history of specimens had a profound influence on the variations of G' and G' ' with time observed during isothermal annealing. Isochronal dynamic temperature sweep experiments indicated that the TPUs exhibit hysteresis effect during heating and cooling, very similar to that observed in microphase-separated block polymers and thermotropic liquid-crystalline polymers reported in the literature. It was found that time-temperature superposition failed to produce reduced (or master) plots for the TPUs employed. This conclusion was reinforced by the temperature dependence of log G ' versus log G'' plots over the entire range of temperatures (110--190°C) investigated, suggesting that the morphological state of the TPU specimens varied with temperature. Little evidence was found from differential scanning calorimetry that thermal transitions took place in the TPU specimens during isothermal annealing, while values of G' and G' ' were found to vary with time. Measurements were taken of N-H stretching absorption bands in the Fourier transform infrared (FTIR) spectra during isothermal annealing at 170°C for specimens prepared by injection molding at different temperatures. The analysis of FTIR spectra indicated that variations of hydrogen bonding with time during isothermal annealing resemble very much variations of G' with time during isothermal annealing. Little evidence was found from 1H and 13C NMR spectroscopy that exchange reactions took place in the TPU specimens during isothermal annealing at elevated temperatures. It is concluded from the present study that microphase separation transition or order-disorder transition in TPU cannot be determined from oscillatory shear rheometry.

Yoon, Pil Joong

251

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-09-15

252

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-02-15

253

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-06-15

254

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-11-15

255

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

256

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,

257

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1992-01-01

258

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

Directory of Open Access Journals (Sweden)

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

Stefan Kirchberg

2013-04-01

259

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1993-09-30

260

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

 
 
 
 
261

Morphology of wood species affecting wood-thermoplastic interaction: microstructure and mechanical adhesion  

Directory of Open Access Journals (Sweden)

Full Text Available The main objective of the research presented here is to relate anatomical features of wood species that affect the interactions between polymeric phases and performance of wood plastic composites (WPC. These interactions are related to the probable interlocking volume and surface area for stress transfer in a WPC. Composites were produced from different wood species and analyzed using SEM (scanning electron microscopy. Results showed that wood species with high interfacial areas may increase mechanical interlocking, reflected in the viscous constant of the Maxwell model. A complicating factor is that the relation of cell wall thickness-lumen diameter and the interconnectivity between wood cells in a wood, affect the potential for cell collapse. When wood cells collapse, the penetration of the thermoplastic into the wood structure is almost always ceased. The collapse of wood cells during extrusion-injection molding processes reduced the potential surface for stress transfer between phases affecting the mechanical properties of composites. Undamaged wood cells may potentially be filled with HDPE thermoplastic enhancing modulus and increase the strength of WPC.

William Gacitua

2009-01-01

262

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-12-15

263

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

264

Effects of Cr and B Contents on Volume Fraction of (Cr,Fe)2B and Hardness in Fe-Based Alloys Used for Powder Injection Molding  

Science.gov (United States)

In the current study, Fe-based alloys were used for powder injection molding (PIM) parts with various qualities and hardness ranges by varying chemical compositions according to thermodynamically calculated phase diagrams. Their microstructure and hardness values were analyzed and compared with those of the PIM specimens made from conventional Fe-based alloy powders or stainless steel powders. The Cr-to-B ratio ( X Cr/ X B) and the sum of Fe, Cr, and B content ( X Fe+ X Cr+ X B) were varied to design nine Fe-based alloy compositions based on the composition of Armacor "M" alloy powders (Liquidmetal Technologies, Lake Forest, CA). According to the microstructural analysis results of the cast and heat-treated Fe-based alloys, large amounts of (Cr,Fe)2B were formed in the tempered martensite matrix. The volume fraction of (Cr,Fe)2B was varied from 42 pct to 91 pct with alloy compositions, and these results were well matched with the thermodynamically calculated volume fractions of (Cr,Fe)2B. The hardness of the fabricated alloys was varied from 300 VHN to 1600 VHN with alloy compositions, and this value increased linearly with the increasing volume fraction of (Cr,Fe)2B. From the correlation data between the volume fraction of (Cr,Fe)2B and hardness, the high-temperature equilibrium phase diagram, which could be used for the design of Fe-based alloys with various fractions and hardness values of (Cr,Fe)2B, was made.

Do, Jeonghyeon; Lee, Hyuk-Joong; Jeon, Changwoo; Ha, Dae Jin; Kim, Choongnyun Paul; Lee, Byeong-Joo; Lee, Sunghak; Shin, Yang Su

2012-07-01

265

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1999-02-22

266

Embranquecimento do polipropileno isotático injetado contendo TiO2 como pigmento / Whitening mechanism in injection molded polypropylene with TiO2 as pigment  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Descrevemos neste trabalho as causas e o mecanismo do embranquecimento de peças de polipropileno isotático injetado. Para isto foram injetados corpos de prova e placas com e sem estabilizantes. As amostras foram envelhecidas por exposição ambiental e em equipamento de envelhecimento acelerado (Weath [...] erometer). Foi feito o acompanhamento visual das peças para que pudessem ser caracterizadas quando começassem a embranquecer. A caracterização foi feita através de espectroscopia FT-IR por reflectância, Microscopia eletrônica de varredura, Microfluorescência de raios-X, Reflectância de luz e Microanálise de energia dispersiva (EDS) da superfície. Os espectros de infravermelho mostraram o aparecimento de diversos produtos de degradação como cetonas, aldeídos, ácidos carboxílicos, ésteres, perésteres e alfa-cetoésteres. Quando as amostras começaram a embranquecer foi verificada a formação de fissuras superficiais e o aumento da reflectância de luz para todos os comprimentos de onda do espectro. Concomitantemente foi verificado que a composição de superfície não é alterada pelo envelhecimento. A superfície não apresenta grande quantidade de partículas de TiO2 expostas. Conclui-se que o embranquecimento das peças é devido ao fissuramento superficial que aumenta a quantidade de luz refletida na superfície e não pela migração do pigmento. Abstract in english We studied in this work the whitening mechanism in injection molded polypropylene (PP), a problem usually manifested in car parts and particularly in car bumpers. For the development of this work we had samples (plaques and test samples) with and without antioxidants and ultraviolet stabilizers. The [...] se samples had been already aged by natural and artificial (Weatherometer equipment) exposure. In the natural aging samples were collected when the material started to whiten, after 3190, 4320 and 6190 h of exposure. In the artificial aging samples were collected after 415, 515 and 3000 h of exposure. The samples were characterized by visual observation, infrared spectroscopy, scanning electron microscopy, surface total light reflectance and titanium mapping in the samples cross section by X-ray microfluorescence and X-ray difraction of the TiO2 used in the formulation. When the samples start to whiten we observe the evolution of surface fissures which increase the surface roughness. This is followed by an increase in the total light reflection by the surface for all wavelengths. We observed that titanium is almost homogeneously distributed along samples cross section. In addition, we did not observe high concentration of exposed TiO2 on the surface. We conclude that the whitening phenomenon is a consequence of surface fissures evolution, which provides higher surface roughness and is followed by a higher surface diffuse light reflectance.

Dênison R. J., Maia; Marco-Aurelio, De Paoli.

267

Thermoplastic waves in magnetars  

CERN Document Server

Magnetar activity is generated by shear motions of the neutron star surface, which relieve internal magnetic stresses. An analogy with earthquakes and faults is problematic, as the crust is permeated by strong magnetic fields, which greatly constrain crustal displacements. We describe a new deformation mechanism that is specific to strongly magnetized neutron stars. The magnetically stressed crust begins to move because of a thermoplastic instability, which launches a wave that shears the crust and burns its magnetic energy. The propagating wave front resembles the deflagration front in combustion physics. We describe the conditions for the instability, the front structure and velocity, and discuss implications for observed magnetar activity.

Beloborodov, Andrei M

2014-01-01

268

Bonding thermoplastic polymers  

Science.gov (United States)

We demonstrate a new method for joining patterned thermoplastic parts into layered structures. The method takes advantage of case-II permeant diffusion to generate dimensionally controlled, activated bonding layers at the surfaces being joined. It is capable of producing bonds characterized by cohesive failure while preserving the fidelity of patterned features in the bonding surfaces. This approach is uniquely suited to production of microfluidic multilayer structures, as it allows the bond-forming interface between plastic parts to be precisely manipulated at micrometer length scales. The bond enhancing procedure is easily integrated in standard process flows and requires no specialized equipment.

Wallow, Thomas I. (Fremont, CA); Hunter, Marion C. (Livermore, CA); Krafcik, Karen Lee (Livermore, CA); Morales, Alfredo M. (Livermore, CA); Simmons, Blake A. (San Francisco, CA); Domeier, Linda A. (Danville, CA)

2008-06-24

269

Graphite fiber reinforced thermoplastic resins  

Science.gov (United States)

Mechanical properties of neat resin samples and graphite fiber reinforced samples of thermoplastic resins were characterized with particular emphasis directed to the effects of environmental exposure (humidity, temperature and ultraviolet radiation). Tensile, flexural, interlaminar shear, creep and impact strengths were measured for polysulfone, polyarylsulfone and a state-of-the-art epoxy resin samples. In general, the thermoplastic resins exhibited environmental degradation resistance equal to or superior to the reference epoxy resin. Demonstration of the utility and quality of a graphite/thermoplastic resin system was accomplished by successfully thermoforming a simulated compressor blade and a fan exit guide vane.

Novak, R. C.

1975-01-01

270

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1991-08-25

271

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-12-15

272

Irradiated thermoplastic elastomer  

International Nuclear Information System (INIS)

A thermoplastic elastomer which is processable after irradiation comprises a diblock copolymer which is irradiated at a dose level of from about 0.1 to about 3.0 times the gel dose. The resulting diblock copolymer elastomer has improved physical strength and is readily processable. The diblock copolymer has one block portion made from an olefin having from 2 to 12 carbon atoms, a conjugated diene having from 4 to 12 carbon atoms, or combinations thereof. The remaining block portion is made from vinyl aromatic monomers having from 3 to 15 carbon atoms. A triblock copolymer may be added to the diblock copolymer to form a blend which is irradiated at the same dose level. The triblock copolymer has a central block portion which is also made from the above-noted olefins, conjugated dienes, or combinations thereof, and end portions which are also made from the above-noted vinyl aromatic monomers. (Auth.)

1977-01-25

273

Processable Aromatic Polyimide Thermoplastic Blends  

Science.gov (United States)

Method developed for preparing readily-processable thermoplastic polyimides by blending linear, high-molecular-weight, polyimic acid solutions in ether solvents with ultrafine, semicrystalline, thermoplastic polyimide powders. Slurries formed used to make prepregs. Consolidation of prepregs into finsihed composites characterized by excellent melt flow during processing. Applied to film, fiber, fabric, metal, polymer, or composite surfaces. Used to make various stable slurries from which prepregs prepared.

Baucom, Robert M; Johnston, Norman J.; St. Clair, Terry L.; Nelson, James B.; Gleason, John R.; Proctor, K. Mason

1988-01-01

274

Micromechanical modeling of short glass-fiber reinforced thermoplastics-Isotropic damage of pseudograins  

International Nuclear Information System (INIS)

A micromechanical damage modeling approach is presented to predict the overall elasto-plastic behavior and damage evolution in short fiber reinforced composite materials. The practical use of the approach is for injection molded thermoplastic parts reinforced with short glass fibers. The modeling is proceeded as follows. The representative volume element is decomposed into a set of pseudograins, the damage of which affects progressively the overall stiffness and strength up to total failure. Each pseudograin is a two-phase composite with aligned inclusions having same aspect ratio. A two-step mean-field homogenization procedure is adopted. In the first step, the pseudograins are homogenized individually according to the Mori-Tanaka scheme. The second step consists in a self-consistent homogenization of homogenized pseudograins. An isotropic damage model is applied at the pseudograin level. The model is implemented as a UMAT in the finite element code ABAQUS. Model is shown to reproduce the strength and the anisotropy (Lankford coefficient) during uniaxial tensile tests on samples cut under different directions relative to the injection flow direction.

2011-05-04

275

Micromechanical modeling of short glass-fiber reinforced thermoplastics-Isotropic damage of pseudograins  

Science.gov (United States)

A micromechanical damage modeling approach is presented to predict the overall elasto-plastic behavior and damage evolution in short fiber reinforced composite materials. The practical use of the approach is for injection molded thermoplastic parts reinforced with short glass fibers. The modeling is proceeded as follows. The representative volume element is decomposed into a set of pseudograins, the damage of which affects progressively the overall stiffness and strength up to total failure. Each pseudograin is a two-phase composite with aligned inclusions having same aspect ratio. A two-step mean-field homogenization procedure is adopted. In the first step, the pseudograins are homogenized individually according to the Mori-Tanaka scheme. The second step consists in a self-consistent homogenization of homogenized pseudograins. An isotropic damage model is applied at the pseudograin level. The model is implemented as a UMAT in the finite element code ABAQUS. Model is shown to reproduce the strength and the anisotropy (Lankford coefficient) during uniaxial tensile tests on samples cut under different directions relative to the injection flow direction.

Kammoun, S.; Brassart, L.; Robert, G.; Doghri, I.; Delannay, L.

2011-05-01

276

Properties of Blends of Novatein Thermoplastic Protein from Bloodmeal and Polybutylene Succinate Using Two Compatibilizers  

Directory of Open Access Journals (Sweden)

Full Text Available The use of dual compatibilizers, poly (2-ethyl-2-oxazoline (PEOX and polymeric methylene diphenyl diisocyanate (pMDI in Novatein thermoplastic protein from bloodmeal (NTP and PBS blends were investigated. A composition of 50% of NTP was used for all formulations with different percentage compatibilizer. Mechanical, morphology, thermal and water absorption were used as analysis methods to study blend properties. To improve compatibility, two different approaches to blending the compatibilizers were used. Firstly, PEOX was added before extrusion this has improved the blend’s tensile strength. Secondly, addition of PEOX during NTP production followed by pMDI added before injection molding, showed a futher improvement in tensile strength. SEM revealed that PEOX has improved the dispersion of NTP and pMDI has strengthened the adhesion between phases consistent with mechanical property results. A broad tan ? peak in DMA analysis was obtained indicated improved compatibility in blends using two compatibilizers. In spite of that, the addition of dual compatibilizer has reduced the water resistance of PBS.

K. I. Ku Marsilla

2013-06-01

277

Fibroblastic response and surface characterization of O(2)-plasma-treated thermoplastic polyetherurethane.  

Science.gov (United States)

Injection-molded samples of thermoplastic polyetherurethane (TPU) were treated with low-temperature oxygen plasma for different processing times in order to enhance cellular attachment for a gastric implant. Its effects were investigated by contact angle measurement, surface topography, cytotoxicity and cell colonization tests. No significant changes were found in the surface roughness of plasma treatment with plasma treatment time of less than 5 min. Longer treatment showed significantly higher surface roughness. It seems that there was a link between the changes in contact angle and enhanced cell growth on the treated surface, although only for the range up to plasma treatment times of 3 min. Prolonged treatment times did not cause any major changes in the water contact angle, but strongly improved the number of growing cells on the surface. Plasma treatment for 3-7 min led to a twofold increase in the number of cells compared to untreated samples and did not significantly alter the WST-1 nor worsened the lactate dehydrogenase activity compared to the control. Thus, it appears that O(2) plasma treatment is a suitable surface modification method for a gastric implant made of TPU in order to improve surface cell attachment where 3-7 min is the recommended treatment time. PMID:20208128

Schlicht, Henning; Haugen, Håvard J; Sabetrasekh, Roya; Wintermantel, Erich

2010-04-01

278

Fibroblastic response and surface characterization of O2-plasma-treated thermoplastic polyetherurethane  

International Nuclear Information System (INIS)

Injection-molded samples of thermoplastic polyetherurethane (TPU) were treated with low-temperature oxygen plasma for different processing times in order to enhance cellular attachment for a gastric implant. Its effects were investigated by contact angle measurement, surface topography, cytotoxicity and cell colonization tests. No significant changes were found in the surface roughness of plasma treatment with plasma treatment time of less than 5 min. Longer treatment showed significantly higher surface roughness. It seems that there was a link between the changes in contact angle and enhanced cell growth on the treated surface, although only for the range up to plasma treatment times of 3 min. Prolonged treatment times did not cause any major changes in the water contact angle, but strongly improved the number of growing cells on the surface. Plasma treatment for 3-7 min led to a twofold increase in the number of cells compared to untreated samples and did not significantly alter the WST-1 nor worsened the lactate dehydrogenase activity compared to the control. Thus, it appears that O2 plasma treatment is a suitable surface modification method for a gastric implant made of TPU in order to improve surface cell attachment where 3-7 min is the recommended treatment time.

2010-04-01

279

Fibroblastic response and surface characterization of O{sub 2}-plasma-treated thermoplastic polyetherurethane  

Energy Technology Data Exchange (ETDEWEB)

Injection-molded samples of thermoplastic polyetherurethane (TPU) were treated with low-temperature oxygen plasma for different processing times in order to enhance cellular attachment for a gastric implant. Its effects were investigated by contact angle measurement, surface topography, cytotoxicity and cell colonization tests. No significant changes were found in the surface roughness of plasma treatment with plasma treatment time of less than 5 min. Longer treatment showed significantly higher surface roughness. It seems that there was a link between the changes in contact angle and enhanced cell growth on the treated surface, although only for the range up to plasma treatment times of 3 min. Prolonged treatment times did not cause any major changes in the water contact angle, but strongly improved the number of growing cells on the surface. Plasma treatment for 3-7 min led to a twofold increase in the number of cells compared to untreated samples and did not significantly alter the WST-1 nor worsened the lactate dehydrogenase activity compared to the control. Thus, it appears that O{sub 2} plasma treatment is a suitable surface modification method for a gastric implant made of TPU in order to improve surface cell attachment where 3-7 min is the recommended treatment time.

Schlicht, Henning; Wintermantel, Erich [Chair of Biomedical Engineering, Technische Universitaet Muenchen, Garching (Germany); Haugen, Haavard J; Sabetrasekh, Roya, E-mail: h.j.haugen@odont.uio.n [Department for Biomaterials, Faculty of Dentistry, University of Oslo, PO Box 1109 Blindern, 0317 Oslo (Norway)

2010-04-15

280

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

Directory of Open Access Journals (Sweden)

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

Edson N. Ito

2004-06-01

 
 
 
 
281

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

Scientific Electronic Library Online (English)

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

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

282

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-07-01

283

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1995-01-15

284

Thermoplastic starch materials prepared from rice starch  

International Nuclear Information System (INIS)

Rice starch is a source still little studied for the preparation of thermoplastic materials. However, its characteristics, such as the presence of proteins, fats and fibers may turn into thermoplastics with a better performance. The present study intends the evaluation of the viability of making starch thermoplastic from rice starch and glycerol as plasticizer. The results of X-ray diffraction and scanning electronic microscopy demonstrate the thermoplastic acquisition. The increase of plasticizer content brings on more hydrophilic thermoplastics with less resistance to tension and elongation at break. (author)

2009-10-13

285

Delamination prediction in orthogonal machining of carbon long fiber-reinforced polymer composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Machining processes of composites are common operations in industry involving elevated risk of damage generation in the workpiece. Long fiber reinforced polymer composites used in high-responsibility applications require safety machining operations guaranteeing workpiece integrity. Modeling techniques would help in the improvement of machining processes definition; however, they are still poorly developed for composites. The aim of this paper is advancing in the prediction of damage mechanism...

Santuiste, Carlos; Olmedo, A?lvaro; Soldani, Xavier; Migue?lez, Henar

2012-01-01

286

Rheological properties of olefinic thermoplastic elastomer blends:  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermoplastic Elastomers (TPE) are a class of materials that have rubber-like properties and can be processed like thermoplastic polymers. In this thesis, the rheological properties of two TPE blends are correlated to their morphology. The thermoplastic vulcanisates (TPV) consist of micron-sized, cured elastomer particles while the blends of PP and the triblock copolymer SEBS show co-continuous structures. Both blends also contain considerable amount of paraffinic oil.

Sengers, W. G. F.

2005-01-01

287

Solvent resistant thermoplastic composite matrices  

Science.gov (United States)

The following approaches improved the solvent resistance and raised the Tg of thermoplastics: end-capping aligomers with ethynyl groups; incorporating ethynyl groups pendent along the polymer chain; and correcting polymers containing pendent ethynyl groups with a low molecular weight diethynyl compound. The following conclusions were reached: (1) film and composite properties off an ethynyl-terminated sulfone were better than those of UDEL (trademark); (2) fracture energy of an ethynyl-terminated sulfone was lower than that of UDEL (trademark); (3) residual palladium in the cured ethynyl-terminated sulfone lower the thermooxidative stability of the cured resin; (4) the properties of a phenoxy resin were altered considerably by placing pendent ethynyl groups along the polymer chain; and (5) property trade-offs must be considered when thermoplastics are modified via reactant groups.

Hergenrother, P. M.; Jensen, B. J.; Havens, S. J.

1984-01-01

288

Thermoplastic composite bipolar plates for polymer electrolyte membrane fuel cells (PEMFC). Paper no. IGEC-1-089  

International Nuclear Information System (INIS)

Polymer electrolyte membrane fuel cells (PEMFC) are one significant component of the Hydrogen Economy. In order to make fuel cells economically feasible, processing and material cost need to be reduced. This reduction extends to the cost associated with bipolar plates. In an effort to produce functional bipolar plates at a competitive cost thermoplastic composite materials were extruded and injection molded, combining commercial materials such as polypropylene, carbon fiber, Vulcan carbon black, and acetylene carbon black. Two trials were executed. Trial 1 is a twenty sample experimental design and Trial 2 consists of different filler loadings with filler ratio 1:1:1. Thermal gravimetric analysis (TGA) was used to determine the actual filler loading following processing. Two methods of measuring electrical conductivity were investigated for Trial 1. Using method 1 a filler loading of 35 wt% and filler ratio of 1:1:1 reveals the best conductivity of 155 S/m. Method 2 has a maximum conductivity of 38 S/m and is achieved with a 32 wt% of only Vulcan carbon black. In Trial 2 a significant portion of the percolation curve for the filler ratio 1:1:1 is obtained. (author)

2005-06-12

289

Diamond turning of thermoplastic polymers  

Energy Technology Data Exchange (ETDEWEB)

Single point diamond turning studies were made using a series of thermoplastic polymers with different glass transition temperatures. Variations in surface morphology and surface roughness were observed as a function of cutting speed. Lower glass transition temperatures facilitate smoother surface cuts and better surface finish. This can be attributed to the frictional heating that occurs during machining. Because of the very low glass transition temperatures in polymeric compared to inorganic glasses, the precision machining response can be very speed sensitive.

Smith, E.; Scattergood, R.O.

1988-12-01

290

Melt electrospinning of thermoplastic polymers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This dissertation is concerned about developing of melt electrospinning strategies of thermoplastic polymers. The goal was to generate polypropylene nanofibers from the polymer melt instead from the polymer solution. Through this method, organic, toxic or environmentally non-friendly solvents can be avoided offering a clean process for nanofibers production. Melt electrospinning necessitates the use of polymer melts with lower melt viscosity since high melt viscosities inhibit the formation o...

2012-01-01

291

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

Directory of Open Access Journals (Sweden)

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

Marcos A d'Ávila

1997-12-01

292

MODIFICATION OF JACK PINE TMP LONG FIBERS BY ALKALINE PEROXIDE – PART 1. CHEMICAL CHARACTERISTICS OF FIBERS AND SPENT LIQUOR  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this work was to improve the quality of jack pine TMP long fibers, particularly with respect to the strength properties, by alkaline peroxide treatment. This paper reports the chemical characteristics of the treated long fibers and the spent liquors originating from various treatments. It was observed that, in comparison with hydrogen peroxide, the alkalinity of the treatment solutions had a greater influence on most fibre characteristics and spent liquor properties.

Ying Han

2008-08-01

293

Vibration Characteristics of Thermoplastic Composite  

Science.gov (United States)

Unreinforced, Long fiber and Short fiber polypropylene composites are being used in many antivibration applications, due to their time and temperature dependent specific mechanical properties. Their good damping behavior accounts for many engineering applications. For utilization of these materials in specific engineering applications, there is a need to understand the damping behavior of composites under dynamic load. For this work, unreinforced and 20% long and short reinforced glass fiber polypropylene composite materials were tested for forced transverse vibration damping characteristics under static as well as fatigue loading conditions. The damping characteristics are quantified by forced frequency response of the test material. Presence of reinforced fibers increases the damping capacity. Among reinforcements, short fiber reinforced polypropylene shows increased damping capacity then long glass fiber reinforced.

Haldar, Amit Kumar; Singh, Satnam; Prince, Prince

2011-12-01

294

Ultrasonic Assembly of Thermoplastic Parts  

Energy Technology Data Exchange (ETDEWEB)

Four ultrasonic methods were evaluated for assembly of experimental plastic parts for detonators: (1) welding, (2) crimping and staking, (3) insertion, and (4) reactivation of adhesives. For welding, staking and insertion, plastics with low elastic moduli, such as acrylics and polycarbonate, produced the best results. Thermosetting, hot-melt, and solution adhesives could all be activated ultrasonically to form good bonds on plastics and other materials. This evaluation indicated that thermoplastic detonator parts could be assembled ultrasonically in shorter times than by present production techniques with high bond strengths and high product acceptance rates.

Schurman, W. R.

1970-03-31

295

Thermoplastic resins for automotive applications  

Energy Technology Data Exchange (ETDEWEB)

Today`s high-performance thermoplastics could potentially shave up to 16 kg (35 lb) from the drivetrains, fuel systems, and chassis of future cars by replacing metal. In applications already commercial, weight savings average 20 to 25%, and it is not uncommon for installed cost of components to be 20 to 25% lower than machined castings, forgings, and stampings. Moreover, plastics have inherent processing and economic advantages in volume production, and will have for the foreseeable future. This article focuses on engineering resins that can satisfy challenging automotive design requirements, discusses selection criteria, and provides examples of metal-replacement applications.

Cronin, K. [Hoechst Technical Polymers, Summit, NJ (United States)

1997-05-01

296

Thermoplastic Elastomer Infill Synthetic Turf  

Directory of Open Access Journals (Sweden)

Full Text Available Synthetic – turf or Astroturf, is a grass-like man-made surface manufactured from synthetic polymers. It is most used for sports field and in residential area where natural grass is difficult to grow. Synthetic turf consist three basic components – grass filaments, Infill and backing. Grass filaments require softness and impact strength. Through several generations, grass filaments developed from initially nylon, polypropylene and now from polyethylene. Crumb rubber is used as infill material which contains toxic chemicals present in tyre. Some of the drawbacks of these materials can be solved by modifications in materials like by introduction of TPE –thermoplastic elastomer, which has been presented in this paper.

BHAKTI D.PATEL

2013-04-01

297

Avaliação do comportamento térmico por DSC na região da pele e do núcleo de amostras injetadas de nanocompósitos de poliamida 6/argila organofílica Polyamide 6/organoclay nanocomposites: evaluation of thermal behavior of injection molded samples by DSC  

Directory of Open Access Journals (Sweden)

Full Text Available Nanocompósitos de poliamida 6/argila organofílica foram preparados pelo método de intercalação por fusão. A argila foi tratada com o sal quaternário de amônio (Cetremide visando-se à obtenção da argila organofílica (OMMT. Esta foi caracterizada por fluorescência de raio X (FRX, Espectroscopia no Infravermelho (FTIR e Difração de Raio X (DRX. Os resultados dessas análises evidenciaram incorporação do sal entre as camadas da argila, tornando-a organofílica. Os nanocompósitos foram obtidos em extrusora de rosca dupla corrotacional, com 3% em peso de argila, e estes foram posteriormente injetados. A caracterização dos nanocompósitos por DRX mostrou uma estrutura esfoliada e/ou parcialmente esfoliada. As análises por Calorimetria Exploratória Diferencial (DSC foram realizadas nas regiões da pele (superfície e do núcleo (centro dos corpos de prova e, mostraram as fases cristalinas ? e ? na pele e apenas a fase ? no núcleo e que o grau de cristalinidade na pele foi menor do que no núcleo.Polyamide 6/organoclay nanocomposites were prepared using the melt intercalation technique. The clay was treated with a quaternary ammonium salt (Cetremide to obtain the organoclay (OMMT, which was characterized with X ray fluorescence (XRF, Infrared Spectroscopy (FTIR and X ray diffraction (XRD. The results of these analyses showed the incorporation of the salt in the clay structure, confirming the organophilization. The nanocomposites were obtained in a co-rotational twin screw extruder with 3 wt. (% of clay, and then the pellets were injection molded. The characterization by XRD of the nanocomposites showed an exfoliated and/or partially exfoliated structure. The analysis by DSC were made in the skin and core regions of the samples, showing the ? and ?-crystalline forms in the skin and only the ?-form in the core region. The degree of crystallinity in the skin was lower than in the core.

Renê A. da Paz

2010-01-01

298

Avaliação do comportamento térmico por DSC na região da pele e do núcleo de amostras injetadas de nanocompósitos de poliamida 6/argila organofílica / Polyamide 6/organoclay nanocomposites: evaluation of thermal behavior of injection molded samples by DSC  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Nanocompósitos de poliamida 6/argila organofílica foram preparados pelo método de intercalação por fusão. A argila foi tratada com o sal quaternário de amônio (Cetremide) visando-se à obtenção da argila organofílica (OMMT). Esta foi caracterizada por fluorescência de raio X (FRX), Espectroscopia no [...] Infravermelho (FTIR) e Difração de Raio X (DRX). Os resultados dessas análises evidenciaram incorporação do sal entre as camadas da argila, tornando-a organofílica. Os nanocompósitos foram obtidos em extrusora de rosca dupla corrotacional, com 3% em peso de argila, e estes foram posteriormente injetados. A caracterização dos nanocompósitos por DRX mostrou uma estrutura esfoliada e/ou parcialmente esfoliada. As análises por Calorimetria Exploratória Diferencial (DSC) foram realizadas nas regiões da pele (superfície) e do núcleo (centro) dos corpos de prova e, mostraram as fases cristalinas ? e ? na pele e apenas a fase ? no núcleo e que o grau de cristalinidade na pele foi menor do que no núcleo. Abstract in english Polyamide 6/organoclay nanocomposites were prepared using the melt intercalation technique. The clay was treated with a quaternary ammonium salt (Cetremide) to obtain the organoclay (OMMT), which was characterized with X ray fluorescence (XRF), Infrared Spectroscopy (FTIR) and X ray diffraction (XRD [...] ). The results of these analyses showed the incorporation of the salt in the clay structure, confirming the organophilization. The nanocomposites were obtained in a co-rotational twin screw extruder with 3 wt. (%) of clay, and then the pellets were injection molded. The characterization by XRD of the nanocomposites showed an exfoliated and/or partially exfoliated structure. The analysis by DSC were made in the skin and core regions of the samples, showing the ? and ?-crystalline forms in the skin and only the ?-form in the core region. The degree of crystallinity in the skin was lower than in the core.

Paz, Renê A. da; Leite, Amanda M. D.; Araújo, Edcleide M.; Melo, Tomas J. A.; Pessan, Luiz A..

299

Avaliação da orientação molecular de moldados de polipropileno utilizando figuras de pólo obtidas por difração de raios X / Evaluation of the molecular orientation of injection molded polypropylene using X-ray pole figures  

Scientific Electronic Library Online (English)

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

Álvaro M., Almeida; Márcia C., Branciforti; Rosario E. S., Bretas.

300

Implementation of New Process Models for Tailored Polymer Composite Structures into Processing Software Packages  

Energy Technology Data Exchange (ETDEWEB)

This report describes the work conducted under the Cooperative Research and Development Agreement (CRADA) (Nr. 260) between the Pacific Northwest National Laboratory (PNNL) and Autodesk, Inc. to develop and implement process models for injection-molded long-fiber thermoplastics (LFTs) in processing software packages. The structure of this report is organized as follows. After the Introduction Section (Section 1), Section 2 summarizes the current fiber orientation models developed for injection-molded short-fiber thermoplastics (SFTs). Section 3 provides an assessment of these models to determine their capabilities and limitations, and the developments needed for injection-molded LFTs. Section 4 then focuses on the development of a new fiber orientation model for LFTs. This model is termed the anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model as it explores the concept of anisotropic rotary diffusion to capture the fiber-fiber interaction in long-fiber suspensions and uses the reduced strain closure method of Wang et al. to slow down the orientation kinetics in concentrated suspensions. In contrast to fiber orientation modeling, before this project, no standard model was developed to predict the fiber length distribution in molded fiber composites. Section 5 is therefore devoted to the development of a fiber length attrition model in the mold. Sections 6 and 7 address the implementations of the models in AMI, and the conclusions drawn from this work is presented in Section 8.

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

2010-02-23

 
 
 
 
301

Implementation of New Process Models for Tailored Polymer Composite Structures into Processing Software Packages  

International Nuclear Information System (INIS)

This report describes the work conducted under the Cooperative Research and Development Agreement (CRADA) (Nr. 260) between the Pacific Northwest National Laboratory (PNNL) and Autodesk, Inc. to develop and implement process models for injection-molded long-fiber thermoplastics (LFTs) in processing software packages. The structure of this report is organized as follows. After the Introduction Section (Section 1), Section 2 summarizes the current fiber orientation models developed for injection-molded short-fiber thermoplastics (SFTs). Section 3 provides an assessment of these models to determine their capabilities and limitations, and the developments needed for injection-molded LFTs. Section 4 then focuses on the development of a new fiber orientation model for LFTs. This model is termed the anisotropic rotary diffusion - reduced strain closure (ARD-RSC) model as it explores the concept of anisotropic rotary diffusion to capture the fiber-fiber interaction in long-fiber suspensions and uses the reduced strain closure method of Wang et al. to slow down the orientation kinetics in concentrated suspensions. In contrast to fiber orientation modeling, before this project, no standard model was developed to predict the fiber length distribution in molded fiber composites. Section 5 is therefore devoted to the development of a fiber length attrition model in the mold. Sections 6 and 7 address the implementations of the models in AMI, and the conclusions drawn from this work is presented in Section 8.

2010-01-01

302

Tough soluble aromatic thermoplastic copolyimides  

Science.gov (United States)

Tough, soluble, aromatic, thermoplastic copolyimides were prepared by reacting 4,4'-oxydiphthalic anhydride, 3,4,3',4'-biphenyltetracarboxylic dianhydride and 3,4'-oxydianiline. Alternatively, these copolyimides may be prepared by reacting 4,4'-oxydiphthalic anhydride with 3,4,3',4'-biphenyltetracarboxylic dianhydride and 3,4'-oxydiisocyanate. Also, the copolyimide may be prepared by reacting the corresponding tetra acid and ester precursors of 4,4'-oxydiphthalic anhydride and 3,4,3',4'-biphenyltetracarboxylic dianhydride with 3,4'-oxydianiline. These copolyimides were found to be soluble in common amide solvents such as N,N'-dimethyl acetamide, N-methylpyrrolidinone, and dimethylformamide allowing them to be applied as the fully imidized copolymer and to be used to prepare a wide range of articles.

Bryant, Robert G. (Inventor)

2000-01-01

303

Voltage control for corona charging thermoplastics  

Science.gov (United States)

Controlled voltage is accomplished by placing metal plate with hole in it near surface of film. During charging, thermoplastic will accumulate charge only until it reaches plate voltage; after that, all charge will be deflected to plate.

Mezrich, R. S.

1976-01-01

304

Process for preparing thermoplastic aromatic polyimides  

Science.gov (United States)

A method of preparing insoluble thermoplastic aromatic polyimides is described, having uniquely low softening temperatures by reacting, in a suitable solvent, an aromatic dianhydride, and a meta-substituted aromatic diamine.

Bell, V. L. (inventor)

1978-01-01

305

Sulfur Mustard Penetration of Thermoplastic Elastomers.  

Science.gov (United States)

Resistance to sulfur mustard (HD) penetration was investigated for two commercially available thermoplastic elastomers, Santoprene and Alcryn. To pass the Liquid Agent Vapour Penetration Test (LAVPT), Santoprene sheet needed to be at least 1.03 mm thick w...

P. Miller

2008-01-01

306

142.2km BOTDA based on ultra-long fiber laser with a ring cavity  

Science.gov (United States)

A novel distributed Raman amplification (DRA) scheme based on ultra-long fiber laser (UL-FL) pumping with a ring cavity rather than a linear cavity is proposed and demonstrated, for the first time. As a typical application of the proposed configuration, ultra-long-distance distributed sensing with Brillouin optical time-domain analysis (BOTDA) over 142.2km fiber with 5m spatial resolution and +/- 1.5° temperature uncertainty is achieved, without any repeater, for the first time. The key point for the significant performance improvement is the system could offer both of uniform gain distribution and considerably suppressed pump-probe relative intensity noise (RIN) transfer, by optimized design of system structure and parameters.

Jia, Xin-Hong; Rao, Yunjiang; Wang, Zi-Nan; Zhang, Wei-Li; Yuan, Cheng-Xu; Yan, Xiao-Dong; Li, Jin; Wu, Han; Zhu, Ye-Yu; Peng, Fei

2013-09-01

307

Vector rectangular-shape laser based on reduced graphene oxide interacting with long fiber taper  

CERN Document Server

A vector dual-wavelength rectangular-shape laser (RSL) based on a long fiber taper deposited with reduced graphene oxide is proposed, where the nonlinearity is enhanced due to large evanescent-field-interacting length and strong field confinement of a 8 mm fiber taper with a waist diameter of 4 micronmeters. Graphene flakes are deposited uniformly on the taper waist with light pressure effect, so this structure guarantees both excellent saturable absorption and high nonlinearity. The RSL with a repetition rate of 7.9 MHz exhibits fast polarization switching in two orthogonal polarization directions, and the temporal and spectral characteristics are investigated. The results suggest that the long taper-based graphene structure is an efficient choice for nonlinear devices.

Gao, Lei; Zeng, Jing; Huang, Wei; Liu, Min

2014-01-01

308

Maleated thermoplastic starch by reactive extrusion  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Novel maleated thermoplastic starch (MTPS) with both improved processing and reactivity useful in the melt-blending with biodegradable polyester was prepared through in situ reactive modification of thermoplastic starch (TPS) with maleic anhydride (MA) as esterification agent. Glycerol was used as plasticizer. Physico-chemical parameters of MTPS were determined at different MA contents, while keeping both the content in glycerol (20 wt% by starch), and the processing temperature constant (150...

2008-01-01

309

Tough, High-Performance, Thermoplastic Addition Polymers  

Science.gov (United States)

Series of addition-type thermoplastics (ATT's) exhibit useful properties. Because of their addition curing and linear structure, ATT polymers have toughness, like thermoplastics, and easily processed, like thermosets. Work undertaken to develop chemical reaction forming stable aromatic rings in backbone of ATT polymer, combining high-temperature performance and thermo-oxidative stability with toughness and easy processibility, and minimizing or eliminating necessity for tradeoffs among properties often observed in conventional polymer syntheses.

Pater, Ruth H.; Proctor, K. Mason; Gleason, John; Morgan, Cassandra; Partos, Richard

1991-01-01

310

Moldagem por injeção em baixa pressão de peças complexas de cerâmicas avançadas produzidas com pós submicrométricos / Low-pressure injection molding of complex parts of advanced ceramic produced with fine powder  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese A moldagem por injeção em baixa pressão (MIBP) tem constituído, nos últimos anos, uma excelente alternativa para a produção de pequenos lotes de peças cerâmicas diversificadas e com formas complexas. Esta técnica de conformação é relativamente simples e barata, mas apresenta diversos problemas na et [...] apa de extração dos ligantes, principalmente quando o pó cerâmico é muito fino e as peças possuem grande seção transversal. Neste trabalho é descrita uma metodologia específica para a produção de peças cerâmicas por moldagem por injeção a baixa pressão de alumina submicrométrica (0,4 mim), incluindo a formulação da mistura para injeção, bem como detalhes do processo de extração dos ligantes orgânicos utilizados na moldagem. Para o desenvolvimento deste processo fez-se necessário (i) entender melhor o processo de MIBP, (ii) desenvolver a formulação da mistura de pó cerâmico e aditivos orgânicos, (iii) confeccionar moldes adequados para a injeção a baixas pressões e (iv) otimizar os parâmetros de injeção. A metodologia desenvolvida neste trabalho, possibilita a confecção de peças cerâmicas complexas, com seção transversal relativamente grande, permitindo uma produção robusta de pequenos lotes de peças cerâmicas diversificadas com ótima qualidade e excelente reprodutibilidade. Abstract in english In the past years, low-pressure injection molding (LPIM) has been a good alternative for the production of small batches of diversified complex shapes ceramic parts. This molding technique is relatively simple and cheap, but presents several problems related to debinding, especially for fine ceramic [...] particle, and large cross-section ceramic pieces. In this work, we present a metodology for the production of ceramic parts based on the LPIM of submicrometer-sized alumina powder (0.4 mum). The binder formulation is described, as well as the details of the debinding stage. For the development of this process it was necessary (i) to achieve a better understanding of the LPIM process, (ii) develop the binder formulation and to find the better proportion for the binder plus ceramic powder mixture, (iii) to prepare molds suitable for LPIM and (iv) to optimize the injection parameters. The procedure here reported makes it possible to produce complex shape ceramic parts, with relatively large cross-section, allowing the robust production of small batches of diversified ceramic parts, with high quality and excellent reproducibility.

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

311

Moldagem por injeção em baixa pressão de peças complexas de cerâmicas avançadas produzidas com pós submicrométricos Low-pressure injection molding of complex parts of advanced ceramic produced with fine powder  

Directory of Open Access Journals (Sweden)

Full Text Available A moldagem por injeção em baixa pressão (MIBP tem constituído, nos últimos anos, uma excelente alternativa para a produção de pequenos lotes de peças cerâmicas diversificadas e com formas complexas. Esta técnica de conformação é relativamente simples e barata, mas apresenta diversos problemas na etapa de extração dos ligantes, principalmente quando o pó cerâmico é muito fino e as peças possuem grande seção transversal. Neste trabalho é descrita uma metodologia específica para a produção de peças cerâmicas por moldagem por injeção a baixa pressão de alumina submicrométrica (0,4 mim, incluindo a formulação da mistura para injeção, bem como detalhes do processo de extração dos ligantes orgânicos utilizados na moldagem. Para o desenvolvimento deste processo fez-se necessário (i entender melhor o processo de MIBP, (ii desenvolver a formulação da mistura de pó cerâmico e aditivos orgânicos, (iii confeccionar moldes adequados para a injeção a baixas pressões e (iv otimizar os parâmetros de injeção. A metodologia desenvolvida neste trabalho, possibilita a confecção de peças cerâmicas complexas, com seção transversal relativamente grande, permitindo uma produção robusta de pequenos lotes de peças cerâmicas diversificadas com ótima qualidade e excelente reprodutibilidade.In the past years, low-pressure injection molding (LPIM has been a good alternative for the production of small batches of diversified complex shapes ceramic parts. This molding technique is relatively simple and cheap, but presents several problems related to debinding, especially for fine ceramic particle, and large cross-section ceramic pieces. In this work, we present a metodology for the production of ceramic parts based on the LPIM of submicrometer-sized alumina powder (0.4 mum. The binder formulation is described, as well as the details of the debinding stage. For the development of this process it was necessary (i to achieve a better understanding of the LPIM process, (ii develop the binder formulation and to find the better proportion for the binder plus ceramic powder mixture, (iii to prepare molds suitable for LPIM and (iv to optimize the injection parameters. The procedure here reported makes it possible to produce complex shape ceramic parts, with relatively large cross-section, allowing the robust production of small batches of diversified ceramic parts, with high quality and excellent reproducibility.

J. E. Zorzi

2004-09-01

312

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

313

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.

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

314

Comparison between Palm Oil Derivative and Commercial Thermo-Plastic Binder System on the Properties of the Stainless Steel 316L Sintered Parts  

Science.gov (United States)

Binder system is one of the most important criteria for the powder injection molding (PIM) process. Failure in the selection of the binder system will affect on the final properties of the sintered parts. The objectives of this studied is to develop a novel binder system based on the local natural resources and environmental friendly binder system from palm oil derivative which is easily available and cheap in our country of Malaysia. The novel binder that has been developed will be replaced the commercial thermo-plastic binder system or as an alternative binder system. The results show that the physical and mechanical properties of the final sintered parts fulfill the Metal Powder Industries Federation (MPIF) standard 35 for PIM parts. The biocompatibility test using cell osteosarcoma (MG63) and vero fibroblastic also shows that the cell was successfully growth on the sintered stainless steel 316L parts indicate that the novel binder was not toxic. Therefore, the novel binder system based on palm oil derivative that has been developed as a binder system fulfills the important criteria for the binder system in PIM process.

Ibrahim, R.; Azmirruddin, M.; Wei, G. C.; Fong, L. K.; Abdullah, N. I.; Omar, K.; Muhamad, M.; Muhamad, S.

2010-03-01

315

Development of Lignin-Based Polyurethane Thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

In our continued effort to develop value-added thermoplastics from lignin, here we report utilizing a tailored feedstock to synthesize mechanically robust thermoplastic polyurethanes at very high lignin contents (75 65 wt %). The molecular weight and glass transition temperature (Tg) of lignin were altered through cross-linking with formaldehyde. The cross-linked lignin was coupled with diisocyanate-based telechelic polybutadiene as a network-forming soft segment. The appearance of two Tg s, around 35 and 154 C, for the polyurethanes indicates the existence of two-phase morphology, a characteristic of thermoplastic copolymers. A calculated Flory-Huggins interaction parameter of 7.71 also suggests phase immiscibility in the synthesized lignin polyurethanes. An increase in lignin loading increased the modulus, and an increase in crosslink-density increased the modulus in the rubbery plateau region of the thermoplastic. This path for synthesis of novel lignin-based polyurethane thermoplastics provides a design tool for high performance lignin-based biopolymers.

Saito, Tomonori [ORNL; Perkins, Joshua H [ORNL; Jackson, Daniel C [ORNL; Trammell, Neil E [ORNL; Hunt, Marcus A [ORNL; Naskar, Amit K [ORNL

2013-01-01

316

A Solvent-Resistant, Thermoplastic Poly(imidesulfone)  

Science.gov (United States)

Process for preparing thermoplastic poly(imidesulfone) results in material having excellent thermoplastic properties generally associated with polysulfones and excellent solvent resistance generally associated with polyimides. New thermoplastic, solvent-resistant polymer is used as molding resin, as adhesive, and as matrix resin for fiber reinforced composites.

St. Clair, T. L.; Yamaki, D.

1983-01-01

317

Induced mutation of Egypt cotton variety and selection of long fiber cotton mutant by irradiation  

International Nuclear Information System (INIS)

In order to obtain long fiber cotton variety which would be adaptable to the ecological conditions of Yellow River Region, the mutation induction of Egypt cotton variety, Ashmouni, was carried out by ?-ray of 279 Gy in 1985. In M1 generation, serious radiation damage was shown in seed-lings, the death percentage of seedling was 63.3%. Two plants with early maturity were selected and their seeds were planted individually in 1986. The complex segregation appeared in M2 generation. The selection and domestication were carried out for several years and four stable mutant lines which included early maturity, dwarf plant, compact pattern, stranger bollbearing ability as well as upland cotton characters were obtained in 1991. The fiber length of these lines reached 33 ? 35 mm, and the mutants were adaptable to ecological condition in Shandong Province. The mutant line, 90197-1, whose growing period and plant height shorter than those of upland cotton cultivar, Zhong-mian No.12, has compact plant pattern, high bollbearing ability and ginning out turn of about 40%. Further yield test is required for these lines. The hereditary variability of the progeny in mutated Egypt cotton variety, preliminary cytological observation and the analysis of isoenzyme in mutants are also discussed

1994-03-01

318

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.

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

319

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  

Directory of Open Access Journals (Sweden)

Full Text Available A evolução da morfologia de fases em blendas não reativas e reativas de poliamida-6 com copolímero de acrilonitrila/EPDM/estireno (AES em uma extrusora de rosca dupla co-rotacional foi investigada. A evolução da morfologia de fases ao longo da extrusora de rosca dupla foi monitorada através da coleta 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.The evolution of phase morphology in non-reactive vs reactive blends with polyamide and ethylene-propylene-diene elastomer grafted with styrene-acrylonitrile copolymer (AES in a co-rotating twin-screw extruder was investigated. The morphological evolution of these blends along a twin-screw extruder was monitored by quickly collecting small samples from the melt at specific extruder barrel locations and characterizing them with a transmission electron microscope (TEM. The copolymers methyl methacrylate-co-maleic anhydride (MMA-MA and methyl methacrylate-co-glycidyl methacrylate (MMA-GMA were used as compatibilizing agents. The maleic anhydride and the epoxy groups of the copolymers can react with the polyamide end groups during melt processing and improve the interphase interaction in the PA6/AES system. The uncompatibilized blends showed a coarse phase morphology where the AES phase is not well dispersed in the PA6 matrix due to lack of adequate interaction between the components. The addition of MMA-GMA compatibilizer neither promoted good phase dispersion or improved the mechanical properties of the blends, probably because the possible reactions are very slow and may not occur inside the extruder. On the other hand, the addition of the MMA-MA copolymer promotes better impact strength and good phase dispersion in the blend. The AES particles undergo significant reduction in the first stages of the mixture inside the extruder. The morphology observed for the injection molded specimens was correlated with the mechanical properties.

Adriane Bassani

2005-07-01

320

Assembly injection moulding joins metal and thermoplastics; Montagespritzgiessen verbindet Metall und Thermoplast  

Energy Technology Data Exchange (ETDEWEB)

Automotive safety restraint system components increasingly use flexible styrenic and olefinic TPEs. With continued evolution in automotive interior design and performance requirements, demands on material technology are concomitantly rising. A growing trend towards molded in color solutions with low gloss aesthetics require TPE materials with ery low gloss, improved scratch resistance, and low temperature ductility. Innovations utilizing Teknor Apex's compounding technology have enabled the development of low gloss styrenic elastomers for airbag door applications that provide an optimized combination of low temperature performance, surface aesthetics (low gloss and improved scratch resistance), and ease of processing. This paper highlights the salient features of these new compounds and the effect of injection molding condition on the gloss at the surface of the cover.

Drummer, Dietmar; Meister, Steve [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Kunststofftechnik; Reichart, Marc [HBW Gubesch Kunststoff Engineering GmbH, Wilhelmsdorf (Germany)

2010-03-08

 
 
 
 
321

Inelastic behavior of thermoplastic composites  

Energy Technology Data Exchange (ETDEWEB)

The mechanical behaviors of AS4 reinforced PEKK-based composites were studied. These new thermoplastic composite systems developed by Du Pont exhibit pronounced nonlinear and time dependent behaviors. To characterize the inelastic behavior, classical plasticity and creep theory have been adopted and modified for the orthotropic case by using a one-parameter potential function. The elastic-plastic behavior of LDF(TM) AS-4/PEKK system employing aligned, long discontinuous fiber reinforced composites has been studied in comparison with the continuous fiber reinforced counterpart. A dual mode plastic potential action was employed to model the plastic behaviors of these composites at room and elevated temperatures up to 177 C. A one-parameter failure criterion was also applied to predict the failure strength. Off-axis coupon specimens were used to measure the failure strength and generate stress-strain curves from which the elastic-plastic properties were extracted. It was observed that the elastic-plastic performance and strength of LDF(TM) are as good as those of the continuous fiber system. The material constants were determined by using uniaxial creep tests of off-axis coupon specimens. In terms of effective stress and effective creep strain, the anisotropic creep behavior was described by a stress dependent master creep curve irrespective of loading direction relative to fiber orientation. This model was implemented into classical laminate theory to predict the creep behavior of composite laminate, and compared with experimental data of (+/- 45)4s laminate specimens. The influence of thermal stress was included. The micromechanical approach also was tried to model the inelastic behavior of continuous fiber reinforced composites. The fiber was assumed to be orthotropically elastic, and the matrix to conform to the classical elastic-plasticity and creep theories.

Chung, I.

1992-01-01

322

Deformational characteristics of thermoplastic elastomers  

Science.gov (United States)

This thesis focuses primarily on the structure-property relationships of poly (styrene-ethylene-butylene-styrene) triblock copolymer TPEs. First evidence for strain-induced crystallization occurring in certain SEBS block copolymers has been established using unique techniques like deformation calorimetry, combined in-situ small angle X-ray and wide angle X-ray diffraction (SAXD/WAXD). Also the ramifications of such strain-induced crystallization on the mechanical properties like cyclic hysteresis, stress relaxation/creep retention of these SEBS systems have been studied. In addition, the structural changes in the morphology of these systems on deformation have been investigated using combined SAXD/WAXD setup. Small angle X-ray diffraction probed the changes at the nano-scale of polystyrene (PS) cylinders, while wide angle X-ray diffraction probed the changes at molecular length scales of the amorphous/crystalline domains of the elastomeric mid-block in these systems. New structural features at both these length scales have been observed and incorporated into the overall deformation mechanisms of the material. Continuous processing techniques like extrusion have been used to obtain ultra long-range order and orientation in these SEBS systems. Thus well ordered crystal like hexagonal packing of cylinders, where in each element in this hexagonal lattice can be individually addressed without any grain boundaries can be realized using these robust techniques. The effect of long-range order/orientation on the mechanical properties has been studied. In addition, these well ordered systems serve as model systems for evaluating deformation mechanisms of these SEBS systems, where the relative contributions of each of the phases can be estimated. EPDM/i-PP thermoplastic vulcanizates (TPVs) have micron size scale phase separated morphologies of EPDM rubber dispersed in a semicrystalline i-PP matrix as a result of the dynamic vulcanization process. Confocal microscopy studies, along with scanning electron microscopy (SEM) studies show that the morphology of these EPDM/i-PP systems resembles a microcellular "filled" foam in which i-PP occupies the strut regions and EPDM the inner core. Based on this, an analytical model has been developed that takes into account composition information, molecular weight, cure state and morphology into account.

Indukuri, Kishore K.

323

Apparatus for thermoforming thermoplastic sheet materials  

Energy Technology Data Exchange (ETDEWEB)

The present invention relates to an improved plug or tool for use in the production of shaped articles from thermoplastic sheet materials. An important feature of the present invention is that the tool or plug comprises a body portion which incorporates one or more inserts which possess a thermal conductivity different from the thermal conductivity of the body portion.

Bullock, L.W.; Kovacs, F.; Vlahek, J.

1985-02-19

324

Glass transition temperature of thermoplastic starches  

Directory of Open Access Journals (Sweden)

Full Text Available Thermoplastic starch was produced by mixing potato starch and glycerol in a single screw extruder. The glass transition temperatures of the materials obtained were measured by differential scanning calorimetry (DSC. Both the influence of extruder parameters and material parameters, such as moisture and glycerol content and amyloses/amylopectine ratio were investigated. Repeated extrusion cycles affect the glass transition temperature only to a very small extent.

M. Mitrus

2005-09-01

325

Polyether Based Thermoplastic Polyurethane Melt Blown Nonwovens  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A series of melt blown samples were produced from three hardness grades of ether based thermoplastic polyurethane elastomers (TPU). The fabrics were tested to investigate their structure-property relationship in a melt blown process. Solution viscosities of the web were only 20-26% of there original values indicating a large loss in polymer molecular weight during melt blowing. Fiber diameter distributions measured on melt blown samples were found comparable to those made with more convention...

2006-01-01

326

Silane Crosslinked Wood-Thermoplastic Composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wood-thermoplastic composites are a more environmental friendly alternative for pressure-treated lumber but can also replace engineering plastic products. These composites have been on the market for more than ten years now and have mainly been used in building and automotive applications. The use of these materials has shown that long-term properties, durability, and toughness are the main problems. The aim of this study was to investigate if silane crosslinking could be one way of solving t...

Bengtsson, Magnus

2005-01-01

327

Silane Crosslinked Wood-Thermoplastic Composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wood-thermoplastic composites are a more environmental friendly alternative for pressure-treated lumber but can also replace engineering plastic products. These composites have been on the market for more than ten years now and have mainly been used in building and automotive applications. The use of these materials has shown that long-term properties, durability, and toughness are the main problems. The aim of this study was to investigate if silane crosslinking could be one way of...

2005-01-01

328

Thermoplastic composite cylinders for underwater applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A study of thermoplastic matrix composites has been performed to investigate their use in underwater applications such as oceanography, submarine, and sub-sea offshore structures. This article first presents six candidate materials. Results from simple mechanical and seawater aging screening tests on flat specimens are then described. Glass/epoxy and carbon/epoxy composites are used as reference materials. Two materials emerged from this process, glass/PEI and carbon/PEEK. Cylinders of both w...

Davies, Peter; Riou, Luc; Mazeas, Florence; Warnier, Philippe

2005-01-01

329

Fabrication of the Thermoplastic Microfluidic Channels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In our lab, we have successfully isolated nucleic acids directly from microliter and submicroliter volumes of human blood, urine and stool using polymer/nanoparticle composite microscale lysis and solid phase extraction columns. The recovered samples are concentrated, small volume samples that are PCRable, without any additional cleanup. Here, we demonstrate how to fabricate thermoplastic microfluidic chips using hot embossing and heat sealing. Then, we demonstrate how to use in situ light di...

Bhattacharyya, Arpita; Kulinski, Dominika; Klapperich, Catherine

2008-01-01

330

Thermoforming of Continuous Fibre Reinforced Thermoplastic Composites  

International Nuclear Information System (INIS)

The introduction of new materials, particularly for aerospace products, is not a simple, quick or cheap task. New materials require extensive and expensive qualification and must meet challenging strength, stiffness, durability, manufacturing, inspection and maintenance requirements. Growth in industry acceptance for fibre reinforced thermoplastic composite systems requires the determination of whole life attributes including both part processing and processed part performance data. For thermoplastic composite materials the interactions between the processing parameters, in-service structural performance and end of life recyclability are potentially interrelated. Given the large number and range of parameters and the complexity of the potential relationships, understanding for whole life design must be developed in a systematic building block approach. To assess and demonstrate such an approach this article documents initial coupon level thermoforming trials for a commercially available fibre reinforced thermoplastic laminate, identifying the key interactions between processing and whole life performance characteristics. To examine the role of the thermoforming process parameters on the whole life performance characteristics of the formed part requires a series of manufacturing trials combined with a series of characterisation tests on the manufacturing trial output. Using a full factorial test programme and considering all possible process parameters over a range of potential magnitudes would result in a very large number of manufacturing trials and accompanying characterisation tests. Such an approach would clearly be expensive and require significant time to complete, therefore failing to address the key requirement for a future design methodology capable of rapidly generating design knowledge for new materials and processes. In this work the role of mould tool temperature and blank forming temperature on the thermoforming of a commercially available thermoplastic based composite laminate is investigated followed by post processed part characterization. Key findings include an optimized composite processing window, and the influence of raw material blank forming temperature and mould tool temperature on part crystallinity and flexural strength. This process study forms one element of a major project structure which has been designed to address the gap between design, analysis and manufacturing, using at its core, a digital framework for the creation and management of performance parameters related to the lifecycle performance of thermoplastic composite structures.

2011-05-04

331

Thermoforming of Continuous Fibre Reinforced Thermoplastic Composites  

Science.gov (United States)

The introduction of new materials, particularly for aerospace products, is not a simple, quick or cheap task. New materials require extensive and expensive qualification and must meet challenging strength, stiffness, durability, manufacturing, inspection and maintenance requirements. Growth in industry acceptance for fibre reinforced thermoplastic composite systems requires the determination of whole life attributes including both part processing and processed part performance data. For thermoplastic composite materials the interactions between the processing parameters, in-service structural performance and end of life recyclability are potentially interrelated. Given the large number and range of parameters and the complexity of the potential relationships, understanding for whole life design must be developed in a systematic building block approach. To assess and demonstrate such an approach this article documents initial coupon level thermoforming trials for a commercially available fibre reinforced thermoplastic laminate, identifying the key interactions between processing and whole life performance characteristics. To examine the role of the thermoforming process parameters on the whole life performance characteristics of the formed part requires a series of manufacturing trials combined with a series of characterisation tests on the manufacturing trial output. Using a full factorial test programme and considering all possible process parameters over a range of potential magnitudes would result in a very large number of manufacturing trials and accompanying characterisation tests. Such an approach would clearly be expensive and require significant time to complete, therefore failing to address the key requirement for a future design methodology capable of rapidly generating design knowledge for new materials and processes. In this work the role of mould tool temperature and blank forming temperature on the thermoforming of a commercially available thermoplastic based composite laminate is investigated followed by post processed part characterization. Key findings include an optimized composite processing window, and the influence of raw material blank forming temperature and mould tool temperature on part crystallinity and flexural strength. This process study forms one element of a major project structure which has been designed to address the gap between design, analysis and manufacturing, using at its core, a digital framework for the creation and management of performance parameters related to the lifecycle performance of thermoplastic composite structures.

McCool, Raurí; Murphy, Adrian; Wilson, Ryan; Jiang, Zhenyu; Price, Mark

2011-05-01

332

Imprinting of confining sites for cell cultures on thermoplastic substrates  

Science.gov (United States)

Prevention of test cell migration beyond the field of observation involves confining cells or cultures in microlagoons made in either a layer of grease or a thermoplastic substrate. Thermoplastic films or dishes are easily imprinted with specifically designed patterns of microlagoons.

Cone, C. D.; Fleenor, E. N.

1969-01-01

333

Tough poly(arylene ether) thermoplastics as modifiers for bismaleimides  

Science.gov (United States)

Several aspects of research on thermoplastics as toughness modifiers are discussed, including the contribution of the backbone chemistry and the concentration of the poly(arylene ether) thermoplastic to fracture toughness, influence of the molecular weight of the poly(arylene ether) thermoplastic on neat resin fracture toughness, and the morphology of the thermoplastic modified networks. The results show that fracture toughness of brittle bismaleimide resins can be improved significantly with poly(arylene ether) thermoplastic levels of 20 percent by weight, and that high molecular weight poly(arylene ether) based on bisphenol A provides the highest degree of toughening. Preliminary composite evaluation shows that improvements in neat resin toughness translate into carbon fabric composite.

Stenzenberger, H. D.; Roemer, W.; Hergenrother, P. M.; Jensen, B. J.

1989-01-01

334

Thermoforming continuous fiber-reinforced thermoplastic composites  

Energy Technology Data Exchange (ETDEWEB)

In this research the forming process was first decomposed into basic deformation elements with simple geometries, and models were then developed for these elements. A series-parallel model was developed for predicting the upper and lower bounds of composite shear modulus at forming temperature based on the fiber content, fiber distribution, and matrix shear modulus. A shear-flexure model was proposed to describe the initial load-deflection behavior of thermoplastic composites in bending. A ply buckling model was developed which included the contributions from both a surface tension term and a ply buckling term.

Wu, Xiang.

1990-01-01

335

Trigeminal trophic syndrome treated with thermoplastic occlusion.  

Science.gov (United States)

A 72-year-old man with a history of thrombotic CVA causing lateral medullary infarction presented with non-healing ulcers of the right side of the face of 5 months' duration. After extensive investigations, a diagnosis of trigeminal trophic syndrome was made. The ulcers progressed relentlessly despite amitriptyline and gabapentin, and he was treated with a combination of carbamazepine and thermoplastic mask occlusion of the right side of his face. Over the next 10 weeks the shallower facial ulcers began to diminish in depth and diameter, and the deeper ulcers stopped progressing. Although the patient showed early signs of healing, he died because of complications from the CVA. PMID:21332680

Kurien, Anil M; Damian, Diona L; Moloney, Fergal J

2011-02-01

336

An afterloading brachytherapy device utilizing thermoplastic material  

International Nuclear Information System (INIS)

An afterloading brachytherapy device for treatment of residual cancer in an enucleated orbit with two cesium-137 sources was designed using a thermoplastic material, Aquaplast. The device consists of a face-mask support held in place with elastic bands around the head and an acrylic afterloading applicator. The device is very easy to make, holds the sources firmly in place, allows full mobility of the patient, and gives excellent dose distribution to the target area. It was easily tolerated by a 7-year-old child during the 50 h of treatment. (author). 3 refs.; 4 figs

1989-01-01

337

Radiation effects on carbon fiber reinforced thermoplastics  

International Nuclear Information System (INIS)

Polyether-ether-ketone (PEEK) and a newly developed thermoplastic polyimide ''new-TPI'' were applied to carbon fiber reinforced plastic (CFRP) as a matrix resin. PEEK and new-TPI showed excellent resistance over 50 MGy to electron irradiation and the crosslinking proceeded predominantly by irradiation. The changes in mechanical properties induced by electron irradiation of the CFRP with the two resins were examined at various temperatures. The flexural strength and modulus measured at -196 and 25 degree C were scarcely affected up to 120 MGy and both the values measured at high temperature were increased with dose

1993-02-15

338

Acetylation of rice straw for thermoplastic applications.  

Science.gov (United States)

An inexpensive and biodegradable thermoplastic was developed through acetylation of rice straw (RS) with acetic anhydride. Acetylation conditions were optimized. The structure and properties of acetylated RS were characterized by fourier transform infrared (FTIR), solid-state (13)C NMR spectroscopy, X-ray diffractometer (XRD), scanning electron microscope (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results showed that acetylation of RS has successfully taken place, and comparing with raw RS, the degree of crystallinity decreased and the decomposition rate was slow. The acetylated RS has got thermoplasticity when weight ratio of RS and acetic anhydride was 1:3, using sulphuric acid (9% to RS) as catalyst in glacial acetic acid 35°C for 12h, and the dosage of solvent was 9 times RS, in which weight percent gain (WPG) of the modified RS powder was 35.5% and its percent acetyl content was 36.1%. The acetylated RS could be formed into transparent thin films with different amount of plasticizer diethyl phthalate (DEP) using tape casting technology. PMID:23688473

Zhang, Guangzhi; Huang, Kai; Jiang, Xue; Huang, Dan; Yang, Yiqi

2013-07-01

339

Polyether Based Thermoplastic Polyurethane Melt Blown Nonwovens  

Directory of Open Access Journals (Sweden)

Full Text Available A series of melt blown samples were produced from three hardness grades of ether based thermoplastic polyurethane elastomers (TPU. The fabrics were tested to investigate their structure-property relationship in a melt blown process. Solution viscosities of the web were only 20-26% of there original values indicating a large loss in polymer molecular weight during melt blowing. Fiber diameter distributions measured on melt blown samples were found comparable to those made with more conventional polymers. The fiber orientation distribution functions (ODF suggest slight fiber orientation in machine direction. Tensile and elongation properties depended on die-to-collector distance (DCD, polymer hardness and fiber ODF. A strong relationship between the tensile strength and die-to-collector distance was identified and attributed to reduced interfiber adhesion in the web with increasing DCD. The reduction in adhesion was attributed to greater extents of solidification before reaching the forming belt for longer DCDs. This paper is the first in a series relating the influence of the melt blowing process parameters on the polymer properties and the nonwoven fabric properties for block thermoplastic elastomers.

Terezie Zapletalova

2006-08-01

340

Micromechanics of cyclic softening in thermoplastic vulcanizates  

Science.gov (United States)

The strain history dependence of the stress-strain behavior of thermoplastic vulcanizate (TPV) materials is studied through a set of experiments and micromechanical models. Thermoplastic vulcanizates are a class of composite material consisting of a high volume fraction of fully-cured elastomeric particles in a thermoplastic matrix. The stress-strain behavior of TPVs is found to soften after having been subjected to an initial load/unload cycle. In this paper, the TPV strain history dependence is experimentally documented on a representative TPV material (TPV-R) by subjecting TPV-R to load/unload/reload histories in plane strain compression to various magnitudes of strain. The stress-strain behavior is observed to be more compliant upon reloading, but the tangent modulus is found to increase with strain until the reloading stress-strain curve joins the initial curve. An increase in the magnitude of the initial strain excursion increases the compliance observed during reloading. The unloading behavior following the reload is very similar to the unloading behavior following the initial load. The underlying microscopic mechanisms which govern the strain history effects are investigated using micromechanical modelling of the composite structure and its deformation. The stress-strain behaviors predicted by the simulations are found to be in good agreement with the experimentally observed behavior over the entire strain history for each magnitude of strain considered. The models reveal the softening of the material to result from a reorganization of the particle/matrix microstructural configuration due to plastic stretching of interparticle ligaments during the initial load step followed by ligament bending and rotation during the unloading step. The new microstructural configuration that exists after the first load/unload cycle favors bending and rotation of the (now thinned) matrix ligaments (as opposed to plastic deformation of the ligaments) during reloading; the ligament bending and rotation occur under low stress levels which results in the more compliant response. The additional features of the stress-strain behavior during reloading are also captured well by the model.

Boyce, Mary C.; Yeh, Oscar; Socrate, Simona; Kear, Kenneth; Shaw, Karla

2001-06-01

 
 
 
 
341

Long-short fiber reinforced thermoplastics  

Energy Technology Data Exchange (ETDEWEB)

This paper presents information on a new family of fiber-reinforced thermoplastic compounds developed by ICI PLC and now produced by LNP under the trade mark ''Verton.'' Production is by a pultrusion process, rather than by the usual compounding extruder, which enables a high level of impregnation to be achieved without damaging the fibers. The result in molded parts is a 0.24-0.40 inch (6-10 mm) typical fiber length versus 0.008-0.016 inches (0.2-0.4 mm) for conventional short fiber products. Consequently, this enables fabricators to achieve typically a 10 to 20-fold increase in average fiber length in the finished component. These long-short fiber reinforced compounds exhibit substantial property improvements over short fiber system. Processing conditions are similar to corresponding short fiber compounds.

Gore, C.R.; Cuff, G.; Cianelli, D.A.; Travis, J.E.

1986-01-01

342

Thermoplastic starch films reinforced with talc nanoparticles.  

Science.gov (United States)

Nanocomposite films of thermoplastic corn starch (TPS) with talc particles were obtained by thermo-compression in order to study the effect of filler on structure, optical, and thermal properties. Talc increased the films rigid phase, thus their cross-sections resulted more irregular. Talc preferential orientation within matrix and good compatibility between particles and TPS was observed by SEM. Slight crystalline structure changes in TPS matrix were measured by XRD and DSC, due to talc nucleating effect. Randomly dispersed talc nanoagglomerates and individual platelets were assessed by TEM. Laminar morphology and nano-sized particles allowed that nanocomposite films were optically transparent. TPS-talc films resulted heterogeneous materials, presenting domains rich in glycerol and others rich in starch. Talc incorporation higher than 3%, w/w increased softening resistance of the nanocomposites as stated by DMA. Relaxation temperatures of glycerol-rich phase shifted to higher values since talc reduces the mobility of starch chains. PMID:23648028

Castillo, Luciana; López, Olivia; López, Cintia; Zaritzky, Noemí; García, M Alejandra; Barbosa, Silvia; Villar, Marcelo

2013-06-20

343

Thermoplastic polyimide NEW-TPI (trademark)  

Science.gov (United States)

Thermal and rheological properties of a commercial thermoplastic polyimide, NEW-TPI (trademark), were characterized. The as-received material possesses initially a transient crystallite form with a bimodal distribution in peak melting temperatures. After the melting of the initial crystallite structure, the sample can be recrystallized by various thermal treatments. A bimodal or single modal melting peak distribution is formed for annealing temperatures below or above 360 C, respectively. The recrystallized crystallinities are all transient in nature. The polymers are unable to be recrystallized after being subjected to elevated temperature annealing above 450 C. The recrystallization mechanism was postulated, and a simple kinetics model was found to describe the behavior rather satisfactory under the conditions of prolonged thermal annealing. Rheological measurements made in the linear viscoelastic range support the evidence observed in the thermal analysis. Furthermore, the measurements sustain the manufacturer's recommended processing window of 400 to 420 C for this material.

Hou, Tan-Hung; Reddy, Rakasi M.

1990-01-01

344

Characterization of thermoplastic polyimide NEW-TPI  

Science.gov (United States)

Thermal and rheological properties of a commercial thermoplastic polyimide, NEW-TPI, were characterized. The as-received material possesses initially a transient crystallite form with a bimodal distribution in peak melting temperatures. After the meltings of the initial crystallite structures, the sample can be recrystallized by various thermal treatments. A bimodal or single-modal melting peak distribution is formed for annealing temperatures below or above 360 C, respectively. The recrystallized crystallinities are all transient in nature. The polymers are unable to be recrystallized after being subjected to elevated temperature annealing above 450 C. The recrystallization mechanism was postulated, and a simple kinetics model was found to describe the behavior satisfactorily under conditions of prolonged thermal annealing.

Hou, T. H.; Reddy, R. M.

1991-01-01

345

Design and Analysis of Thermoplastic Composite Bridge Superstructures.  

Science.gov (United States)

This study is primarily focused on addressing the application of fiber reinforced composites (thermoplastics) in the design of bridge decks. Bridges are vital components of the nation's infrastructure, many of which are deteriorated. The replacement of su...

A. M. Abro N. Uddin U. Vaidya

2007-01-01

346

Laser assisted generation of electronic circuits on tailored thermoplastics  

Science.gov (United States)

This paper describes the tailoring of thermoplastics and the laser assisted generation of active regions that catalyze a chemical metal deposition in a liquid plating solution on these thermoplastics. The plated regions may serve as an electronic circuit on the insulating thermoplastic substrate. Tailoring of the thermoplastic materials is achieved by addition of a special activator powder. This powder consists of micro-encapsulated catalytic core particles with a non-catalytic barrier layer on their surface. Different encapsulation methods are compared for a copper core material. Laser activation is examined using a cw CO2 laser and an Nd:YAG laser. No activation is achieved with the CO2 laser. With the Nd:YAG laser and suitable process parameters, activation is possible even at writing speeds of up to 650 mm/s. A qualitative model is presented that explains the basic mechanisms of the laser activation process.

Esser, Gerd; Geiger, Manfred

2003-03-01

347

Solidification of radioactive wastes using thermoplastic resin  

International Nuclear Information System (INIS)

A new method has been developed by Niigata Engineering Company, Japan, of solidifying BWR wastes, i.e. evaporator concentrates, spent ion-exchange resins (granular and powder), and filtration sludges (cellulosic materials and diatomaceous earth), using thermoplastic resin as the fixing agent. Due to the fact that in Japan a suitable method for the final disposal of nuclear wastes has not yet been decided upon, at NEC we proposed and developed our own process. The method was developed with the following objectives in mind: (1) reduction of waste volume; and (2) effective immobilization of radionuclides. After close examination of the existing methods of waste treatment, i.e. solidification of wastes into monolithic block form with sea dumping as the means of the final disposal, and solidification of wastes into pellet form for interim storage until disposed of, after experiments a new method of binding wastes with thermoplastic resin was developed. Using this process only one system component is needed to produce both of the above-mentioned forms of solid waste. The process was tested by solidifying some wastes containing 60Co and 137Cs adsorbed by adding 60CoCl2 and 137CsCl solutions to waste slurries. The safety of the process and the behaviour of the radionuclides at each step of the process were closely checked. Subsequently the solidified products were tested and evaluated. Monolithic products were tested to determine such factors as density, uniformity, mechanical strength and leachability. Pellet form products were evaluated mainly with regard to maximization of volume reduction and mechanical strength; more than acceptable results were achieved in all cases. It is therefore concluded that this process can be used for the solidification of various wastes, and that it reduces waste volume. Also, this process is a safer and more efficient means of solidifying nuclear wastes than others offered by current technology. (author)

1982-06-21

348

Characterisation of IPNs of thermoplastic elastomers  

International Nuclear Information System (INIS)

Tough but strong composites can form using thermoplastic elastomers as starting materials by controlling nanometer-scale texture. Block copolymers based on butadiene or isoprene and styrene are widely used industrially. They can, when blended, toughen polystyrene but the formation of interpenetrating polymer networks (IPNs) is another potentially better way to enable compatibilization. IPNs combine two or more polymers in network form with one network polymerised and/or crosslinked in the immediate presence of the other. Materials can be formed with controlled morphologies, by for example growing the dispersed phase. Jones et al produced polystyrene/poly(styrene-butadiene-styrene) IPNs using thermal methods. Phase separation is confined to domains ? 20-40 nm and materials can have good mechanical and impact properties. Some samples however embrittled due to thermal degradation of the butadiene regions in the SBS material. It is possible to form similar IPNs of PS/SBS using gamma irradiation, which provides a room-temperature alternative to traditional thermal methods. However the previous work was confined to an oil-extended grade of SBS where the influence of the oil extension was not known. Here two main types of IPNs of block copolymers (thermoplastic elastomers, TPEs) and PS were prepared using sequential polymerisation. In one type, the TPE was thermally crosslinked, and styrene was polymerised and crosslinked using gamma irradiation to produce tough transparent IPNs which show no evidence of thermal degradation. A second group was prepared thermally, but with varying ratios of PS and TPE. These are of interest as the ratio affects strength and toughness. In this presentation we emphasise morphological aspects at the nm level using transmission electron microscopy and small angle neutron scattering

2003-08-17

349

Interlaminate Deformation in Thermoplastic Composite Laminates: Experimental-Numerical Correlation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The interlaminar deformation behaviors of thermoplastic AS4/PEEK composite laminates subjected to static tensile loading are investigated by means of microscopic moiré interferometry with high spatial resolution. The fully threedimensional orthotropic elastic-plastic analysis of interlaminar deformation for the thermoplastic laminates is developed in this paper, and used to simulate the stress-strain curves of tensile experiment for its angle-ply laminates. Under uniaxial tensile loadi...

2010-01-01

350

Characteristics and utilization of thermoplastic elastomers (TPE)-an overview  

Energy Technology Data Exchange (ETDEWEB)

The unique feature of thermoplastic elastomer, the combining of processing characteristics of thermoplastics with the physical properties of vulcanized rubber is reviewed. Highlights of TPE and its characteristics is aimed to generate interest in TPE, where SANS technique will be utilized for its characterization. The topics discussed include rubber elasticity, state of aggregation of polymers, microseparation in block copolymer system, application of TPE, and finally some notes in developing interest in TPE and SANS in Indonesia. (author)

Roestamsjah [R and D Center for Applied Chemistry, Indonesian Inst. of Sciences (Indonesia)

1998-10-01

351

Hybrid Joining of Aluminum to Thermoplastics with Friction Stir Welding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Hybrid structures including aluminum-thermoplastic and aluminum-reinforced thermoplastic composite are increasingly important in the near future innovations due to its lightweight and high strength-to-weight ratio. A critical point for metal-polymer application is that sound joining of these materials is difficult to achieve owing to a large difference in surface energy and dissimilar structure between metal and polymer. In practice, two major joining methods for hybrid structures are mechani...

2012-01-01

352

Study on resistance welding of glass fiber reinforced thermoplastic composites  

International Nuclear Information System (INIS)

Highlights: ? A Taguchi technique was used to design the experimental plan. ? TPC were joined by Resistance welding setup. ? TPC joints were characterized by mechanical and metallurgical study. ? Statistical method was used for parameter optimization of TPC joining. -- Abstract: Thermoplastic polymer industry has expanded a new impact with the introduction of Eco-friendly thermoplastic matrix composites (TPCs), which finds applications in medical, aerospace, electronic and automotive areas. Joints of non-conductive thermoplastic composite materials are processed by Resistance Welding (RW) by incorporating a conductive corrosion resistive conductive material, as an interlayer. Glass fiber reinforced polypropylene thermoplastic composite sheets were used for this study. The experimental set-up for resistance welding was fabricated. Welding current, clamping pressure and welding duration (Time) are the control parameters. The joining trials on composites were carried out using Taguchi method to reduce time and cost effective experimental studies. The effect of parameters which govern the quality of resistance welding of thermoplastic composites is also emphasized in this work. The purpose of this study is to determine the optimum process parameters for RW. The joints obtained were analyzed microscopically; it revealed the good integration of thermoplastic composite with the interlayer material. The mechanical strength of the joints is tested through lap shear strength testing.

2012-10-01

353

Novel polymer blends with thermoplastic starch  

Science.gov (United States)

A new class of polymers known as "bioplastics" has emerged and is expanding rapidly. This class consists of polymers that are either bio-based or biodegradable, or both. Among these, polysaccharides, namely starch, are of great interest for several reasons. By gelatinizing starch via plasticizers, it can be processed in the same way as thermoplastic polymers with conventional processing equipment. Hence, these bio-based and biodegradable plastics, with their low source and refinery costs, as well as relatively easy processability, have made them ideal candidates for incorporation into various current plastic products. Four different plasticizers have been chosen here for gelatinization of thermoplastic starch (TPS): glycerol, sorbitol, diglycerol and polyglycerol, with the latter two being used for the first time in such a process. Two methodological categories are used. The first involves a calorimetric method (Differential Scanning Calorimetry) as well as optical microscopy; these are "static" methods where no shear is applied A wide range of starch/water/plasticizer compositions were prepared to explore the gelatinization regime for each plasticizer. The onset and conclusion gelatinization temperatures for sorbitol and glycerol were found to be in the same vicinity, while diglycerol and polyglycerol showed significantly higher transition temperatures. The higher molecular weight and viscosity of polyglycerol allow this transition to occur at an even higher temperature than with diglycerol. This is due to the increase in molecular weight and viscosity of the two new plasticizers, as well as their significant decrease in water solubility. It is demonstrated that the water/plasticizer ratio has a pronounced effect on gelatinization temperatures. When plasticizer content was held constant and water content was increased, it was found that the gelatinization temperature decreased for all the plasticizers. Meanwhile, when the water content was held constant and the plasticizer content was increased, the gelatinization temperature increased for glycerol, sorbitol and diglycerol, but it moved in the opposite direction in the case of polyglycerol. The gelatinization temperature variation for glycerol, sorbitol and diglycerol caused by changing water and plasticizer content indicates that water is the primary agent causing granular swell and plasticization in the gelatinization process. Due to the high molecular weight and viscosity, as well as the low hydroxyl group density (~ one --OH per two carbon) and borderline solubility of polyglycerol in water, it is believed that water-aided penetration of the plasticizer among the crystalline structure of starch molecules is significantly decelerated. So it is proposed that in the case of low-water solubility of the plasticizers, gelatinization temperature is determined more by the total amount of the plasticizer and water, rather than the water/plasticizer ratio. Increasing the miscibility of polyglycerol in water by increasing the temperature of the initial slurry, results in a return of the system to the typical thermal dependence of gelatinization with plasticizer/water ratio. Secondly, the gelatinization of starch under "dynamic conditions" was studied. In this case, a constant shear is applied to the slurry, along with a temperature ramp to induce gelatinization. This is, in fact, a rheological technique that heats up the slurry, while a mechanical shear is applied throughout. The reason for using this method is that in the plastic industry, thermoplastic starch is produced via processes involving shear such as extrusion, but, to date, there has not yet been a thorough study on the effect of pure shear on the gelatinization process. Glycerol, diglycerol and sorbitol were subjected to different dynamic gelatinization treatments in a couette flow system, and the results were compared with static gelatinization. Applying shear showed virtually no effect on the onset gelatinization temperature. However, the conclusion temperature was remarkably reduced

Taghizadeh, Ata

354

Use of Melt Flow Rate Test in Reliability Study of Thermoplastic Encapsulation Materials in Photovoltaic Modules.  

Science.gov (United States)

Use of thermoplastic materials as encapsulants in photovoltaic (PV) modules presents a potential concern in terms of high temperature creep, which should be evaluated before thermoplastics are qualified for use in the field. Historically, the issue of cre...

G. Tamizhmani J. M. Moseley K. Sakurai M. D. Kempe Q. Shah S. R. Kurtz

2011-01-01

355

Improved adhesion for thermoplastic polymers using oxyfluorination  

International Nuclear Information System (INIS)

Industrial applications of thermoplastic polymers are often limited by their poor adhesion properties. In this work the effect of surface oxyfluorination on the adhesion properties was investigated for polyethylene (PE), polyoxymethylene (POM), polybutylene terephthalate (PBT) and polyamide 6 (PA6). The adhesive joint strength was quantified using lap-shear tests. These results were correlated with the changes in the chemical composition of the surface, determined by X-ray photoelectron spectroscopy (XPS), in the surface free energy, measured by the contact angle method, and in the topography, using white-light confocal microscopy. The adhesive strength is strongly improved for all four polymers, but the degree of this increase depends on the polymer type. The surface free energy shows a similar trend for all four polymers. A high surface free energy exceeding 50 mN/m was observed after oxy-fluorination, whereby the polar component was strongly predominant. Surface topography measurements show no significant increase of the surface roughness. So the effect of oxyfluorination results primarily in increased wettability and polarity, due to changes of the chemical composition of the surface. XPS measurements confirm the integration of fluorine and oxygen groups in the polymer chain, which correlates with the increased polarity

2008-03-01

356

Improved adhesion for thermoplastic polymers using oxyfluorination  

Science.gov (United States)

Industrial applications of thermoplastic polymers are often limited by their poor adhesion properties. In this work the effect of surface oxyfluorination on the adhesion properties was investigated for polyethylene (PE), polyoxymethylene (POM), polybutylene terephthalate (PBT) and polyamide 6 (PA6). The adhesive joint strength was quantified using lap-shear tests. These results were correlated with the changes in the chemical composition of the surface, determined by X-ray photoelectron spectroscopy (XPS), in the surface free energy, measured by the contact angle method, and in the topography, using white-light confocal microscopy. The adhesive strength is strongly improved for all four polymers, but the degree of this increase depends on the polymer type. The surface free energy shows a similar trend for all four polymers. A high surface free energy exceeding 50 mN/m was observed after oxy-fluorination, whereby the polar component was strongly predominant. Surface topography measurements show no significant increase of the surface roughness. So the effect of oxyfluorination results primarily in increased wettability and polarity, due to changes of the chemical composition of the surface. XPS measurements confirm the integration of fluorine and oxygen groups in the polymer chain, which correlates with the increased polarity.

Achereiner, F.; Münstedt, H.; Zeiler, T.

2008-03-01

357

Thermoplastic microcantilevers fabricated by nanoimprint lithography  

DEFF Research Database (Denmark)

Nanoimprint lithography has been exploited to fabricate micrometre-sized cantilevers in thermoplastic. This technique allows for very well defined microcantilevers and gives the possibility of embedding structures into the cantilever surface. The microcantilevers are fabricated in TOPAS and are up to 500 μm long, 100 μm wide, and 4.5 μm thick. Some of the cantilevers have built-in ripple surface structures with heights of 800 nm and pitches of 4 μm. The yield for the cantilever fabrication is 95% and the initial out-of-plane bending is below 10 μm. The stiffness of the cantilevers is measured by deflecting the cantilever with a well-characterized AFM probe. An average stiffness of 61.3 mN mâ??1 is found. Preliminary tests with water vapour indicate that the microcantilevers can be used directly for vapour sensing applications and illustrate the influence of surface structuring of the cantilevers.

Greve, Anders; Keller, Stephan Urs

2010-01-01

358

Recent innovations in reinforced thermoplastic pipe  

Energy Technology Data Exchange (ETDEWEB)

The use of reinforced thermoplastic pipe (RTP) can reduce the cost of pipeline construction and improve reliability. The technology combines high-performing materials with high-strength reinforcements to create a spoolable high pressure pipeline system that can be used in a variety of applications. This paper discussed a testing program conducted to determine the suitability of RTP for various applications in the oil and gas industry. Extensive tests were conducted to determine the pressure rating of RTP at 60 degrees C after and before exposure to solvents. Studies have also been conducted to investigate the effects of rapid depressurization of high pressure carbon dioxide (CO{sub 2}) gas on RTP. Tests were conducted to confirm the performance of RTP manufactured at higher temperatures. Experiments were also conducted to determine the use of glass fibers for reinforcement. Results of the study showed that the tested RTP is suitable for use in applications with aromatic hydrocarbons and other solvents up to a solvent concentration of 25 per cent for temperatures up to 20 degrees C, and a concentration of 5 per cent at 40 degrees C. Results also showed that the tested RTP is suitable for applications containing CO{sub 2} partial pressures up to 10.3 MPa. 1 tab., 5 figs.

Conley, J.; Weller, B.; Sakr, A. [Flexpipe Systems, Calgary, AB (Canada)

2010-07-01

359

Development of thermoplastic composite aircraft structures  

Science.gov (United States)

Efforts focused on the use of thermoplastic composite materials in the development of structural details associated with an advanced fighter fuselage section with applicability to transport design. In support of these designs, mechanics developments were conducted in two areas. First, a dissipative strain energy approach to material characterization and failure prediction, developed at the Naval Research Laboratory, was evaluated as a design/analysis tool. Second, a finite element formulation for thick composites was developed and incorporated into a lug analysis method which incorporates pin bending effects. Manufacturing concepts were developed for an upper fuel cell cover. A detailed trade study produced two promising concepts: fiber placement and single-step diaphragm forming. Based on the innovative design/manufacturing concepts for the fuselage section primary structure, elements were designed, fabricated, and structurally tested. These elements focused on key issues such as thick composite lugs and low cost forming of fastenerless, stiffener/moldine concepts. Manufacturing techniques included autoclave consolidation, single diaphragm consolidation (SDCC) and roll-forming.

Renieri, Michael P.; Burpo, Steven J.; Roundy, Lance M.; Todd, Stephanie A.; Kim, H. J.

1992-01-01

360

Transparency and phase structure in thermoplastic polyurethanes  

Energy Technology Data Exchange (ETDEWEB)

The relationship between transparency and phase structure in thermoplastic polyurethane (TPU) was studied. TPU used poly tetramethylene glycol (PTMG) has a very regular molecular structure, and is excellent in mechanical strength and chemical stability. However, TPU has higher-order structure which consists of hard and soft segments, and the phase separation tends to occur. Consequently, the transparency comes into question when it is used together with a transparent material or substituted for that. The phase separation and the morphology in TPU were examined through scanning electron microscopy, differential thermal analysis and X-ray diffraction varying various conditions. The size of hard segment governs the transparency of TPU. TPU becomes transparent by decreasing the size below 0.5 to 1.0{mu}m diameter. The micro-separated phase in TPU were attained under following conditions: decreasing PTMG molecular weight and hard content, using chain extender having side groups. The transparency was also attained through preparation under high mixing shear force due to making small the size of hard segment. 3 refs., 14 figs., 1 tab.

Kobayashi, Mitaka; Oguro, Kaoru; Kunii, Nobuaki; Nishimura, Hiromichi (Asahi Glass Co., Ltd., Tokyo, (Japan))

1989-07-25

 
 
 
 
361

Biodegradable thermoplastic polyurethanes incorporating polyhedral oligosilsesquioxane.  

Science.gov (United States)

A new hybrid thermoplastic polyurethane (TPU) system that incorporates an organic, biodegradable poly(D, L-lactide) soft block with a hard block bearing the inorganic polyhedral oligosilsesquioxane (POSS) moiety is introduced and studied. Changes in the polyol composition made through variation of the hydrophilic initiator molecular weight show direct control of the final transition temperatures. Incorporating POSS into the hard segments allows for excellent elasticity above T(g), as evidenced with dynamic mechanical analysis, not seen in most other biodegradable materials. This elasticity is attributed to physical cross-links formed in the hard block through POSS crystallization, as revealed with wide-angle X-ray diffraction. Increasing the POSS incorporation level in the TPU hard block was observed to increase crystallinity and also the rigidity of the material. The highest incorporation, using a statistical average of three POSS units per hard block, demonstrated one-way shape memory with excellent shape fixing capabilities. In vitro degradation of this sample was also investigated during a two month period. Moderate water uptake and dramatic molecular weight decrease were immediately observed although large mass loss (approximately 20 wt %) was not observed until the two month time point. PMID:18698847

Knight, Pamela T; Lee, Kyung Min; Qin, Haihu; Mather, Patrick T

2008-09-01

362

High-performance composite materials with thermoplastic matrix materials for air and space travel  

Energy Technology Data Exchange (ETDEWEB)

The development of new high-temperature thermoplastics has increased interest in the use of such materials in air and space travel. The most important characteristics that materials need to have to be used for these purposes are reviewed, and the processing of fiber-reinforced thermoplastics is described. Forming techniques applicable to such thermoplastics are briefly discussed, and the different kinds of semifabricated forms of fiber-reinforced thermoplastics are examined. 27 refs.

Brandt, J.; Richter, H.

1989-01-01

363

Wear comparison of thermoplastic materials used for orthodontic retainers.  

Science.gov (United States)

Clear thermoplastic retainers are an alternative to fixed lingual retainers and removable Hawley appliances. However, thermoplastic retainers have demonstrated poor wear resistance and durability after only a few months of use. In this study, a simulated wear device was used to compare the wear of different thermoplastic materials used for orthodontic retainers. Three thermoplastic products were evaluated: C+ (Raintree Essix, New Orleans, La),.040-in Invisacryl C (Great Lakes Orthodontics, Towanda, NY), and.040-in TR sheet material (Bay Dental Direct, Bay City, Mich). Twenty specimens were fabricated for each group. The specimens were vacuum thermoformed according to the manufacturers' recommendations and subjected to wear for 1000 cycles in a wear apparatus with steatite ceramic abraders. Depth of wear was determined by surface profilometry. The maximum peak-to-valley measurement was recorded for each specimen. Mean wear (SD) in microns was as follows: C+, 5.9 (2.4); Invisacryl C, 6.1 (2.6); and TR, 1.6 (0.9). One-way analysis of variance detected a significant difference between groups (P PETG), demonstrated greater resistance to wear than did the other 2 materials, which were softer, polypropylene-based thermoplastics. There was no evidence to suggest a difference in mean wear between the 2 polypropylene-based materials (P >.05). PMID:12970663

Gardner, Gary D; Dunn, William J; Taloumis, Louis

2003-09-01

364

Fabrication of thermoplastics chips through lamination based techniques.  

Science.gov (United States)

In this work, we propose a novel strategy for the fabrication of flexible thermoplastic microdevices entirely based on lamination processes. The same low-cost laminator apparatus can be used from master fabrication to microchannel sealing. This process is appropriate for rapid prototyping at laboratory scale, but it can also be easily upscaled to industrial manufacturing. For demonstration, we used here Cycloolefin Copolymer (COC), a thermoplastic polymer that is extensively used for microfluidic applications. COC is a thermoplastic polymer with good chemical resistance to common chemicals used in microfluidics such as acids, bases and most polar solvents. Its optical quality and mechanical resistance make this material suitable for a large range of applications in chemistry or biology. As an example, the electrokinetic separation of pollutants is proposed in the present study. PMID:22487893

Miserere, Sandrine; Mottet, Guillaume; Taniga, Velan; Descroix, Stephanie; Viovy, Jean-Louis; Malaquin, Laurent

2012-04-24

365

QCM Sensor Chip : – Construction of plastic parts for injection molding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

I augusti 2007 tillfrågades författaren av Attana AB om han kunde konstruera dennes QCM-sensorchip för formsprutning som en del av hans examensarbete inom industriell design. Examensarbetet innefattade de två plastdelarna som utgör hölget av sensorchipet. Ytterliggare skulle en ny konstruktionslösning som underlättar montering av sensorchipet föreslås, en given plats för identifikationsmärkning av sensorchipet skulle implementeras och den estetiska aspekten av designen skulle slut...

Fostock, Ziad

2009-01-01

366

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

367

Thermoplastic Explosive Compositions on the Base of Hexanitrohexaazaisowurtzitane  

Science.gov (United States)

Hexanitrohexaazaisowurtzitane is an azostructural compound known as CL-20. We performed a series of experiments with CL-20 synthesized in Russia to evaluate the possibility to use it in pressed high explosive compositions. We used it in thermoplastic compositions both with an inert binder and energetic binder. The compositions were conventionally named CL-20 Icy and CL-20A. It was determined that the thermoplastic compositions had the most high detonation parameters and a level of sensitivity to mechanical effects acceptable to allow their processing. Their detonation characteristics were compared with that of some known foreign compositions based on CL-20.

Ilyin, V. P.; Smirnov, S. P.; Kolganov, E. V.; Pechenev, Yu. G.

2006-08-01

368

LARC-TPI: A multi-purpose thermoplastic polyimide  

Science.gov (United States)

A linear thermoplastic polyimide, LARC-TPI, was characterized and developed for a variety of high temperature applications. In its fully imidized form, this material can be used as an adhesive for bonding metals such as titanium, aluminum, copper, brass, and stainless steel. LARC-TPI was evaluated as a thermoplastic for bonding large pieces of polyimide film to produce flexible, 100 void-free laminates for flexible circuit applications. The development of LARC-TPI as a potential molding powder, composite matrix resin, high temperature film and fiber is also discussed.

St.clair, A. K.; St.clair, T. L.

1982-01-01

369

On-line consolidation of thermoplastic composites  

Science.gov (United States)

An on-line consolidation system, which includes a computer-controlled filament winding machine and a consolidation head assembly, has been designed and constructed to fabricate composite parts from thermoplastic towpregs. A statistical approach was used to determine the significant processing parameters and their effect on the mechanical and physical properties of composite cylinders fabricated by on-line consolidation. A central composite experimental design was used to select the processing conditions for manufacturing the composite cylinders. The thickness, density, void content, degree of crystallinity and interlaminar shear strength (ILSS) were measured for each composite cylinder. Micrographs showed that complete intimate contact and uniform fiber-matrix distribution were achieved. The degree of crystallinity of the cylinders was found to be in the range of 25-30%. Under optimum processing conditions, an ILSS of 58 MPa and a void content of slip ring assembly and a computer data acquisition system was developed to obtain temperature data during winding. Composite cylinders were manufactured with eight K-type thermocouples installed in various locations inside the cylinder. The temperature distribution inside the composite cylinder during winding was measured for different processing conditions. ABAQUS finite element models of the different processes that occur during on-line consolidation were constructed. The first model was used to determine the convective heat transfer coefficient for the hot-air heat source. A convective heat transfer coefficient of 260 w/msp{2°}K was obtained by matching the calculated temperature history to the in-situ measurement data. To predict temperature distribution during winding an ABAQUS winding simulation model was developed. The winding speed was modeled by incrementally moving the convective boundary conditions around the outer surface of the composite cylinder. A towpreg heating model was constructed to predict the temperature distribution on the cross section of the incoming towpreg. For the process-induced thermal stresses analysis, a thermoelastic finite element model was constructed. Using the temperature history obtained from thermal analysis as the initial conditions, the thermal stresses during winding and cooling were investigated.

Shih, Po-Jen

370

Thermoplastic polyurethane (TPU)/polyolefin (PO) blends  

Science.gov (United States)

Thermoplastic polyurethane (TPU) is a very important material with high versatility and superior physical properties. Melt blending TPU with metallocene polyolefin (PO) can lower TPU cost and improve polyolefin properties like abrasion resistance, adhesion, and paintability. Since TPU and non-polar PO blends are completely immiscible, efficient compatibilizers become the key issue and remain challenging. My main thesis work is to develop and study compatibilized TPU/PO blends. Although reactive compatibilization is considered the most efficient method, fast interfacial reactions between highly reactive functional groups are necessary to generate compatibilizers within usually short processing time. It is known that the urethane linkage (carbamate -NHCOO-) in TPU can reversibly dissociate to generate highly reactive isocyanates at melt temperatures. To find out the best reactive compatibilization, three approaches were employed on different molecular scales: (1) model urethane compound (dibutyl & dioctyl 4,4'-methylenebis(phenyl carbamate)) and small functional molecule (primary amine, secondary amine, hydroxyl, acid, anhydride, and epoxide) reactions at 200°C monitored by nuclear magnetic resonance and Fourier-transform infrared to examine the basic chemistry; (2) short, model TPU's with different chemical structures blended with functional polymers including poly(ethylene glycol) and polybutadiene to explore the effect of interface in immiscible mixtures; (3) melt blending of a commercial TPU with polypropylene (PP), further involving more complicated morphology, using different types of functional PP's (note: amine functional PP's were prepared by melt amination) as compatibilizers followed by rheological, morphological, thermal, and mechanical characterizations. Besides the core thesis project on TPU blends, other related work that has been accomplished includes: (1) adhesion between TPU and PP; (2) rheological properties of TPU; (3) block copolymer formation by reactive coupling. In the first work, the unique interfacial reactions were applied to promote TPU-PP adhesion that was quantified by asymmetric double cantilever beam test. In the second study, the abnormally high flow activation energy of TPU was explained by simultaneously investigating the effect of temperature and thermal degradation on the melt viscosity. In the third project, block copolymers were prepared by rapid reactive coupling of amine and isocyanate functional polymers and the reaction kinetics were also studied.

Lu, Qiwei

371

Consolidation mechanisms and interfacial phenomena in thermoplastic powder impregnated composites  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermoplastic powder impregnation of continuous reinforcement filaments is studied in this work, focusing on impregnation mechanisms and interfacial phenomena. Various existing techniques to mingle powdered resins to continuous filaments are reviewed; a powder impregnation line designed at the Laboratoire de Technologie des Composites et Polymères (LTC) is presented. Two important types of powder coated towpregs are addressed: FIT bundles (Fibr...

Connor, Marco Tom

1995-01-01

372

Antimicrobial thermoplastic materials for biomedical applications prepared by melt processing  

Science.gov (United States)

In this work thermoplastic polymers with antimicrobial properties were prepared by incorporating an antibiotic, i.e., ciprofloxacin (CFX), by melt processing. Two different polymers were used as matrices, i.e., polypropylene (PP) and poly(lactid acid) (PLA) and different concentrations of CFX have been incorporated. The antimicrobial properties, the release kinetic and the mechanical performances of the prepared materials were evaluated.

Botta, L.; Scaffaro, R.; Ceraulo, M.; Gallo, G.

2014-05-01

373

Advanced thermoplastic materials for district heating piping systems  

Energy Technology Data Exchange (ETDEWEB)

The work described in this report represents research conducted in the first year of a three-year program to assess, characterize, and design thermoplastic piping for use in elevated-temperature district heating (DH) systems. The present report describes the results of a program to assess the potential usefulness of advanced thermoplastics as piping materials for use in DH systems. This includes the review of design rules for thermoplastic materials used as pipes, a survey of candidate materials and available mechanical properties data, and mechanical properties testing to obtain baseline data on a candidate thermoplastic material extruded as pipe. The candidate material studied in this phase of the research was a polyetherimide resin, Ultem 1000, which has a UL continuous service temperature rating of 338/degree/F (170/degree/C). The results of experiments to determine the mechanical properties between 68 and 350/degree/F (20 and 177/degree/C) were used to establish preliminary design values for this material. Because these prototypic pipes were extruded under less than optimal conditions, the mechanical properties obtained are inferior to those expected from typical production pipes. Nevertheless, the present material in the form of 2-in. SDR 11 pipe (2.375-in. O. D. by 0.216-in. wall) would have a saturated water design pressure rating of /approximately/34 psig at 280/degree/F. 16 refs., 6 figs., 8 tabs.

Raske, D.T.; Karvelas, D.E.

1988-04-01

374

Dielectric Characterization of PCL-Based Thermoplastic Materials for Microwave Diagnostic and Therapeutic Applications  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We propose the use of a polycaprolactone (PCL)-based thermoplastic mesh as a tissue-immobilization interface for microwave imaging and microwave hyperthermia treatment. An investigation of the dielectric properties of two PCL-based thermoplastic materials in the frequency range of 0.5 – 3.5 GHz is presented. The frequency-dependent dielectric constant and effective conductivity of the PCL-based thermoplastics are characterized using measurements of microstrip transmission lines fabricated o...

Aguilar, Suzette M.; Shea, Jacob D.; Al-joumayly, Mudar A.; Veen, Barry D.; Behdad, Nader; Hagness, Susan C.

2012-01-01

375

Micro hot embossing of thermoplastic polymers: a review  

Science.gov (United States)

Micro hot embossing of thermoplastic polymers is a promising process to fabricate high precision and high quality features in micro/nano scale. This technology has experienced more than 40 years development and has been partially applied in industrial production. Three modes of micro hot embossing including plate-to-plate, roll-to-plate and roll-to-roll have been successively developed to meet the increasing demand for large-area patterned polymeric films. This review surveys recent progress of micro hot embossing in terms of polymeric material behavior, embossing process and corresponding apparatus. Besides, challenges and innovations in mold fabrication techniques are comprehensively summarized and industrial applications are systematically cataloged as well. Finally, technical challenges and future trends are presented for micro hot embossing of thermoplastic polymers.

Peng, Linfa; Deng, Yujun; Yi, Peiyun; Lai, Xinmin

2014-01-01

376

Processability of Pultrusion Using Natural Fiber and Thermoplastic Matrix  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fundamental mechanisms of the pultrusion process using commingled yarns of polypropylene matrix and discontinuous flax fiber to produce thermoplastic profiles were investigated in numerical and experimental manners. Essential issue is the fact that all natural fibers are discontinuous by nature, which may negatively influence the processability. The pultrusion process will be only successful if the pulling force exerted on the solidified pultrudates can be transmitted to the regions of unmelt...

Tham Nguyen-Chung; Klaus Friedrich; Nter Mennig, G.