• Design & Manufacturing
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• v.2 no.6
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• pp.7-10
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• 2008

Injection-stretch blowing system for preform has been developed in this study. The preforms for injection blow molding and injection stretch blow molding are being manufactured by injection molding. However it contains gate mark that affects the bottom crack in the PET bottle. The compression molded preform does not contain gate mark, thus the appearance quality of bottle has been increased and the residual stress near gate(bottom of the bottle) has been reduced. The thickness distributions, haze, and transmittance are well accepted for the preform. Also, flow characteristics of the resin between a core and cavity could be analyzed through computer simulation.

• Journal of the Korean Society of Industry Convergence
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• v.10 no.4
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• pp.285-289
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• 2007

This study presents the preform injection molding of the injection stretch-blow molding process for PET bottles. The numerical analysis of the injection molding of a preform is considered in this paper using CAE with a view to minimize the warpage. In order to determine the design parameters and processing conditions in injection molding, it is very important to establish the numerical model with physical phenomenon. In this study, a three dimensional model has been introduced for the purpose and flow simulations of filling, post-filling and cooling process are carried out. The simulations resulted in the warpage in good agreement with the measurements. Also, from the result of numerical analysis, we appropriate -ly predicted the warpage, deformation and thickness distribution along the preform wall.

• Transactions of Materials Processing
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• v.21 no.2
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• pp.107-112
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• 2012

Gas-assisted injection molding(GAIM) produces parts with hollow internal sections. The technique offers benefits to powder injection molding(PIM), with lower material usage and reduced time for de-binding processes. In this study, the effects of processing parameters on gas penetration length of gas-assisted powder injection molding(GAPIM) were investigated for SUS316L stainless steel powder feedstock. Experiments were planned based on the Taguchi method, involving processing variables such as melt temperature, shot size, gas pressure, and gas delay time. The most significant parameters affecting gas penetration length were gas delay time and shot size, while the effects of melt temperature and gas pressure was relatively insignificant.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.6
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• pp.64-70
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• 1999

Family injection molding of plastic is widely used to enhance productivity. Runners for molded products in fami-ly injection molding have to be balanced so that each of the producs is filled completely at the same time,. In this study computer simulations were performed to determine balanced circular section runners in family injection molding with two cavities where each of he cavity shapes is like a case. It was found from the computer simula-tions that runner balance could be fulfilled only by modifying runner diameters. But in order to get more quality molded products other process factors such as flow length flow resistance shapes of products and etc, should be taken in to consideration for the design of a family injection molding process.

• Journal of Powder Materials
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• v.9 no.4
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• pp.245-250
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• 2002

In this paper we presented numerical method for the simulation of powder injection molding filling process, which is one of the key processes in powder injection molding. Rheological properties of powder binder mixture such as slip phenomena and yield stress were introduced into the numerical analysis model of powder injection molding filling simulation. Numerical model can be classified into two types. One is 2.5D model which can be introduced to a arbitrary thin geometry and the other is full 3D model which can be applied to a general 3D shape. For 2.5D model we showed the validity of our CAE system with several verification examples. Finally we suggested flow analysis model for 3D powder injection molding filling simulation.

• Transactions of Materials Processing
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• v.14 no.6 s.78
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• pp.491-495
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• 2005

Micro injection molding analysis for microneedle fabrication was performed in the present study. The dimensions of width and thickness for in-plane microneedle are $600{\mu}m$, $500{\mu}m$, respectively. A delivery system based on guidelines for traditional injection molding was designed for four-cavities molding system. To investigate the effects of processing conditions in the mirconeedle fabrication, injection molding analysis using commercial code was performed. It was shown that the total injection time has a significant effect on the fabrication of in-plane microneedles.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.55-59
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• 2005

Micro injection molding analysis for microneedle fabrication was performed in the present study. The dimensions of width and thickness for microneedle are 600um, 500um, respectively. A delivery system based on guidelines for traditional injection molding was designed for four-cavities molding system. To investigate the effects of processing conditions in the mirconeedle fabrication, injection molding analysis using commercial code was performed. It was shown that the total injection time has a significant effect on the fabrication of microneedles.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.436-441
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• 2005

In this study, precision injection molding analysis for BGA connector fabrication was performed. A BGA connector model with rectangular micro-holes were introduced to investigate the effect of mirco patterns on the injection molding process. Dual domain(2.5D) mesh and full 3D mesh for BGA connector model were prepared to perform precision injection molding analysis. To verify the Present analysis, experiments of injection molding were performed based on the results of the analysis. It was shown that the type of mesh has a significant effect on the flow pattern of BGA connector

• Advanced Composite Materials
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• v.16 no.3
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• pp.207-221
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• 2007

The filling process of resin injection/compression molding (I/CM) can be divided into injection and compression phases. During the resin injection the mold is kept only partially closed and thus a gap is present between the reinforcements and the upper mold. The gap results in preferential flow path. After the gap is filled with the resin, the compression action initiates and forces the resin to penetrate into the fiber preform. In the present study, the resin flow in the gap is simplified by using the Stokes approximation, while Darcy's law is used to calculate the flow field in the fiber mats. Results show that most of the injected resins enter into the gap during the injection phase. The resin injection time is extremely short so the duration of the filling process is determined by the final closing action of the mold cavity. Compared with resin transfer molding (RTM), I/CM process can reduce the mold filling time or injection pressure significantly.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.375-376
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• 2006

Thermoplastic elastomer(TPE) can be molded by conventional injection molding. Therefore TPE injection molding could be analyzed by commercial flow analysis software. However there are a little of gaps on CAE simulation results and practical molding. In this study, the properties of TPE were measured and applied to CAE simulation for comparing the simulation flow pattern and real flow pattern. The pattern that was controlled by injection time was match. The pattern that was controlled by injection stroke and rate was not match.