• Design & Manufacturing
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• v.15 no.2
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• pp.36-41
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• 2021

The 3 dimensional Pipe (Annular) Shaped Products was selected as a test sample, then a attribute of a molding shrinkage according to the parameters of a injection process was examined with PC, which is the typical engineering plastic. Both the inside and the outside diameter of the Pipe (Annular) sample were shrank into the inner direction of the part. And then the comparative analysis of the samples proved that a increasing thickness led a bigger shrinkage rate in the equal outside diametric samples, and a decreasing outside diameter caused a bigger shrinkage rate in the same thickness samples. The comparative study of the cushion volume of a injection machine showed that the molding shrinkage was most affected by the pressure strength among the resin temperature, the maintenance pressure strength and the maintenance pressure duration time. Each of the shrinkage rates according to the measuring direction and the gate position was different. As a result, the injection molded sample had not a typical circular shape.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.5
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• pp.659-665
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• 2011

Recently, the plastic resin such as PC, ABS are widely used in IT market. Especially, in most cases the keypads mounted on the mobile phone are the dual-injection-plated type. Environmental regulation is based on the quality of injection-molded products and the minimum process steps are required to avoid the plating defects. Various parameters to produce the injection-molded plastic products make it difficult to obtain the desired stability. However, the past experience and the use of CAE analysis make it possible to predict the problems occurred in injection molding process. Especially, the problems of the weld lines such as runner balancing, bending, deformation and forming defects can be solved systematically and minimized by CAE analysis. Through this study, the non-uniform volumetric shrinkage and the difference in temperature distribution induce the deformation and the high value of stress causes the problems such as crack.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.97-100
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• 1997

In order to predict the moldability of a injection molded part, a simulation of filling is needed. Especially when short shot is predicted by CAE simulation in the filling stage, there are mainly three ways to solve the problem. Modification of gate and runner, replacement of plastic resin, and adjustment of process conditions are the main ways. Among them, adjustment of process conditions is the most economic way in the cost and time since the mold doesn\\`t need t be modified at all. But it is difficult to adjust the process conditions appropriately in no times since it requires an empirical knowledge of injection molding. In this paper, a fuzzy neural network(FNN) based upon injection molding process is proposed to evaluate moldability in filling stage and also to solve the problem in case of short shot. An adequate mold temperature is generated through the fuzzy neural network where fill time and melt temperature are taken into considerations because process conditions affect each other.

• Design & Manufacturing
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• v.2 no.5
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• pp.11-15
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• 2008

A micro-injection mold for ultra-thin-walled plate was considered in this work. The proposed mold system is for the fabrication of ultra-thin walled plastic plate with micro features by injection molding. As the injection molding of thin-walled plastic, which has the thickness under $400{\mu}m$, itself is not easy, the injection molding of the micro-features in the thin-walled structure is more complicated and difficult. To investigate the basic phenomenon of the ultra-thin walled part during the injection molding process, design of the part and mold system were performed in the present study. The injection molding and structural analysis of the suggested part and mold system were also performed. Consequently, injection molding system for ultra-thin walled plate with micro features were manufactured and presented.

• Transactions of Materials Processing
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• v.17 no.8
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• pp.662-667
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• 2008

Because of steep rise of international energy cost in recent years, high efficiency has been emphasized in energy policy. As far as injection molding machine is concerned, hybrid method using hydraulic and electric systems became the key to this energy saving. The energy saving and molding reproducibility of hybrid injection molding process were shown experimentally. The power consumption of hybrid injection molding machine is reduced to 38% as compared with that of hydraulic machine. Furthermore, the molding reproducibility was shown for both methods.

• Design & Manufacturing
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• v.13 no.2
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• pp.30-36
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• 2019

Traditional cell culture(2-dimensional) is the method that provide a nutrient and environment on a flat surface to cultivate cells into a single layer. Since the cell characteristics of 2D culture method is different from the characteristics of the cells cultured in the body, attempts to cultivate the cells in an environment similar to the body environment are actively proceeding in the industry, academy, and research institutes. In this study, we will develop a technology to fabricate micro-structures capable of culturing cells on surfaces with various curvatures, surface shapes, and characteristics. In order to fabricate the hemispheric plastic structure(thickness $50{\mu}m$), plastic preform mold (hereinafter as "preform mold") corresponding to the hemisphere was first prepared by injection molding in order to fabricate a two - layer structure to be combined with a flat plastic film. Then, thermoplastic polymer dissolved in an organic solvent was solidified on a preform mold. As a preliminary study, we proposed injection molding conditions that can minimize X/Y/Z axis deflection value. The effects of the following conditions on the preform mold were analyzed through injection molding CAE, [(1) coolant inlet temperature, (2) injection time, (3) packing pressure, (4) volume-pressure (V/P). As a result, the injection molding process conditions (cooling water inlet temperature, injection time, holding pressure condition (V / P conversion point and holding pressure size)) which can minimize the deformation amount of the preform mold were derived through CAE without applying the experimental design method. Also, the derived injection molding process conditions were applied during actual injection molding and the degree of deformation of the formed preform mold was compared with the analysis results. It is expected that plastic film having various shapes in addition to hemispherical shape using the preform mold produced through this study will be useful for the molding preform molding technology and cast molding technology.

• 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.

• 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