• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.341-345
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• 2001

New technoloty called microcellular foaming process was developed at MIT in 1980's. Although it has many good things, it could not be used it all sides of manufacturing plastics. Because it takes a long time for making foamed goods. So microcellular foaming injection molding process appeared to solve this problem. The first purpose of this research is to measure the impact strength as foaming magnitude of microcellular foamed plastics. There are two methods such as batch process and microcellular foaming injection molding process in making foamed plastics. According to the experimental data, the impact strength of each specimen was measured to find out the influence of foaming magnitude of microcellular foamed plastics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1354-1357
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• 2003

Mold Analysis is crucial factors in the design of injection molding process. Since the qualify of products depends on filing, shrinkage and etc, the procedure of prediction through analysis in the design of injection molding process is needed. In many cases, this kind of analysis makes it possible to predict pressure pattern which determines the condition of injection molding process. Crystallinity is the factor that determines the shrinkage of products. The studies showed the factors that had been related to the degree of crystallinity, which were mostly Weight Reduction, mold temperature and melt temperature. Therefore, the objective of this study is to see the differences of the degree of crystallinity depending on the positions of foamed plastics. The procedure of this study is as the following. First, Simulate the pressure gradient in mold cavity that can produces specimen by using Moldflow. Secondly, produce specimen and measure the degree or crystallinity of each part of specimen by using XRD. Lastly, identify the sensitivity of conventional plastic and foamed plastic on pressure gradient by comparing the simulation and the results of measurement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.71-72
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.827-828
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• 2008

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.991-996
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• 2004

Plastics are widely used in industry, because they are light, easily manufactured, and have high specific strength. And many researches to increase the strengths and to reduce the price are being conducted at now. One of these researches is concerning to additives. Foaming techniques are used to endow insulation properties, to improve specific strength, or reduce the material cost. Due to their unique properties, foamed plastics are applied to refrigerator, pipe, and insulators. Micro-cellular foaming is the latest foaming technique that was invented at 1980 in MIT. It is known that many tiny small cells are generated in the polymer matrices and micro-cellular foamed plastics show relatively high specific strength. We investigated the role of CaCO3 which is one of the most widely used additives in plastics industry as an additive for nucleation in view of cell morphology. CaCO3 used in this paper was treated to increase the dispersibility and to lower the density, so it has many pores at his body. Two experiments were conducted, in order to check the role of an additive for nucleation. One is compound-ability and the other one is role of nucleation agents.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.335-340
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• 2001

We use so many plastic products in everyday. Because polymer materials have a lot of merits including low cost and easiness of forming, they are widely used in many manufacturing industries. Microcellular foaming process was developed at MIT in 1980's to save a quantity of materials and increase mechanical properties. The improvement of strength is very important factor in relation with the reduction of mass. So the first purpose of this research is to improve the strength of the microcellular foamed plastics as variation of glass-fiber's volume friction. Also the characteristic of filler such as glass-fiber was presented in a microcellular foaming process.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.1
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• pp.195-200
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• 2001

There is a great demand for reducing the amount of material used in mass-produced plastics parts, for material cost constitutes up to 75% of the total production cost. Plastics do not easily decay which causes environmental problem. Furthermore, material reduction therefore decreases the amount of oil needed for the manufacture of plastics and thus help conserve this natural resource. Therefore, microcellular foamed plastics(MCPs) was developed at MIT to solve these problem alternation 1980's. Until now, however, microcellular foaming process not designed systematically because the key factors governing the process were not clear. The goal of this research is to obtain the optimal design of the microcellular plastics by using axiomatic approach.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.9
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• pp.196-201
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• 2000

There is a great demand for reducing the amount of material used in mass-produced plastics parts for material cost constitutes a large percentage of the total cost of a product up to 75% It may be noted that the price of plastics is directly related to the price of petroleum. Material reduction therefore decreases the amount of oil needed for the manufacture of plastics and thus help conserve this natural resource. Therefore microcellular foaming process(MCPs) was studied for solving this problems alternatively in 1980's at M. I. T. Until now in microcellular plastics processes carbon dioxide gas was mainly used for microcellular foaming Because carbon dioxide has more solubility than any other gases such as nitrogen gas or helium gas. The purpose of the this research is measurement of changing of the microcellular plastics' weight by using nitrogen gas in injection molding an comparing weight reduction of microcellular foamed plastics for using carbon dioxide gas with nitrogen gas.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.725-726
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1187-1188
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• 2010