• 소성∙가공
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• 제20권1호
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• pp.11-16
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• 2011

Recently, according to the rapid development of display, many display applications, such as, cellular phone, navigation, monitor and LCD TV have been changed from CRT type to LCD type. BLU(Back Light Unit) is one of main parts in LCD unit and generally, it consists of a light source, a reflective sheet, a LGP(Light Guide Plate), a diffuser sheet, and two prism sheets. The most important component of BLU is a light guide plate, which diffuses the input light to the TFT-LCD module uniformly. The LGP is usually made by injection molding process, and it has numerous optical micro patterns on the surface. In the present study the micro-patterned stamper which has cylindrical shape was fabricated by using the UV-LiGA process. And the replication characteristics have been compared among three different kinds of injection molding process; general injection molding, injection/compression molding and RHCM(Rapid Heating and Cooling Molding). Average replication ratios of CIM and ICM were 19.1% and 64.6%, respectively. On the other hand, the average replication ratio of RHCM process showed the higher value of 98.4% among these. It show that maintaining the mold surface above $T_g$ could increase the replication ratio of micro patterns substantially.

• Design & Manufacturing
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• 제13권2호
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• pp.1-5
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• 2019

In this study, micro cellular injection molding of automobile head lamp housing with uneven thickness structure was performed to obtain improvement on deformation and light-weight of the part. The thickness of the presented model was uniformly modified to control the deformation of the molded part. In order to maximize the lightweight ratio, the model having an average thickness of 2.0 mm were thinly molded to an average thickness of 1.6 mm. GFM(Gas Free Molding) and CBM(Core Back Molding) technology were applied to improve the problems of the conventional foam molding method. Equal Heat & Cool system was also applied by 3D cooling core and individual flow control system. Warpage of the molded parts with even cooling was minimized. To improve the mechanical properties of foamed products, complex resin containing nano-filler was used and variation of mechanical properties was evaluated. It was shown that the weight reduction ratio of products with light-weighted injection molding was 8.9 % and the deformation of the products was improved from the maximum of 3.6 mm to 2.0 mm by applying Equal Heat & Cool mold cooling system. Also the mechanical strength reduction of foamed product was less than 12% at maximum.

• 한국표면공학회지
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• 제51권1호
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• pp.40-46
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• 2018

The light-weight of the research and development materials is actively carried out by overseas automobile companies and technology development continues in Korea. For the sake of fuel efficiency, the development of lightweight technology by improving the manufacturing method has been very effective. Recently, to maximize the effects of light weight, automotive interior parts have been applied by the micro-cellular injection molding using supercritical fluids and we call the Mucell manufacturing. This technique causes a problem in the quality of the surface of the products, because the shooting cells are revealed as the surface layer of the products by forming micro cells at the center of the products during injection molding. To overcome these phenomenon, we increased the temperature of injection molding using joule heating until critical value. In this study, we have predicted the problem of Mucell injection molding through the finite element analysis as changed the temperature by joule heating. From the result of finite element analysis, we have determined the optimized process and made the injection mold included electric current heating system with Mucell manufacturing analyzed the surface characteristics of the injection product according to changing mold temperature.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.263-268
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• 2001

MCPs means Micro Cellular Plastics. The micro-cells are generated in the products by the difference of dissolution through the pressure drop after super critical fluid of CO2 or N2 dissolves into polymer. We have developed injection molding process adopting MCPs and applied it to a broad range of injection molded thermoplastic materials and applications. It can prevent the leakage of impact strength and increase the thermal conductivity, moreover regulate the thermal conductivity. Then we can develop the high strength foaming plastics. Also, it can be gained a competitive advantage by utilizing its processing benefits, e.g. the lightweight products and significant reductions in material consumption.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.1046-1050
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• 2005

Micro Cellular Plastics create a sensation at polymer industrial for lowering product cost & overcoming a lowering of mechanical intensity. There Is much development from injection molding pans but Extrusion parts is slow. This research is MCPs Extrusion parts, It is basis experiment for Process to make beads that is basis raw material of Package used most by shock mitigative of industry.

• 한국정밀공학회지
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• 제17권9호
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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.