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홍명표,김우성,성지현,김동혁,배기만,김영석 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.5 No.1
The manufacturing industry nowadays has a greater interest in reducing global warming and promoting energy-saving measures than ever before. This has led to the development of eco-friendly manufacturing systems to replace conventional ones. Additive manufacturing (AM) technology, for instance, is expected to contribute to reducing material costs and energy consumption. Unlike conventional material-cutting manufacturing processes, AM enables designs of any shape in manufacturing by adding the necessary parts layer by layer. Direct energy deposition (DED) is one of the many AM technologies available for a variety of commercial steel powders such as P20, P21, SUS420, H13, D2 and other Non-ferrous metal powders. The DED is process that can be applied to various industries, like molding, medicine, and defense. Of these, its application to the molding industry is the most practical, since the process can be used to deposit different materials on existing parts. Using this technology, it becomes possible to manufacture high-functioning parts composed of various materials at reasonable cost. In this study, the DED is used to develop a high-performance and environmentally friendly trimming die. In this study, to develop a high performance and environmentally friendly trimming die using DED, evaluation of mechanical properties of material developed, stress analysis in shear work. The commercialization of the developed technology was evaluated and the commercial application of the developed technology was discussed.
저분자량 디올이 체인 연장제로서 HTPB 우레탄 탄성 중합체의 기계적 성질에 미치는 영향
홍명표,노만균,김용준,Myong Pyo Hong,Man Gyoon No,Yong Joon Kim 대한화학회 1983 대한화학회지 Vol.27 No.1
체인 연장체로서 저분자량 디올의 5종(에틸렌글리콜, 1,3-프로판디올, 1,4-부탄디올, 1,5펜탄디올, 1,6-헥산디올)과 경화제로서 TDI 및 IPDI를 사용하여 HTPB 우레탄 탄성 중합체를 제조하였다. 저분자량 디올의 농도, 저분자량 디올의 메틸렌기의 수, 벤젠고리를 소유한 TDI와 시클로헥산을 소유한 IPDI의 영향에 따른 기계적 성질(인장강도, 100% 탄성계수, 경도)의 변화를 고찰한 결과 저분자량 디올의 농도가 증가할수록 우페탄 농도의 영향으로 기계적 성질이 예상한 바와 같이 증가하였다. 경화제로서 IPDI를 사용한 경우는 저분자량 디올의 메틸렌기의 수가 증가할수록 가교화밀도 및 우레탄 농도의 감소로 인해 기계적 성질이 저하되었다. TDI를 사용한 경우는 IPDI와 달리 저분자량 디올의 메틸렌기의 수가 짝수인 경우와 홀수인 경우 그 기계적 성질이 서로 다르게 나타났으며 특히 수소결합의 영향으로 홀수인 경우는 메틸렌기의 수에 따른 지그재그 형상을 나타내었다. The mechanical properties (tensile strength, 100% modulus and hardness) of the urethane elastomers prepared from hydroxyl terminated polybutadiene (HTPB), several low molecular weight diols (ethylene glycol, 1, 3-propane diol, 1,4-butane diol, 1,5-pentane diol and 1,6-hexane diol) and two kinds of diisocyanates(TDI: toluene diisocyanate, IPDI: isophorone diisomechanical properties were enhanced for the increases of the concentrations of the urethane group, as predicted. In case of TDI, when the mechanical properties of the elastomers were plotted patterns were observed, which can be explained by hydrogen bondings depending on the number of the methylene carbons. But the mechanical properties of the elastomers derived from IPDI had decreasing curves against the number of methylene carbons in low molecular weight diols, without the characteristic zigzag patterns.