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김기상,김석일 한국공작기계학회 2001 한국생산제조학회지 Vol.10 No.4
One of the important considerations in designing a machine tool is the durability. In this study, a durability estimation system for horizontal machining centers is developed to evaluate the effects of structural specification and driving condi-tions on the durability. All loads such as weights, inertia forces, cutting force and so on, are automatically transferred from the upper elements to the lower elements by the force flows which can he derived from the structural code of horizontal machining centers. And the external loads applied to the motion elements such as beatings, LM guides, ball screws and so on, are determined by the equilibrium conditions of force and moment. Especially, the durability of horizontal machining centers is estimated based on the lifes of motion elements operating under the desired driving conditions.
Preparation of methacrylate copolymers using bulk or emulsion polymerization
김기상,심상연 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0
Poly(methyl methacrylate(PMMA) has been widely used in applications requiring clear durable surfaces. It offers excellent optical properties, high molding precision and low costs. In more common use are surface coatings involving acrylics. A coating of soft material is mainly intended to improve mechanical durability.However, the low surface energy of PMMA may have negative effect on the adhesion of coatings, which is main problem for coating PMMA. To modify surface properties, we prepared copolymers by radical polymerization using bulk or emulsion technique. Methyl methacrylate(MMA), isobornyl methacrylate(IBMA), 2,2,2-trifluoroethyl acrylate(FMA)and 2-hydroxyethyl methacrylate (HEMA) were used as comonomers. Physical properties such as contact angles, glass transition temperature, Td, tensile strength were also studied.
김기상,김석일 한국공작기계학회 2000 한국공작기계학회 추계학술대회논문집 Vol.2000 No.-
In this study, a durability estimation system of turning centers is developed to systematically evaluate the effects of structural specification and testing condition on the durability. All loads such as weights, inertia forces, cutting force and so on, are automatically transferred from the upper elements to the lower elements by the force flow which can be derived from the structural code of turning center. And the external loads applying to the moving and rolling elements are determined by using the equilibrium conditions of force and moment. Especially, the durability of turning center is estimated based on the lifes of moving and rolling elements under the required testing condition.