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고출력 CW Nd:YAG 레이저를 이용한 인코넬 718 판재 절단시 모서리부 절단 특성 분석
안동규,변경원,Ahn, Dong-Gyu,Byun, Kyung-Won 대한용접접합학회 2008 대한용접·접합학회지 Vol.26 No.5
The objective of this paper is to investigate the effects of the laser power, the material thickness, comer angles, and the loop size on the formation of the comer in the cutting of Inconel 718 super-alloy sheet using high-power CW Nd: YAG laser. In order to investigate the influence of comer angles and loop sizes on the melted area and the formation of comer in the sharp comer, angular cutting tests and loop cutting tests were carried out. The results of the angular cutting tests were shown that the melted area is minimized and the melting mode is changed from nose melting in the thickness direction to the secondary melting induced by the attached dross when the comer angle is $90^{\circ}$. Through the results of loop cutting tests, the variation of the melted area and the comer shape in the sharp comer according to the loop size were examined. In addition, it was shown that a proper loop size is approximately 3 mm. The results of above experiments will be reflected on the knowledge base to generate optimal cutting path of the laser.
고출력 CW Nd:YAG 레이저를 이용한 저탄소 냉연강판 절단시 모서리부 절단 특성 분석
안동규,유영태,Ahn, Dong-Gyu,Yoo, Young-Tae 대한용접접합학회 2006 대한용접·접합학회지 Vol.24 No.4
The objective of present research works is to investigate the effects of process parameters, including the power of laser, cutting speed, material thickness, and the edge angle, on the melted area in the sharp edge of the cut material fur the case of cutting of a low carbon steel sheet using high-power CW Nd:YAG laser. In order to investigate the influence of edge angle and size of loop on the melted area in the sharp edge, angular cutting tests and loop cutting tests have been carried out. From the results of angular cutting tests, the relationship between the edge angle and the melted area has been obtained. The results of the experiments have been shown that the melted area is rapidly reduced from $120^{\circ}$ of the edge angle and the melted area is nearly zero at $150^{\circ}$ of the edge angle. Through the results of loop cutting experiments, the relationship between the cutting angle on the melted area in the edge according to the size of loop have been obtained. In addition, it has been shown that a proper size of loop is nearly 3 mm as the corner angle is greater than $90^{\circ}$ and 5 mm as the comer angle is less than $90^{\circ}$. The results of above experiments will be reflected on the knowledge base to generate optimal cutting path of the laser.
고정형 경계조건에서의 0.7 ㎜ SUS304H 판재의 충격에너지 흡수 특성
안동규(Dong-Gyu Ahn),문경제(Kyung-Je Moon),문형철(Hyung-Chul Moon),한길영(Gil-Young Han),정창균(Chang-Gyun Jung),양동열(Dong-Yol Yang) 한국기계가공학회 2007 한국기계가공학회 춘추계학술대회 논문집 Vol.2007 No.-
The objective of this paper is to investigate into characteristics of the impact energy absorption of SUS304H sheet with thickness of 0.7 ㎜ for the case of the fixed boundary conditions. In order to examine into characteristics of the impact energy absorption, drop impact tests have been performed. Through the results of the experiments, the absorption rate of the impact energy and the deformation characteristics of the specimen have been quantitatively examined. From the results of the experiments, it has been shown that the diameter of the impact head does not affect the absorption energy of the SUS304H sheet. It is also found that the absorption rate of impact energy decreases with increasing of impact energy. In addition, it has been shown that the SUS304H sheet is fractured at the impact energy of 106.6 J when the diameter of the impact head is 10 ㎜.
컴퓨터용 마우스 사출성형 금형의 열특성 개선을 위한 열전도성 금형 설계에 관한 연구
안동규(D. G. Ahn),김현우(H. W. Kim),이기용(K. Y. Lee) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
The objective of this paper is to investigate into the design of the heat conductive mould to improve thermal characteristics of the injection mould for a computer mouse. In order to enhance thermal management characteristics, including the high cooling rate and the uniform cooling, of the mould, a heat conductive mould with three different materials was designed. The materials of the base structure, the mid-layer and the molding part of the heat conductive mould were chosen as Cu-Ni alloy (Ampcoloy 940) to improve the heat conductivity of the mould, Ni-Cu alloy (Monel 400) to reduce a thermal stress, injection tool steel (P21), respectively. Through the three-dimensional transient heat transfer analysis, the influence of the geometrical arrangement of each material on thermal management characteristics was examined. From the results of the FEM analysis, a proper geometrical arrangement of each material was obtained.
안동규(Dong-Gyu Ahn),문경제(Kyung-Je Moon),정창균(Chang-Gyun Jung),한길영(Gil-Young Han),양동열(Dong-Yol Yang) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
The objective of this paper is to investigate the influence of impact conditions on the impact characteristics of the stainless sheet for the case of the fixed boundary conditions. In order to examine impact characteristics of the sheet, three-dimensional finite element analyses and impact tests have been performed. High speed tensile tests have been carried out to obtain strain-stress relationships including the effects of the strain rate. In order to improve an accuracy of the FE analysis, the hyper-elastic model and the damping factor have been introduced. The results of the FE analyses and the impact tests have been shown that the diameter of the impact head does not affect the absorption energy of the stainless sheet. In addition, it has been shown that the absorption rate of energy maintains almost 82.5 - 83.5 % irrespective of the impact energy level and the diameter of the impact head. From the results of FE analyses, the variation of stress and strain energy in the stainless sheet has been quantitatively examined.