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미세 방전 가공에서의 방전 펄스 카운팅을 이용한 간극 제어
정재원(J. W. Jung),고석훈(S. H. Ko),정영훈(Y. H. Jeong),민병권(B. -K. Min),이상조(S. J. Lee) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월
The electrode wear in micro-EDM significantly deteriorates the machining accuracy. In this regard, electrode wear needs to be compensated in-process to improve the product quality. Therefore, there are substantial amount of research about electrode wear. In this study a control method for micro-EDM using discharge pulse counting is proposed. The method is based on the assumption that the removed workpiece volume is proportional to the number of discharge pulses, which is verified from experimental results analyzing geometrically machined volume according to various number of discharges. Especially, the method has an advantage that electrode wear does not need to be concerned. The proposed method is implemented to an actual micro-EDM system using high speed data acquisition board, simple counting algorithm with 3 axis motion system. As a result, it is demonstrated that the volume of hole machined by EDM drilling can be accurately estimated using the number of discharge pulses. In EDM milling process a micro groove without depth variation caused by electrode wear could be machined using the developed control method. Consequently, it is shown that machining accuracy in drilling and milling processes can be improved by using process control based on the number of discharge pulses.
마이크로 팩토리를 위한 미세 방전 가공 장치의 해석 및 제어
유병한(B. H. Yoo),김기원(K. W. Kim),김태곤(T. G. Kim),정재원(J. W. Jung),정영훈(Y. H. Jeong),민병권(B-K. Min),이상조(S. J. Lee) 한국생산제조학회 2005 한국공작기계학회 추계학술대회논문집 Vol.2005 No.-
Electrical discharge machining method is a valuable manufacturing method in the microfactory system. In this study, a model-based process analysis and control methods are developed. The electric discharge power simulation and process simulation can be introduced and the optimization of EDM machining condition for the better understanding of electrical discharge phenomena. For the accurate control of machining depth in EDM, a real time control method is developed using plasma pulse counting. As a result, it is demonstrated that the flat machined surface can be obtatined using the developed control method.
김선주,김유영,김은주,박솔민,배지윤,이민영,이유진,정재원,Li Keying,Wuyingjinzhu,신수진,도지영 이화여자대학교 간호과학대학 2019 이화간호학회지 Vol.- No.53
Purpose: The purpose of this study was to understand the experiences of Gyeongju and Pohang earthquakes during the examinees’ life. Methods: This study applied Colaizzis’s Phenomenological method. The Data was collected through in-depth interviews with a total 8 students of university in Seoul. Results: On the analysis of the interviews, their experience can be expressed as ‘Feeling embarrassed and frightened by earthquakes’, ‘Reduced susceptibility to earthquake hazards due to heavy exam pressure’, ‘Increased exam stress due to earthquake’, ‘Feeling the inadequacy of examinees' earthquake related safety measures in retrospect’. Conclusion: This study was meaningful in deeply understanding of their experiences and revealing that the examinees were more focused on studying rather than actively coping with the disaster. Furthermore, it reconsider the social climate surrounding college admission exams. This study meaningfully discovered that examinees could not stably prepare for both the exam and the earthquake evacuation procedures due to the timing of the earthquake in relation to their upcoming college admission test. Therefore, this study highlighted the examinees’ difficulties due to the earthquakes and increased the necessity of acute phase nursing intervention in relation to the seismic safety education system.