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국가직무능력표준(NCS) 기반 인쇄분야 국가기술자격 설계 방안
윤종학,김재해,소기호,박계영 한국인쇄학회 2017 한국인쇄학회지 Vol.32 No.1
This study is briefed the national competency standards(NCS) which developed through occupational map analysis in printing fields and the national technical qualifications which were Engineer Printing, Industrial Engineer Printing and Craftsman Printing. And the question for skill test of printing fields was developed by comparing NCS and guideline for question-making. Finally the new system of technical qualification based on printing NCS was designed.
工具壽命을 判定하기 위한 Acoustic Emission(AE) 검출방법의 활용성 연구
윤종학 서울産業大學校 1987 논문집 Vol.26 No.1
Acoustic Emission (AE) is ued to detect the cutting tool failure in the automated machining system, and to detect the micro-scopic processes of the material deformation and failure during the up-set forging. AS the result, we got the following conclusions; 1. It was observed that amplitude level of AE signal was affected by cutting velocity only, and amplitude level of AE signal was directly proportional to flank wear width and the increasing rate was velated to cutting velocity. So, the relation between amplitude level of AE signal and tool life was represented as follow, ?? where, n=0.35, ?? 2.?? is not much affected by feed rate, but drop 10-15% of it's value by lubricating. 3. Also in the plastic deformation on the same forming ratio, the plastic tensile instability point was reached more rapidly on the lubricated condition than non-lubricated and was appeared rapid increase of AE generation by crack and breakage.
윤종학,이호영,이종원 한국공작기계학회 1996 한국생산제조학회지 Vol.5 No.2
This study was focused on the prediction of the appropriate tool life by clarifying the correlation between progressive drill wear and AE signal, on drilling SM45C. the following results have been obtained : RMS_AE , AE CUM-HITS and CUM-CNTS had a tendency to increase slowly according to wear size, at 1000rpm, 150mm/min. However, these increased suddenly in the range of 0.20~0.22mm wear, about 102 holes and had a tendency to go up and down until the drilling was impossible. The sudden increase of AE signal shows that something is wrong and it is closely connected with drill wear and chipping. It also makes the working surface bad. From the above results, AE signal could be sued to monitor the drill's condition and to determine the right time to change tools.
윤종학,여만구,김상헌 한국공작기계학회 1996 한국생산제조학회지 Vol.5 No.3
This study is focused on the prediction of appropriate tool life by clarifying the correlation between progressive tool wear and AE(Acoustic Emission) signals, while cutting stainless steel by end mill on te machining center. The results of this study were that RMSAE tends to increase linearly along with the incrase of the cutting speed, and it was more sensitive to depth of cut than to the variation of feed rate at the same cutting conditions, and RMSAE increases around 0.21mm flank wear hereby AE-HIT also increases. AE signals depend upon tool wear and fracture from the above results. Therefore, the AE signals can be utilized in order to monitor the tool condition.