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5축 Machining Center를 이용한 임펠러 가공을 위한 공구경로 생성에 관한 연구
장동규(Dong Kyu Jang),조환영(Hwan Young Cho),이희관(Hi Koan Lee),공영식(Young Sik Kong),양균의(Gyun Eui Yang) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.3
This paper proposes a tool path generation method for machining impellers with 5-axis machining center. The shape of impeller is complex, being composed of pressure surface, suction surface and leading edge, and so on. The compound surface which is made of ruled surface such as pressure surface and suction surface and leading edge such as fillet surface, makes the tool path generation much complicated. To achieve efficient roughing, cutting area is divided into two region and then tool radius of maximum size that do not cause tool interference is selected for shortening machining time. In finishing, accuracy is improved using side cutting for blade surface and point milling for leading edge.
장동규(Dong Kyu Jang),신재광(Jae Kwang Sin),홍성균(Sung Kyun Hong),이희관(Hi Koan Lee),양균의(Gyun Eui Yang) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.6
This paper presents a method for impeller modeling and 5-axis machining by the reverse engineering. The impeller is composed of pressure surface, suction surface and leading edge, and so on. The surfaces can be modeled by using the characteristic curves such as hub curves, shroud curves and fillet curves. The characteristic curves are extracted from the scanned data and the inspection is performed between the surfaces generated by using the characteristic curves and the scanned data. Then, An impeller is machined by 5-axis macinining and post-processing with inverse kinematic solution.
룰드 곡면으로 된 임펠러의 5축 황삭 가공에 관한 연구
장동규(Dong Kyu Jang),임기남(Ki Nam Lim),양균의(Gyun Eui Yang) Korean Society for Precision Engineering 2007 한국정밀공학회지 Vol.24 No.7
This paper presents an efficient 5-axis roughing method for centrifugal impeller. The efficient roughing is minimization of cutting time through minimizing tool tilting and rotating motions. To minimized cutting time, machining area is divided into sub-cutting regions using control points on hub curves and shroud curves of blade used to design and analyze centrifugal impeller. For sub-cutting regions, diameters of cutting tools are determined as big as possible. Then, tool paths are generated with the tilting axis and rotating axis of 5-axis machine limited and fixed, which can give more efficient machining speed and machining stability than the conventional methods. Experimental results show that the proposed method is more efficient than the conventional methods to mill with the only one cutting tool without dividing area and the previous methods to mill with simultaneous 5-axis processing with dividing area.
Schlieren 기법과 수치해석을 이용한 저압 상황의 초음속 제트 유동 연구
지윤영(Yun Young Ji),장동규(Dong Kyu Jang),손동기(Dong Kee Sohn),고한서(Han Seo Ko) 한국가시화정보학회 2020 한국가시화정보학회지 Vol.18 No.2
Research on shock structures of supersonic jet through visualization experiments in low-pressure environment have not been actively conducted. Therefore, in this study, shock waves and supersonic jets were analyzed and compared by numerical analysis and Schlieren technique at low-pressure. Schlieren technique is commonly used to visualize the shock waves generated by density gradient as interferometric methods. Pressure ratio of entrance and ambient was set around 4 to observe moderate under-expanded jet. For validation of experimental and numerical results, the shock structure and frequency were compared. In the case of ST and C nozzle, the results were shown that the difference of shock cell distance was within 10%. The Mach number gradually decreased due to energy reduction, and the error rate was within 7%. D nozzle was not fitted to be observing the shock structure. Because the interface between rarefaction fan and supersonic jet was ambiguous and oscillating phemenoma occurred at end of jet, the supersonic jet in low ambient pressure was observed and analyzed.