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RISS 인기검색어
- 검색키워드
- 저자 : Yasuhiro Kakinuma (검색결과 3 건)
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Sangjin Maeng,Hiroaki Ito,Yasuhiro Kakinuma,Sangkee Min 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.1
Machining of steel-based alloy (STAVAX) and tungsten carbide (WC) is very challenging due to their superior hardness. Severe wear in the machining of the die materials is the dominant problem. Texturing on the rake face of the tool and ultrasonic elliptical vibration cutting (UEVC) may resolve this issue and could prolong tool life. The patterns on the rake face of the tool entrap the chip and debris created in machining and prevent abrasion. During UEVC the flank face of the tool does not contact the workpiece and the rake face of the tool helps the chip evacuate from the machining area when the tool disengages with the workpiece. Thus, UEVC reduces cutting force and tool wear compared to conventional cutting. This paper investigates the cutting performance and tool wear in machining of the die materials with textured polycrystalline diamond (PCD) tools under UEVC. The linear patterns parallel or perpendicular to the chip flow are engraved on the rake face of the PCD tools with the focus ion beam (FIB) process. Orthogonal cutting experiments are carried out on ultra-precision machine tools with and without UEVC. Machining under UEVC remarkably reduces the cutting and thrust force and improves tool life. For machining of STAVAX with the textured PCD tool, the linear patterns alone do not improve the cutting, but they improve the cutting when they are combined with UEVC. In machining of WC, the linear pattern becomes effective by slightly decreasing the thrust force and friction coefficient when UEVC is not applied.
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Machinability Study of Single-Crystal Sapphire in a Ball- End Milling Process
Philipp Maas,민상기,Yuta Mizumoto,Yasuhiro Kakinuma 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.1
Sapphire has received increasing attention as an engineering material even though its machinability is still an issue. In this study, the influence of the milling process parameters on the surface quality of single-crystal sapphire is investigated. Due to the hardness and brittleness of the sapphire substrate, crack initiation becomes the main concern with respect to up- and down-milling, feed rate, tool inclination angle and tool wear. With an inclined ball-end mill cutter in feed direction various cutting tests were performed to find optimal parameters for machining microchannel. It was observed that the feed rate and depth of cut are dominant factors for the surface quality. The tool inclination angle shows a parabolic relation to the quality of the machined surface. After tool wear events, such as peeling-off of the tool coating, an increased surface roughness is observed.
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Shuntaro Yamato,Kenichi Nakanishi,Norikazu Suzuki,Yasuhiro Kakinuma 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.2
To maximize the potential for high material removal rates in simultaneous processes such as parallel milling, developing strategies for successful chatter suppression/avoidance is an important concern for manufacturers. In this study, the effectiveness of the spindle speed difference method (SDM) for chatter suppression is discussed in a parallel end-milling process where a flexible workpiece is machined by two tools rotating in opposite direction. The process model is developed, considering that the dynamic variation due to the regenerative eff ect occurs on a plane perpendicular to the tool axis direction. Through the process simulations and the experiments, this study provides informative discussion for comprehending the process behavior. Additionally, a real-time active chatter suppression system with adaptive SDM, where the spindle speed difference is sequentially optimized during the process according to the tracked chatter frequency, is developed by integrating a chatter monitoring system based on sensorless cutting force estimation with sliding discrete Fourier transform. The results show that the developed real-time adaptive system of spindle speed suppresses chatter vibrations more effectively than non-adaptive SDM system; hence, the integrated system can contribute self-optimizing machining systems oriented to Industry 4.0.
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