A Study of Nanometric Surface Generation on Tungsten Carbide Using a Micro Polycrystalline Diamond End Mill
Kazuo Nakamoto*1, Tojiro Aoyama*2, Kazutoshi Katahira*3,
Peter Fonda*4, and Kazuo Yamazaki*5
*1School of Integrated Design Engineering, Keio University, 3-14-1 Hiyoshi Kohoku-ku, Yokohama, Kanagawa 223-0061, Japan
*2Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama-shi 223-8522, Japan
*3Senior Scientist, Materials Fabrication Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
*4IMS-Mechatronics Laboratory, University of California, Davis, One Shields Avenue, 2132 Bainer Hall, MAE Department, Davis, CA 95616, USA
*5University of California, 5136 Etcheverry Hall, Berkeley, CA 94720-1740, USA
The demand for high quality micro-scale molds for the production of high value-added miniature parts is rapidly growing. The fabrication of such molds requires highly productive and high quality micro milling of hard and brittle materials, such as tungsten carbide (WC). Such micro milling processes have not yet been studied well, however, so their fundamental nature is not yet well understood. This paper reports the results of a study on the basic nature of the micro milling process when WC is machined with a custom made PCD (poly-crystalline diamond) micro tool. The study includes the design and fabrication of a custom micro end mill tool with a single cutting edge, experimental procedures to find the optimal machining conditions for high quality surface generation, and an evaluation of the quality of the machined surface in relation to tool wear. The results of the experimental study indicate that machining conditions exist for the generation of a surface with nanometer-level roughness. Normal tool wear is maintained over long cutting lengths while tool wear grows continuously on the axial clearance face of the end mill.
-  R. Wada, H. Kodama, K. Nakamura, Y. Mizutani, Y. Shimura, and N. Takenaka, “Wear Characteristics of Single Crystal Diamond Tool,” Annals of the CIRP, Vol.29, pp. 47-52, 1980.
-  T. Sugano, K. Takeuchi, T. Goto, and Y. Yoshida, “Diamond turning of an aluminum alloy for mirror,” Annals of the CIRP, Vol.36, pp. 17-20, 1987.
-  M. Masuda, Y. Maeda, T. Nishiguchi, and M. Sawa, “A study on diamond turning of Al-Mg alloy – generation mechanism of surface machined with worn tool,” Annals of the CIRP, Vol.38, pp.111-114, 1989.
-  N. Ikawa, R. R. Donaldson, R. Komandri, W. König, T. H. Aachen, P. A. McKeown, and T. Moriwaki, “Ultraprecision Metal Cutting – The Past, the Present and the Future,” Annals of the CIRP, Vol.40, pp. 587-594, 1991.
-  C. F. Cheung, “Characterisation of nanosurface generation in single-point diamond turning,” Int. J. of Machine Tools & Manufacture, Vol.41, pp. 851-875, 2001.
-  D. Dornfeld, S. Min, and Y. Takeuchi, “Recent Advances in Mechanical Machining,” Annals of the CIRP, Vol.55, pp. 745-768, 2006.
-  H. Suzuki, T.Moriwaki, Y. Yamamoto, and Y. Goto, “Precision Cutting of Aspherical Ceramic Molds with Micro PCD Milling Tool,” Annals of the CIRP, Vol.56, pp. 131-134, 2007.
-  X. Cheng, K. Nakamoto, M. Sugai, S. Matsumoto, Z. G. Wang, and K. Yamazaki, “Development of Ultra-precision machining system with unique wire EDM tool fabrication system for micro/nanomachining,” Annals of the CIRP, Vol.57, pp. 415-420, 2008.
-  Z. G. Wang, X. Cheng, K. Nakamoto, S. Kobayashi, and K. Yamazaki, “Design and development of a precision machine tool using counter,” Int. J. of Machine Tools & Manufacture, Vol.50, pp. 357-365, 2010.