Cutting Performance of PCD Tools Improved by Ultraviolet-Ray Irradiation Polishing

The polycrystalline diamond (PCD) is made of sintered diamond fine powder with binder material, and shows clear isotropic characteristics and high toughness without frequent cleavage. As the PCD cutting tools require relatively low tool cost compared with single crystal diamond tools, they have wide applications as the precision cutting tools with the high abrasion resistance. The more sharp or complex shapes of PCD cutting tool are deeply expected even though they have the machining difficulties. In this study, the ultraviolet-irradiation polishing of single crystal diamond substrates developed in our laboratory (abbreviated as UV-polishing in this paper) was applied to realize advanced PCD tools with ultra-sharp or chamfered cutting edges. Firstly, the UV-polishing properties of PCD substrate were investigated, and high-quality polished surface with 2.6 nmRa was obtained. Secondly, the UV-polishing was applied to the precision polishing of the flank face of PCD cutting tool, and an ultra-sharp cutting edge was finally achieved. The chamfered cutting edge with desired angle and width was additionally formed by the UV-polishing to suppress the chipping left on the sharpened cutting edge. The tool wear of chamfered PCD cutting tools could be reduced almost by half to the sharpened tool under high-speed cutting of high silicon-aluminum alloy.