Structural modification of WC-Co cutting tools by laser doping treatment.

We have previously shown that sharpening the cutting edge of a cemented carbide tool by chemical-mechanical polishing (CMP) improved the cutting speed by approximately 150% and reduced the wear on the flank surface by approximately 50% compared to a commercial tool when cutting a heat-resistant alloy. In addition, the cutting edges of carbide tools treated by laser doping (LD) using boron nitride as doping material achieved approximately 100 times longer cutting distance in glass machining than the edges of carbide tools treated with CMP grinding wheels. In this study, LD was conducted on a tool base material (WC-Co) to investigate and understand the crystal structure changes of the base material upon treatment. Electron backscatter diffraction and X-ray diffraction results show that the effect of LD was observed in the region 50 nm below the surface. LD improved the strength by approximately 11.7% without destroying the surface crystal structure. Thus, doping can be performed on tool tips while maintaining the WC structure to improve the performance of WC-Co cutting tools.