Chemically vapor-deposited (CVD) diamond has been utilized in diamond brazed cutting tools. Generally, due to the difficulty in producing thick CVD diamond, the tools have conventionally been produced by brazing a diamond film about 300μm in thickness on a cemented carbide used as the base metal for the cutting tool. The production process for such tools is very complex due to the many production steps involved.
A new method in which 200∼300μm thick CVD diamond can be directly synthesized on the cemented carbide has been developed in order to simplify this process. The cemented carbide is cut off by wire electric discharge machining (WEDM) in advance and grid notches are introduced on the carbide by YAG laser beam irradiation making the production of a thick diamond film possible.
The amount of flank wear on a diamond coated tool produced by this method was less than 1/5 of that on a diamond sintered tool. The tool also showed excellent cutting performance, compared with tools produced by the conventional method.