ABSTRACT
In 1927, Krupp introduced Widia cutting tools, the first cWC cutting tools. For a given material, the cutter's life is inversely dependent on its cutting speed. Moreover, the high temperature generated may soften the work material, so the cutter's life may also lengthen. The increase of surface speed of cutting therefore reflects the trend of the cutter's development. Most cWC cutting tools today are covered with a harder coating. However, no matter what combination of ceramic coatings is used, they are still trivial when compared to diamond coating that can easily outperform all non-diamond coatings. CVD diamond coating can be applied to most cWC tools, in particular flat inserts and twisted drills. In order to bond a thick diamond film to a cWC substrate, the author developed world's first brazed thick film diamond cutter. The CVD deposition of diamond film starts with nucleation on cWC with very small grains.
