In making metal cutting tools, four kinds of diamond are used

n making metal cutting tools, four kinds of diamond are used, i. e.natural single-crystal diamond, synthetic single-crystal diamond, polycrystalline at high teoprature and high pressure diamond(PCD) and chemical vapor deposition (CVD) diamond. In recent years, CVD diamond tools are used more and widely. CVD diamond can be used in  two different ways for tool making, i. e. CVD freestanding diamond thick film which can be brazed onto a cemented carbide tool in the same way as PCD and diamond thin film coatcd on a cemented carbide tool. boause of the unique advantages of the thick film diamond tool, it wtll be used in broard applications. This paper is focused on the preparation of diamond thick films, making of diamond film tools and the too cutting performance.