CVD diamond tools - fabrication methods and tool applications

The development of activated chemical vapour deposition (CVD) of polycrystalline diamond coatings is of special interest for tool applications because of the high wear resistance of this superhard cutting material. The direct deposition via CVD methods increases the availability of diamond considerably in comparison to conventional high-pressure high-temperature diamond products. CVD diamond is applicable for complex-shaped tools and precision tools with comparatively large dimensions of several ten centimeters. Because of its flexibility with respect to coatable geometries thermal activation by hot filaments (HFCVD) is used for CVD diamond tool applications. Large-scale HFCVD has been developed in the last few years, thus making CVD diamond tools economically attractive. The current status and high potential of CVD diamond technology is demonstrated by prototypes and small-lot fabrication. Results for dry machining of lightweight materials, like for example aluminum alloys and reinforced plastics are highly promising for meeting future demands on tools for high-quality as well as ecological and economical dry cutting processes. CVD diamond coatings with controlled high surface roughness are deposited on different shapes of tools like grinding wheels and abrasive pencils. They are used for precision grinding and structuring of ceramic materials and glass. Microtools with cutting dimensions below 1 mm show increased lifetime for machining of printed boards. They have also been used for micromachining of silicon, ceramics and glass.