Christoph Schiffers¹, Ryan Lake_{2, Jeffrey Barlow^2
1}CemeCon AG; Würselen, Germany
^{2CemeCon Inc., Horseheads, NY
Graphite electrodes are essential to EDM machining of molds for plastic injection molding. The extreme abrasiveness of graphite makes diamond coated cutting tools the first choice for this application. A new and very promising business opportunity for cutting tool makers is the direct milling of dental implants from ZrO₂ blanks. A CAD/CAM process creates the individual implant right at the dentist within a short time – very different from the traditional method of using an external dental laboratory.
Graphite electrodes and dental implants are both characterized by very fine, detailed product geometries. This requires very small milling cutters with working diameters down to 0.25 mm. Handling so small and fragile objects is complex for all coating processes. The challenge for the diamond process is to adapt the chemical pre-processing of the carbide substrates, which is essential to the adhesion of the diamond coatings, to the very small milling cutters.
A better understanding of the Hot-Filament CVD process enables a precise control of the growth of the diamond crystals. The full range from coarse crystals for roughing applications down to nano-crystalline diamond coatings for very small ball nose cutters for finishing operations is possible.
Diamond coatings help cutting tool producers to differentiate their products by the outstanding hardness of diamond.}