A PRELIMINARY INVESTIGATION OF THE EFFECT OF POSTDEPOSITION POLISHING OF DIAMOND FILMS ON THE MACHINING BEHAVIOR OF DIAMOND-COATED CUTTING TOOLS

The development of deposition technology and applications of diamond-coated cutting tools for machining abrasive materials has now reached a stage where viable cutting tools and machining techniques will soon be a commercial reality. Some early reports in the literature have indicated that polishing of diamond coatings may provide certain benefits in terms of reduction in cutting forces and/or improvement in surface finish of the machined component. The benefits of a polished tool are well known in the industry, as evidenced by the use of polished polycrystalline diamond and cemented carbide tools in the machining of nonferrous materials. The present work was undertaken to investigate polishing of diamond-coated cutting tools and to study the effect of polishing on the machining behavior of such tools. In this paper we report some preliminary results obtained with polished, diamond-coated cemented carbide cutting tools in the machining of Al-Si alloys. The results suggest that polishing of diamond coating allows more efficient cutting owing to improved cutting edge geometry, leading to a reduction in cutting forces and improved chip flow during machining.