Recent advances in cutting tool materials and tool coatings for machining composite materials

The increasing use of a variety of composite materials in high-technology areas like aerospace and automotive industries demands effective cutting tool materials to withstand the high abrasiveness of composite materials, to provide better smoothness to avoid sticking of the composite matrix on the cutting edge, to avoid built-up edges to produce good finished parts, and to withstand the high cutting zone temperature. As machining properties are highly related to cutting tool properties, recent advanced development in cutting tool materials and cutting tool coatings are discussed. High toughness and high hardness are two vital properties for an ideal cutting tool material for cutting composites. So far there are no materials that possess these two vital properties, so many techniques have been applied to cutting tool materials and tool coatings to improve their performance. Surface engineering methods and etching of the substrate are discussed. A smaller particle structure in producing tool materials and tool coatings results in better performance of the cutting tool, such as microgram or ultra fine grain used for cemented carbide tools to improve toughness. Different cutting tool materials and coating techniques and the advantages of nano microcrystalline diamond coating are introduced and explained.