3.16 Hard Coatings on Cutting Tools and Surface Finish

Performance of a machined part surface depends mostly on surface finish obtained on that part. Surface roughness, residual stress, microstructure, and hardness are some characteristics of the machined surface to be taken into account. Deposition of a hard coating on cutting tools improves the quality of surface finish by means of protection of the tool’s cutting edge geometry together with decreasing friction coefficient and cutting temperatures. The subject of this chapter is hard protective coatings, deposited by physical vapor deposition and chemical vapor deposition methods. An extended overview of fundamental effects of hard coatings on surface finish is performed.