Effect of Ground Surface Roughness of Tool on Adhesion Characteristics by PVD Coating

The results of an investigation on the effects of surface roughness on adhesion to the coating using the assumed tungsten carbide end mill tip with various degrees of rake surface roughness are reported here. The grindstones with varying in grit between #230 and #1500 were used to grind tungsten carbide tips and then coated the tips with TiAlN film, CrSiN film, and TiSiN film. The state of adhesion on the films on the rake surface as well as the surface roughness and cutting resistance were measured in the continuous lathe turning. The results show that, in generating the cutting cutoff, the optimum grinding roughness differs between the near vicinity of the cutting-edge ridgeline and the part of the rake surface that is further away from the cutting-edge ridgeline. From that fact, it can be understood that the cutting characteristics of the work material and the surface area of the rake surface that is in contact with the cutting cutoff exert their respective influences during the cutting.