Effect of ground surface roughness of ball end mill on cutting characteristics

The results of an investigation on the effects of surface roughness on ball end mill are reported here. We used grindwheels with varying in grit between #325 and #1000 to grind ball end mill's rake surface and flank surface, and then coated the end mill with TiAlN film, CrSiN film, and TiSiN film. We measured the state of adhesion on the films on the rake surface in continuous lathe milling as well as the surface roughness and cutting force. 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, we understand 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.