Influence of Coolants on Performance of TiN-PVD Coated HSS Endmills Using to Machine Slot on 1045 Hardened Steel

The application of PVD coating layers on High Speed Steel cutting tools changes frictional interactions between chip and tool materials resulting in a large reduction of temperature generated in the tools. The cutting tools are threrefore able to machine with much longer tool life in dry cutting condition. However, the role of coolants in complex cutting operations using coated tools has not been very well understood. In this paper, the effects of coolants on the performance of PVD-TiN coated HSS endmills are presented. It is clear that in cooling cutting conditions, high cutting forces were shifted toward slower feed rates and high cutting speeds. Good surface roughness was found in the region of high cutting speeds. Moreover, the tool life was evident to be shortened in cooling cutting conditions at high cutting speeds and feed rates. This can be explained by oxidation of the coating caused by the coolant.