Effect of cryogenic compressed air on the evolution of cutting force and tool wear during machining of Ti-6Al-4V alloy

The effect of cryogenic compressed air cooling on tool wear and cutting forces during cutting Ti-6Al-4V alloy has been investigated at two cutting speeds at which cutting tool fails as the result of gradual flank wear and catastrophic plastic deformation of the cutting edge, respectively, during dry machining. It is found that the application of cryogenic compressed air dramatically increased tool life compared with dry machining, and the increase in tool life was more significant at higher cutting speed as the plastic deformation of cutting edge that occurred during dry machining was suppressed during machining with cryogenic compressed air cooling. The improvement of tool life with application of cryogenic compressed air cooling during machining is attributed to the low temperature and high pressure of cryogenic air jet, which leads to the reduction in cutting temperature due to the enhanced cooling and reduction in tool-chip contact length. Low cutting temperature results in reducing wear rate, size of chip built-up edge and maintaining the strength of the cutting edge in order to resist plastic deformation.