Investigation of machinability in turning of difficult-to-cut materials using a new cryogenic cooling approach

A new cooling technique is proposed to improve effectiveness of the minimum quantity lubrication (MQL) and cryogenic carbon dioxide (CO2) cooling in high performance machining of hard-to-cut materials. The combination of minimum quantity carbon dioxide and oil (CMQL) supplied from the rake face are compared with CO2 and MQL supplied from rake and flank faces, respectively, as well as only CO2 supplied from rake face, in turning of Ti6Al4V and Inconel 718. Tool wear, surface roughness and temperature measurements were performed to quantify the cooling impact of the various methods. Based on the systematical test results, CMQL was identified as the most favorable cooling method considering environmental impact, tool wear, surface finish, chip formation and cutting forces.