Experimental investigation of hybrid cooling approach using a modified tool holder for turning of Inconel 625 superalloy.

This paper studies the improvement in machining performance by implementing a hybrid coolant approach for the machining of difficult-to-machine Inconel 625 superalloy. This study differs from the pre-existing hybrid cooling methods by using a novel modified tool holder for the supply of cryogenic coolant. An external nozzle is also involved as part of the coolant system to provide MQL spray to the cutting zone in hybrid cooling. Turning experiments using MQL, cryogenic cooling with an external nozzle, cryogenic cooling with a modified tool holder and hybrid cryo-MQL cooling were performed at different parameter levels to analyze the machining performance of the proposed new cooling technique. The results show that a maximum reduction of 30.52%, 63.67%, and 43.27% was observed for surface roughness, tool wear, and cutting forces using the hybrid cooling technique. The tool wear types and mechanisms underlying the wear formation when using various techniques for cooling are studied using SEM imaging of tooltips. Also, the chip morphology study was carried out to compare the effects on machinability. [ABSTRACT FROM AUTHOR]