Influence of dry and solid lubricant-assisted MQL cooling conditions on the machinability of Inconel 718 alloy with textured tool

Machinability of Ni-based aerospace alloy is considered to be difficult due to its numerous intrinsic properties. However, the machining performance of nickel-based alloys can be improved with the geometric alteration on the tool rake zone and by the proper cooling-lubrication mechanism. However, the complete consideration of the proper mechanisms is required. To fill this gap, the impact of cutting speed, machining time, and tool texturing was thoroughly inquired about along with cooling conditions on machinability indices such as tool wear, chip morphology, and cutting forces as well as surface finish. The machining tests were done with textured tools on Inconel 718 alloy at cutting speeds 80, 120, and 180 m/min respectively. Then, the comparison of machining characteristics with or without using solid lubrication mixed minimum quantity lubrication system were made. For that, the time of cutting was restricted to 10 min for comparison purposes. For machining at 80 and 180 m/min, the noteworthy reduction in flank and crater wear was observed, whereas at 120 m/min, small reduction is seen from 1 to 10 min under NFMQL condition. The surface roughness was found to be higher under a dry environment compared to a NFMQL environment due to the low coefficient of friction of MoS₂ at a constant feed rate with an increase in cutting speed. The worst surface finish with maximum of 28.17% difference under dry machining condition was observed. It was clearly seen that the blend of canola oil mixed with MoS₂ particles improved the cooling and friction at the cutting zone. In addition, analysis on the scanning electron microscope (SEM) has been done on the worn tools for better comprehension of tool wear during turning of Inconel 718 alloy. Finally, it has been reported that the performance of the textured tool under solid lubrication conditions is better to achieve a lower tool wear (V_b), surface roughness (R_a), cutting forces, and acceptable form of chips.