Selection of optimum performance conditions in the laser-assisted turning of AISI 4340 hardened steel through the coupling of entropy/MCDM analysis

Abstract

The laser-assisted turning (LAT) process comprises complicated interactions between cutting process parameters and laser heating. These interactions pose a significant challenge for predicting and optimizing surface integrity, even though it is crucial for the success of the process and its adoption as an alternative industrial process. This research employs multi-criteria decision-making (MCDM) approaches to determine the optimal machining conditions. The entropy method was applied to assign weights to the criteria, and the MOORA and TOPSIS techniques were utilized to rank the alternatives. A combination of various machining parameters, including feed, cutting speed, and depth of cut were assumed to be the alternatives (machining conditions). Moreover, the white layer thickness, microhardness, and surface roughness were considered selection criteria. The results demonstrated that all parameters are effective for surface integrity. On the other hand, the properties of surface integrity were greatly impacted by the laser power and feed. Therefore, the factors that most affected the creation of the white layer were the feed (47.26%) and the laser power (22.10%). The most advantageous process parameters for the LAT of AISI 4340 steel were found to be a cutting speed of 240 m/min, a cutting feed of 0.07 mm/rev, a cutting depth of 0.5 mm, and a laser power of 450 W by the MCDM analysis.