Surface integrity and kerf quality improvement in laser beam machining of Nimonic C-263 by hybrid TOPSIS–grasshopper optimization approach

Nimonic C263, a nickel-based superalloy and has extensive application in the fabrication of high-performance components like casings and exhaust structures in gas turbines, automotive systems and aircraft engines. Conventional machining of this alloy is very challenging as it has high strength, poor thermal conductivity and strong chemical affinity with tool materials. In this research work, laser beam machining is used to machine Nimonic C263 sheets to analyze the influence of laser power (Watts), cutting speed (m/min), gas pressure (Bars) and focal position (mm) on the surface roughness (µm), kerf width (mm), kerf taper (°) and heat affected zone (µm). The outcome of these critical process parameters is evaluated terms of analysis of variance and meticulous scanning electron microscopy analysis on the machines surface. Technique for order of preference by similarity to ideal solution (TOPSIS) is used to combine multiple responses variables into a single response by determining the closeness coefficient and further optimized using a hybrid grasshopper optimization algorithm (GOA) (combined TOPSIS based GOA). A confirmatory experiment is carried out under optimized conditions showing an improvement of 4.84% in overall response, validating the effectiveness of the proposed hybrid approach.