Experimental Investigation and Optimization of Process Parameter for Inconel 718 Using Wire Electrical Discharge Machining

摘要

Inconel 718 is a nickel-based superalloy having high strength and low thermal conductivity. Due to its properties, wire electrical discharge machining has been selected. The paper reports an experimental investigation of Inconel 718 using zinc-coated brass wire electrode. Based on L27, Box-Behnken design of response surface methodology has been adopted to estimate the effect of process parameter on the machining responses. Four controllable process parameters (viz., wire tension, wire speed, discharge current and pulse-on time) vary, each at three discrete levels, between parametric domains. The following machining responses, in terms of material removal rate (MRR), surface roughness (Ra) and corner deviation (Cd), have been investigated. Finally, an evolutionary computation method has been used based on non-dominated sorting genetic algorithm (NSGA-II) in order to find out the optimal set of solutions for rough-cutting. Experimental data have been used to develop regression models to optimize the process. The adequacy of the developed mathematical model has also been tested by the analysis of variance results. Pareto-optimal settings obtained through NSGA-II have been ranked by gray relation analysis to identify the best optimal set of solutions to avoid lengthiness and impreciseness in the judgment. Confirmation tests have been conducted for optimum machining parameter from the set of Pareto-optimal solutions for proving betterment.