Experimental modeling and multiobjective optimization of electrical discharge drilling of aerospace superalloy material

Abstract

In this article, an attempt has been made to optimize the selected input process parameters for material removal rate ( MRR), average surface roughness ( Ra) and average circularity ( Ca) of the hole made by electrical discharge machining in a nickel-based superalloy material especially used in aerospace applications. The concept of twist drill is introduced by attaching a self-developed setup on sinking an electrical discharge machining machine by replacing the actual tool holder of the electrical discharge machining machine and terming it as electrical discharge drilling. Also application of an altogether new approach of hybrid methodology comprising the Taguchi methodology coupled with response surface methodology for modeling and response surface methodology coupled with principal component analysis–based grey relational analysis for multiobjective optimization of process parameters is used. In this application of hybrid methodology, at the first stage, optimum level of process parameters is determined by the Taguchi methodology and used as the central value in response surface methodology for developing the second-order response model, and at the second stage, taking the reference of developed central composite rotatable design matrix of response surface methodology model, grey relational analysis with principal component analysis is applied to determine the grey relational grade for further determination of the optimum level of process parameter. It is observed that with the use of present hybrid approach in this experimental study, an appreciable improvement in MRR by 82.27%, Ra by 39.28% and Ca by 25.00% is achieved, which confirm the viability of using it with future scope for researchers.