Multi-Objective Optimization of Hole Drilling Electrical Discharge Micromachining Process Using Grey Relational Analysis Coupled with Principal Component Analysis

Abstract

Optimization of performance characteristics and quality characteristics during hole drilling-electrical discharge micromachining (HD-EDMM) is necessarily multi-objective in nature and needs considerable attention for finding preferred operating values and levels for a desired output responses. A hybrid method comprising of grey relational analysis (GRA) coupled with principal component analysis (PCA) is used in this paper for the determination of preferred combination of input parameters of HD-EDMM for maximization of material removal rate and minimization of other three output parameters such as tool wear rate, hole taper and hole overcut simultaneously. The micromachining parameters used are gap voltage at six levels, capacitance of capacitor at three levels and spindle speed at three levels. Eighteen sets of experiments are conducted as per L18 orthogonal array and GRA coupled with PCA is used for finding optimal parameter combination of the HD-EDMM process. Optimal combination of the process parameters for the multi-performance characteristics of the HD-EDMM has been found as gap voltage 140 V, capacitance of capacitor 10 nF, and 110 rpm of tool electrode.