Modelling and Optimization of Hole circularity and Hole Dilation in Electrical Discharge Drilling

Due to thermal nature and electrical discharge, the hole circularity and hole dilation are the main challenging problems during the electrical discharge drilling of different materials. These may be optimized by finding the optimum parameter levels for multi-objective optimization. In this research, hole circularity and hole dilation have been modelled by using experimental data obtained by L-27 Orthogonal array. For the experimentation, discharge current, pulse on time, pulse off time and dielectric pressure have been used as input process parameters. The theoretical validation of the developed models shows that the models may be used for the prediction of hole circularity and hole dilation satisfactorily. Grey relational analysis has been used for the multi-objective optimization of these quality characteristics as Grey relational analysis minimizes the uncertainty of the experimental data. For the optimization, equal weights of both quality characteristics have been considered. The comparison of optimum results with initial parameter setting shows an improvements of 20% and 35% in hole circularity and hole dilation, respectively. (C) 2017 Elsevier Ltd. All rights reserved.