Abstract
Owing to the inadequacy of modelling electrical discharge machining (EDM) processes based on physical laws, three empirical modelling methods have been adopted in this study, namely, multilayer perceptron (MLP), response surface models (RSM), and high-order polynomials (HOP). To date, no publications regarding the use of the latter approach were found in the literature for modelling EDM processes; there were however some related to the approximation quality of RSM versus that of MLP networks but no investigations assessing the performance of the latter method against HOP. This study attempts to fill this gap by comparing the performance of the three methods mentioned above when modelling an EDM process with a WC-Co workpiece material. Three models were developed to correlate the material removal rate (MRR) with current, on-time, off-time, and capacitance. The half-normal plot and analysis of variance were used to test the significance of the investigated parameters. Due to the complex interdependence pattern that current and pulse on-time exhibited, the approximation of RSM was poor while that of the HOP and MLP models was adequate. A confirmation run based on new factor levels was performed to test the models' generalization. The performance of the HOP model was marginally inferior to that of the MLP, but based on the paired t-test, both models performed equally well.