Optimization of EDM Characteristics of WC/5ni Composites Using Response Surface Methodology

Abstract

Electric discharge machining (EDM) has achieved remarkable success in the manufacture of conductive ceramic materials for the modern metal industry. The mathematical models are proposed for the modeling and analysis of the effects of machining parameters on the performance characteristics in the EDM process of WC/5Ni, Which is produced through powder metallurgy route. Response surface methodology (RSM)is used to explain the influences of four machining parameters ; tool rotational speed(S), discharge current(C), pulse-on time(T) and flushing pressure(P) on the performance characteristics of the material removal rate (MRR), and surface roughness (Ra). The experiment plan adopts the central composite design (CCD). The separable influence of individual machining parameters and the interaction between these parameters are also investigated by using analysis of variance (ANOVA). This study highlights that the proposed mathematical models have proven to fit and predict values of performance characteristics close to those readings recorded experimentally with a 95% confidence interval. Results shows that are the two significant factors affecting material removal rate (MRR) are discharge current and flushing pressure. The discharge current, flushing pressure and electrode rotation have statistical significance on the surface roughness (Ra).