Optimization of WEDM process parameters for D3 die steel using RSM

Abstract

Wire electrical discharge machining is widely used in fields like dies, punches, aerospace and automotive industries for machining conductive, exotic, high strength and temperature resistive materials with better precision and accuracy. Here, to achieve optimal performance is very difficult as there are many process parameters that determine the output characteristics. The objective of the present work is to predict the optimal set of process parameters such as current (I), pulse on/off time (TON/TOFF), wire tension and wire feed to achieve minimum Surface roughness (SR), wire consumption rate (WCR) and maximum material removal rate (MRR). In this work, experiments were carried out by pulse arc discharges generated between brass wire and specimen (D3 die steel) suspended in deionized water dielectric. The experiments were designed based on the five factors and its five levels using full factorial central composite design based on Response Surface Methodology. 52 runs of experiments were constructed based on central composite design procedure and results of the experimentation were analyzed by MINITAB software analytically as well as graphically. Second order regression model has been developed for predicting surface roughness (SR), wire consumption rate (WCR) and material removal rate (MRR) in terms of interactive and higher order machining parameters through response surface methodology. The results revealed that wire tension, current, and their interactions have significant effects on SR, whereas, pulse on time and current have significant effects on MRR and also been observed that wire feed and interaction between current and pulse off time have significant effects on WCR. Finally, the parameters were optimized for maximum MRR, minimum WCR with the desired surface roughness value using desirability function approach.