Optimization of WEDM parameters on surface integrity characteristics of NiTi shape memory alloy

Abstract

The extensively adopted non-traditional approach of wire electrical discharge machining (WEDM) process can be formulated the complicated shapes and difficult-to-cut products with cost effective solution. The surface integrities and mechanical characteristics are sternly affected in the nickel titanium shape memory alloy (NiTi SMA) during WEDM process. In this study, an attempt has been made to investigate the effects of machining parameters on the surface integrity characteristics of NiTi SMA. The machining parameters such as servo voltage, input power, wire speed, pulse-on and pulse-off time were considered as inputs and their effects on surface integrity characteristics such as surface roughness, material removal rate, microstructure and hardness were studied. The machining process has been carried out with three levels of input parameters in the full factorial design. The TOPSIS analysis was used to evaluate the optimum machining parameters in order to exhibit the better surface integrity characteristics for NiTi alloy. The results of the optimization technique revealed that the better surface integrity properties (minimizing the roughness and maximizing the material removal rate) were achieved with the combination of 3 A input power, 9 µs pulse on time, 8 µs pulse off time, 20 V servo voltage and 3 m/min wire speed.