Experimental investigation of surface integrity after wire electro-discharge machining of Ti–6Al–4V

Abstract

This article presents the relationship of machining parameters containing pulse-on time (Ton), pulse-off time (Toff), peak current (IP) and servo voltage (SV) on surface integrity characteristics, including white layer thickness (WLT), heat-affected zone (HAZ) and surface crack density (SCD) and also on material removal rate (MRR), after wire electric discharge machining of Ti–6Al–4V. Taguchi’s method was utilized to design the experiments, and response surface methodology (RSM) was employed for developing the empirical models. Results indicated that Ton and IP played a significant role on surface integrity characteristics. In addition, the microstructure of selected machined samples was analysed using a field emission scanning electron microscope (FESEM) and energy-dispersive X-ray (EDX) analysis. Accuracy of models was examined using residual analysis and confirmation runs. Finally, multi-response optimization of process parameters was obtained using desirability approach. Results can be used to improve the quality of the machined workpiece significantly to fulfil the requirements of the various industries. The novelty of this research is mainly investigation and multi-response optimization of all the surface integrity characteristics at the same time.