Study of surface integrity and effect of process parameters in wire electrical discharge turning of Ti-6Al-4V

Abstract

Wire electrical discharge turning set-up has been developed by modifying the conventional five axes CNC WEDM machine. The main objective of this setup is to achieve cylindrical forms on hard to cut materials. This work focuses on the study of effect of input process parameters like pulse on-time, pulse off time, gap voltage, spindle rotational speed on output responses like surface roughness, material removal rate and wire wear ratio. A mathematical model of responses has been developed using response surface methodology and the optimal value of process parameters has been obtained by desirability function. Surface morphology studies of the machined surface and the worn-out wire has also been elaborated by FE-SEM images. The results show that with an increase in machining parameters value except pulse-on time, all the desired machining outcome decreases. Surface roughness, material removal rate and wire wear ratio have been found in the range of 1.99 µm – 1.37 µm, 7.55 – 13.66 mm³/min and 0.05–0.08, respectively. The formation of thick recast layer over the machined surface has also been discussed. The reduction in wire dimension has been calculated by optical microscopy and its morphology has been discussed by FE-SEM images.