Effects of discharge current and discharge duration on the crater morphology in single-pulse arc machining of Ti6Al4V

Electrical arc machining (EAM) technology offers a competitive and efficient method for removing material from Ti6Al4V alloys. This study investigates the crater morphology and efficient material removal characteristics of EAM. Single-pulse arc discharge experiments were conducted on Ti6Al4V in ambient air with a positive workpiece electrode polarity. The investigation evaluates the impact of discharge current and discharge duration on the diameter, depth, volume of material removal, and the diameter-to-depth ratio of discharge craters. The discharge voltage-current waveform exhibits a delay and a reverse waveform after completion of the discharge. The discharge maintenance voltage throughout the process ranges from 20 to 40 V. The results indicate that an increase in discharge current leads to larger diameters and volumes of material removal. The maximum diameter and material removal volume reach 2430 μm and 0.788 mm³, respectively, significantly surpassing the discharge crater parameters of Ti6Al4V processed by conventional electrical discharge machining. A longer duration could not result in a greater volume of material removal from the craters like discharge current. The derived material removal rate for continuous EAM of Ti6Al4V can reach 11,820 mm³/min at a discharge current of 500 A, a discharge duration of 2 ms and an interval of 2 ms. Higher current and longer duration enable higher energy density and conversion efficiency, resulting in an efficient material removal rate. This study unveils the characteristics of efficient material removal through single-pulse arc machining experiments and the analysis of discharge crater evolution, contributing to a deep understanding of efficient processing efficiency in EAM of Ti6Al4V.