Experimental study on short electric arc machining of Ti6Al4V in terms of power output characteristics

Abstract

As a new development direction for electrical discharge machining, short electric arc machining (SEAM) has emerged as an efficient machining technology for difficult-to-machine conductive materials, as this method is not limited by the strength, hardness, toughness, and other mechanical properties of metal materials. In this paper, the pulse voltage, DC voltage, and DC superimposed pulse (comb) voltage were used as energy inputs to study the SEAM of Ti6Al4V. Experiments were carried out with a graphite tube material as the tool and Ti6Al4V as the workpiece. The current waveform of the experimental process was analyzed; the material removal rate (MRR) and tool wear ratio (TWR) were calculated; and the surface and cross-sectional micro-morphologies and micro-hardness were studied. The experimental results showed that the comb voltage input mode yields the highest machining efficiency, with an MRR of 19,620 mm3/min and a maximum current of 1475 A, which was 35 times higher than that in the conventional pulse voltage input mode. Moreover, the processing was more stable; however, the surface quality was poor. The study results are expected to help select an appropriate processing method depending on the process requirements.