Experimental study on high-efficiency DC short electric arc milling of titanium alloy Ti6Al4V

Short electric arc milling (SEAM) is an efficient electrical discharge machining method, especially for the efficient removal of difficult-to-machine conductive materials with high hardness, high toughness, and wear resistance. In this study, titanium alloy Ti–6Al–4V is used as the research object to conduct machining experiments. The material removal mechanism of SEAM technology is studied using a DC power supply and different tool electrode materials (copper, graphite, Q235 steel, and titanium). The energy distribution of the discharge gap is analyzed using a data acquisition system and a high-speed camera. The arc is found to move with the spindle rotation in the process of arc discharge, and multi-point discharge occurs in the process of single-arc discharge. The voltage and current waveforms and the radius of the etched particles during the experiment are measured; the material removal rate (MRR) and relative tool wear rate (RTWR) are calculated; and the surface and cross-section micromorphology and hardness are analyzed. The experimental results show that when the electrode material is graphite, the maximum feed rate is 650 mm/min; the MRR can reach 17268 mm³/min; the ideal maximum MRR is more than 65,000 mm³/min; and the RTWR is only 1.27%. When the electrode material is Q235 steel, the minimum surface roughness is 35.04 μm, and this material has good stability under different input voltages. When the electrode material is copper, the hardness of the resolidified layer is close to that of the base material, which is beneficial for further processing. The lowest specific energy consumption is 18.26 kJ/cm³ when titanium is used as the electrode material.