High-efficiency DC-SEAM for aerospace materials with Joule-arc heat transition and ignition mechanism

Short electric arc machining (SEAM) is a highly efficient, environmentally friendly, and developing manufacturing method that does not depend on the physical properties of the workpiece. However, there is still a gap in research on the arc ignition mechanism for DC short electric arc machining. This paper proposed an arc ignition mechanism with Joule-arc heat transition and verified its validity by machining current waveforms and a high-speed camera. In addition, the performance of different aerospace materials (Inconel 718, TC4 titanium alloy, and 7075 aluminum alloy) in SEAM was investigated. Experiments revealed the mechanism of arc ignition in DC-SEAM. It was found that machining efficiency, surface roughness, and dimensional accuracy were strongly dependent on the melting points of workpiece materials. In addition, the poor thermal conductivity of the workpiece material accelerated electrode loss. Experiments showed that SEAM of aluminum alloys driven by DC voltage performed better depending on the thermal properties of the material.