Energy distribution and material removal of electric arc machining (EAM)

Electric arc machining (EAM), which shares the similar principle as electric discharge machining (EDM), has attracted extensive research interest in the area of electrical machining due to its extremely high material removal rate (MRR). However, the material removal mechanisms of this technology were rarely reported. In this paper, the energy distribution and material removal mechanisms of EAM were systematically investigated. It was found that, compared with the traditional electric discharge machining (EDM), the energy efficiency (the ratio of energy used to remove material from workpiece with regard to the total energy distributed into workpiece) and removal efficiency (the volume ratio of removed material with regard to the total melted material in the workpiece) of EAM is much higher. The removal efficiency of EAM can be as high as 90% whereas it is only about 5% in the case of traditional EDM and no more than 20% in the case of micro EDM. In this work, the energy distribution, material removal mechanisms and characteristics of EAM were deeply investigated and reasons behind the high energy and removal efficiency were explained. Some insightful views were provided by this work, such as materials were removed during the whole discharge, the thickness of recast layer was almost the same as the traditional EDM, the expansion speeds of the discharge generated bubble and ejective debris were calculated.