Research on a single pulse discharge to discriminate EDM and EAM based on the plasma tunnel and crater geometry

Abstract

Many electro-arc machining (EAM) processes have been put forward in recent years. Theories of electrical discharge machining (EDM) are utilized to study EAM processes frequently. Though EDM and EAM are different in their ranges of discharge current and pulse duration, there is no specific discrimination between EDM and EAM. To find different characters of EDM and EAM, experiments adopting a single pulse discharge were designed and carried out. Fundamental phenomena of EDM and EAM including the plasma tunnel and crater geometry were researched and discussed. Results show that the discharge current and pulse duration influence the diameter and temperature of the plasma tunnel, and then determine the crater geometry, causing a short circuit of the discharge gap finally. Whether a short circuit appeared after a single pulse discharge was researched and adopted for the discrimination between EDM and EAM. A discriminatory line was proposed based on the theoretical analysis and experiments. An experimental verification was conducted and the results were coincident with the deduction.