Theoretical modeling of energy balance in electroerosion

The power balance of EDM systems for discharge pulses of the order of a microsecond was found to be strongly related to cathode material properties [Investigations of physical processes in wire-EDM by means of single and multiple discharge measurements and analysis, Proc. ISEM XIII, vol. 1, 2001, pp. 473–484]. Although such power balance determines the basic material removal and wear performances in wire-EDM and finishing regimes of die-sinking EDM, it still lacks theoretical description and understanding. In this paper we present a model that relates the power balance for EDM electrodes to the current distribution and potential fall through the electrodes discharge system as well as to the thermophysical properties of electrode materials. Based on electrode erosion data for different metal and alloy arrangements, we present and discuss results for the power balance of short single discharges in terms of the spot current density characteristics, including the amplitude of its ionic and electronic components, and the temperature specific to the cathode materials of the system.