Comparison of Electrical Discharge Machining Speed of Tool Electrodes with Different Thermo-physical Properties Related to Ease of Boiling

摘要

This paper reveals the influence of easiness of boiling of tool electrode materials on the machining speed in EDM. It is considered that during the discharge process, both the anode and cathode emit the metal vapor jets into the gap. The interaction of the jets in the gap generates a kind of shear force acting on the molten pool, which helps remove the molten material in the workpiece. Moreover, it was found that lower boiling point of tool electrode results in stronger interaction of the jets and larger shear force, thereby the material removal volume of the discharge crater will be larger. To validate the above thoughts, the effect of the interaction of the jets on the material removal process was investigated through the molecular dynamics simulation. Then, the material removal volume of the discharge crater in a series of single discharge experiments using tool electrodes with different thermo-physical properties related to the easiness of boiling was compared to verify the simulation results. Finally, the machining experiments were performed using a sinking EDM machine to verify the higher removal performance of tool electrode materials which are easy to emit vapor jets.