Fundamental Study on Electrode Performance of Diamond Composite for EDM

抄録

Diamond composites which are made of diamond grains and metals has high thermal conductivity and low coefficient of linear thermal expansion. Therefore, a possibility of diamond composite as electrode for EDM was highly expected. In this study, tool electrode performances of copper-diamond (Cu-Dia) composite and silver-diamond (Ag-Dia) composite in EDM die-sinking were experimentally investigated. The results show that the metal around the diamond grains in the electrode is preferentially removed during EDM under large discharge current condition, which causes the diamond grains to expose on the electrode surface. Consequently, the undulation of electrode surface increases and the discharging state becomes unstable. In order to exert maximum effect of high thermal conductivity of diamond grains and prevent its sign ificant exposure, EDM performance was investigated under the conditions with small discharge current and small discharge area. As a result, the electrode wear ratio of Cu-Dia became lower than that of pure copper. Therefore, Cu-Dia composite has a possibility as an electrode for EDM with small discharge area.