Abstract
Glass-like carbon is expected as a die material for mold-press of optical glass devices. In this study, optimum machining conditions on electrical discharge machinability of glass-like carbon die were examined in working fluid such as oil or ion-exchanged water. Short machining time was achieved by electrical discharging in ion-exchanged water, as well as good machined surface with small roughness. This was caused by low electric resistivity of the water and a small amount of isolated carbon. Furthermore, the surface roughness of glass-like carbon discharged in ion-exchanged water was smaller than that done in oil. The glass-like carbon was suitably discharged in ion-exchanged water under conditions of voltage of 40V, electrode rotational speed of 1000∼3000rpm, pulse ON time of 5μs and duty factor of 0.3∼0.7. Under these conditions, excess melting of glass-like carbon, local discharging, adhesiveness of isolated carbon on electrode, etc. were suppressed.
