Development of a pulse driven micro-electrical discharge machining for micro-hole boring

Recently, the needs of integrated system for micro-machining and measurement have been increased with the appearance of micro-factory system. For boring electro-conductive high hardness material such as tungsten carbide (WC), an electrical discharge machining (EDM) is much more practical than conventional machining to bore these materials since hardness is not a dominant parameter in EDM. In this study, a pulse driven micro-EDM device for the treatment of conductive high-hardness material is suggested and the micro-hole machining by arc erosion is presented using the method. The characteristics of the developed EDM were analyzed in terms of the electro-optical observation. The discharge images were captured by ICCD camera. Resistance and capacitance are important parameters for EDM. They determine the time constant (tau=RC), so that they decide discharge frequency. Pulsed power broadens the restriction of RC parameters compare with a RC discharge EDM. The pulse driven EDM can change both the discharge frequency and the capacitance for discharge.