Electrochemical Micromachining Using Electrostatic Induction Feeding Method

This paper describes micro electrochemical machining (ECM) using the electrostatic induction feeding method. In ECM, electrolytic dissolution can be localized in the area where the gap width is narrow by using pulse durations shorter than several tens of nano-seconds. With the electrostatic induction feeding method which has been developed for micro electrical discharge machining, the current pulse of such short durations can be obtained more easily compared with the conventional pulse generators. In this study, the influences of the pulse voltage of power supply and feeding capacitance on the machining current were investigated theoretically. It was found that the current pulse duration is nearly equal to the rise time and fall time regardless of the pulse-on time of the pulse voltage. Hence, ultra-short pulses can be obtained without a need to use an expensive pulse generator. Micro-hole drilling carried out in a sodium nitrate aqueous solution with current pulse duration of 30ns showed that significantly small side gap of 2μm could be obtained.