A Bipolar Pulse Power Generator for Micro-EDM

Abstract

Based on the researches of alternating arcing phenomena and their influences on the machining performance, a controlled bipolar pulse machining can achieve larger material removal and efficient machining with limited tool wear than unipolar in the same condition, which strengthens the erosion effect in both positive and negative discharge. In this paper, a new type bipolar pulse power generator, using advanced power electronics technology, with discharge energy control strategy for micro-EDM was proposed. A full bridge circuit, which adopts the voltage control during the ignition phase and the current control during the discharge phase, can provide continuous sequence of alternating positive and negative pulse in machining for material removal, anti-electrolysis or smoothing the machining surface. Thus, a fixed discharge frequency with constant energy consumption in each discharge cycle can be achieved, which means efficient and uniform processing.