A High Energy Density Pulsed Power Supply for Micro Electrical Discharge Machining of High Aspect Ratio Holes

Abstract

In micro-electrical discharge machining (EDM), it is difficult to guarantee machining efficiency and accuracy when further increasing the aspect ratio of microholes due to poor circulation of working fluid and removal of debris. In order to increase the ratio of material vaporization erosion and reduce the ejection of large debris caused by material melting, this study proposes a high energy density pulsed power supply that increases the peak discharge current by adding energy-storage inductors with designed charging and discharging control. Machining microholes of diameters from 100 μm to 200 μm with aspect ratios of 10:1, 20:1, and 30:1 show that when the inductance increases from 4.7 μH to 20 μH, the peak current increases by more than two times and the machining efficiency improves by approximately 30%, and the accuracy of the aperture consistency is enhanced, while the occurrence of microcracks on the machined surface is significantly reduced.