Investigation of multielectrode multiloop with series capacitance pulse generator for EDM

A novel multielectrode multiloop with series capacitance (MEMLSC) pulse generator is developed to improve the machining efficiency of electrical discharge machining (EDM). In the multielectrode discharge circuit system, each electrode is connected to an independent discharge circuit and forms a singular discharge loop with a common workpiece. A capacitance is serially inserted between each electrode to enhance the discharge and material removal. All the electrodes are coaxial servo-fed to erode workpiece materials. Compared with conventional EDM, which can generate only a singular discharge for each pulse, the MEMLSC pulse generator can dispersedly generate multiple discharges for each pulse. The machining characteristics are evaluated under varying discharge conditions to reveal the dependence of the workpiece material removal rate (MRR) and relative wear ratio (WR) on the capacitance, electrode number, and pulse width. The results of experiments on the MEMLSC and conventional EDM pulse generators show that compared with the latter, the former not only effectively improves the MRR (by more than 6 times) but also provides good machining surface quality and a moderate tool wear ratio (TWR).