Energy-saving Flyback Converter for EDM Applications

Electrical discharge machining (EDM) uses controlled electric sparks to erode the metal in a workpiece, and this method is now a well established machining process for high power applications. EDM power supplies utilizing different topologies for high power applications (e.g. full bridge configuration) are widely available. Through the years, EDM processes have increasingly been used in high precision machining and in manufacturing micromechanical components, with new low power topologies being investigated for the latter. We implemented a current mode flyback converter for use in low power EDM applications. This topology has an energy conservation feature and removes the need for output bulk capacitors. Energy used in the erosion process will come from the energy stored in the flyback transformer and will be transferred to the small output filter capacitors and the effective capacitance of the tool, workpiece, and dielectric combination. A servomechanism that controls the arc distance will determine the output voltage. We have developed an EDM power supply prototype utilizing the flyback topology for low power applications with minimal components count and inherent protection under short circuit conditions. Our work includes the design, fabrication, and characterization of the whole system. We compared the efficiency and quality of work of our proposed topology with that of a linear converter.