A novel electrical power supply for electrothermal and electrochemical removal machining methods

For electrically conductive materials Electrical Discharge Machining (EDM), electrochemical machining (ECM) and Electrochemical Discharge Machining (ECDM) constitute a procedure to manipulate materials that are difficult to machine using conventional machining methods. Due to their different electrical behavior all three methods would usually require dedicated power supplies. This paper introduces and analyzes a novel low-loss power supply which can be used for all methods (EDM, ECM, ECDM) without the need for any circuit modifications. Thus it is possible to combine the machining methods in the same mechanical configuration. The mode of operation is explained for EDM and ECM and it will be shown that the proposed power supply is short- and open-circuit proof. The power electronics topology is described in detail as well as the control strategy. Furthermore a prototype for a micro drilling application is shown to validate the theoretical considerations.