Design Of A Novel Micro-EDM Pulse Power Supply And Research On Discharge Gap Characteristics

Micro electric discharge machining(Micro-EDM)is a non-traditional processing technology that uses a controllable electrical energy to form a spark discharge between the electrode and the tool to remove the materials.It can process various conductors and semiconductor materials,especially for the special materials,special structures and complex shape parts that are difficult or impossible to process in traditional contact processing.The pulse power supply in micro-EDM machine tool is the key device for controlling spark discharge energy and discharge frequency,which directly affects technical indicators such as the processing speed,processing quality,productivity,tool electrode loss and process stability of EDM.In this paper,the working principle and topology development of RC,independent and bipolar pulse power supplies are summarized respectively.The characteristics of discharge gap in micro-EDM are studied.The equivalent circuit of RC pulse power supply including parasitic parameters and discharge gap is established.The effects of parasitic parameters on the gap discharge waveform in RC pulse power supply are analyzed by electrical simulation and experiments,and the rationality of the equivalent circuit model is verified.Aiming at the low efficiency and unipolar processing of RC pulse power supply in micro-EDM,this paper proposes a new type of micro-EDM pulse power supply,which can realize both unimpeded and efficient processing and bipolar processing.A discharge energy control strategy with constant frequency and equal energy is proposed to achieve better discharge consistency.The bipolar pulse power supply experimental prototype was designed in the laboratory,and the discharge experiment was carried out on the EDM machine to verify the feasibility of bipolar processing and the discharge energy control strategy.