Research Of Grouped Pulse Power Supply For Micro-EDM

Pulse power supply controls the discharge energy and discharge frequency of micro electrical discharge machining(micro-EDM),and its performance directly determines the machining efficiency and the surface quality of workpiece.In modern processing and manufacturing,the traditional pulse power supply is more and more difficult to meet the processing requirements of high efficiency,high quality and low loss.How to achieve the unification of machining efficiency and machining quality through the design of pulse power supply topology and discharge control strategy has become an urgent problem to be solved in the new type of micro-EDM pulse power supply.This paper is based on the discharge mechanism of micro-EDM and its design requirements for pulse power supply.It starts from four perspectives: improving the discharge frequency,optimizing the charging process of the discharge capacitor,reducing the energy loss,and enriching the discharge control strategy.The main circuit of micro-EDM grouped pulse power supply combines flyback circuit charging and multiple groups of parallel charging-and-discharging circuit structure,and increases switch selective discharge capacitance.According to the characteristics of the circuit,a variety of discharge control strategies are designed,which can realize the accurate control of the discharge energy in a wide range and optimize the discharge gap state during the machining process.The influence of the special load characteristic of micro-EDM gap on the clamp circuit of the flyback primary side and the suppression effect of the clamp circuit on the discharge capacitor voltage rise caused by the no-load state in the machining process are analyzed.According to the above analysis,an experimental prototype of grouping pulse power supply for micro EDM is designed and manufactured.The performance and discharge control strategies of the pulse power supply are verified by using the simulated load.Experiments prove that the pulse power supply grouped pulse discharge control strategy has good discharge consistency and great regulation ability for a variety of discharge parameters.The machining experiment is carried out on the forming EDM machine tool.By gradually reducing the single pulse discharge energy,a good machining effect is obtained,and the surface roughness of the machined workpiece can reach Ra 0.259 μm。...