| EDM has an irreplaceable role in the industry due to its unique advantages.Also, EMD shows low requirement of physical properties of electrode, becauseof its processing characteristics, which makes it possible to deal with the variouselectrodes. This paper introduces the two frequently asked questions in the EDM,and proposes solutions by improving the electrode.(1) Problem1: Loss fast and life short of wire electrode in HSWEDM. Due toMicroscopic characteristics of EDM, the loss of wire electrode in HSWEDM isinevitable. What’s more, its recycling makes wire electrode thinner and thinner inprocessing, and eventually ruptures, affecting the speed of HSWEDM. This paperput forwards an idea that the method of wire electrode compensationscompensates for the loss of wire electrode, and ultimately achieves the aim ofimproving the life of the wire electrode.This paper analyzes the influences of theelectroplating on the wire electrode and designs the electroplating process byusing the method of electroplating to compensate for loss of the wire electrode.Choosing Cu as the electroplating material, experiments are conducted onelectroplating and wire electrode cutting before and after electroplating. Contrastsare made between the surface morphology of various wire electrodes by usingOM and SEM, showing directly the electroplated Cu helps to protect the surfaceof the wire electrodes; analysis are made about different elements contained in thewire electrode surface by EDS, showing electroplating protects the wire electrodefrom the point of view of contained elements. Temperature contours in the processof wire electrodes’ discharging and cooling process are obtained after dischargingby using Ansys simulation software in this paper. Combined with the calculations of enthalpy, heat conducts during instant discharging are obtained, and only about10percent of calories theoretically is transferred to molybdenum after the Cu-electroplated, greatly reducing substrate of the discharging wire electrodes on thepit. Thermal velocity diagram is obtained after the Cu/Mo combined interface andthe separate Mo spark by using the maximum temperature at each timepoint.Calculations shows the cooling rate of the former after discharging is as1.5times quick as Mo-Mo. From the above analysis, this paper draws a conclusionthat Cu-electroplated increases the life of wire electrodes. This paper analyzesfurther theoretically about the electroplating method in compensating for wireelectrode, introducing the partial improvements of electroplating Compensation.Finally, attachment method and composite-electroplating method incompensating the loss of wire electrode are addressed, analyzing their feasibilitysimply.(2) Problem2: Poor chip removal capacity of small hole drilling by EDMand low speed of processing. Because electrode diameter of small hole drilling byEDM is small, chips produce much. As a result, chip troubles the speed of thesmall hole drilling all the time. This paper proposes the method of a spiralelectrode to drill improving the speed of small hole chip removal, and ultimatelyimproves the speed of small hole drilling. This paper analyzes the fluid motionwithin the discharge gap in a spiral electrode. Gap pressure and velocity fields ofSpiral electrode and general electrode are obtained by using the Fluent simulationsoftware. Thus, spiral electrode helps to remove chip more quickly.Finally theexperiments on D703F (high speed small hole EDM machine) are conducted,showing that spiral electrode on small hole drilling by EDM increases the speedby20%.Spiral electrode used in the experiments is analyzed, proposingimprovements and directions for further research on the spiral electrode. |
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