Fabrication of Micro-grooves by Applying Laminated Disc Electrodes

Abstract

During the electrical discharge machining (EDM) process, the wear of tool electrodes is inevitable and varies from material to material, thus inevitably degrading the processing accuracy and quality of microstructures. In order to transform this disadvantage into a favourable process, a wear-variation EDM (WV-EDM) method was proposed to prepare a laminated disc electrode (LDE) with stable-profile microchannels on the outer edge surface; subsequently, the electrode was employed to fabricate microgrooves on the workpiece surfaces by EDM. In this study, the difference in wear between the single-disc foil electrodes and corresponding disc foils in the LDE, the formation of the LDE by WV-EDM, the relative volume wear rate of disc foils versus the processing depth, and the distribution of the flow field in the LDE machining gap during machining were investigated, respectively. The results indicate that the proposed approach in this paper could reliably yield LDEs with stable-profile microchannels on the outer edge surface, and then microgroove arrays of the same processing depth could be continuously machined on the workpiece surface of the same material using the EDM method, especially the LDEs did not need to be reshaped. Moreover, due to the protection between the foils, not all disc foils in LDE had the same wear pattern as the single disc foil. In addition, the “pump effect” of the vortex situated in the flow field between microchannels in the LDE and the machining surface facilitated debris removal. Finally, the microgroove arrays and columnar microstructures were produced successfully on Ti-6Al-4 V alloy workpieces using the proposed method.