The wear of 3D microelectrode in micro electrical discharge machining

Three-dimensional (3D) microelectrodes can be fabricated by laminating multilayer copper microelectrodes. When the 3D microelectrode is used for micro electrical discharge machining (micro-EDM), the 3D microstructure can be obtained with an up-and-down reciprocating motion. The process is simple and the machining efficiency is high. In micro-EDM process, the 3D microelectrode has wear, which affects the shape accuracy and dimensional accuracy of the microstructure. To obtain the wear characteristics and predict the wear of the 3D microelectrode, the paper discretized 3D microelectrode into several microelectrodes with square cross-sections. The discretized 3D microelectrodes comprised a number of α-type electrodes, β-type electrodes, and γ-type electrodes. The wear of these microelectrodes was studied by numerous experiments, and the wear characteristics of individual microelectrodes were integrated to obtain the wear characteristics of the 3D microelectrode. The study found that the wear of these three types of electrodes was linearly related to the machining depth. The fit slope of the α-type electrode was equal to − 0.24071, and it had the most wear. The fit slope of the β-type electrode was equal to − 0.21524, and it had the second-highest wear. The fit slope of the γ-type electrode was equal to − 0.19767, and its wear was the lowest. Finally, a 3D microelectrode with semi-cylindrical features was used for micro-EDM to verify the correctness of the wear characteristics. The experimental results were compared with the theoretical calculation, and the theoretical calculation of the 3D microelectrode wear was basically consistent with the experimental results. The maximum error between the theoretical calculation and the experimental results was 21.85 μm, and the minimum error was 3.16 μm.