Research on depth control of machining trace in electrochemical trepanning

Electrochemical trepanning (ECTr) is a highly effective and economic manufacturing technology for machining difficult-to-cut metal materials that are often used in aeroengine components. Integral structural components such as blisks, diffusers, etc. are composed of hubs and blades. In continuous ECTr, machining trace stems from on the hub between adjacent blades. The depth of machining trace significantly influences the surface integrity of the integrated components, even causes the scrapping of the workpiece. In order to solve the problem of machining trace in ECTr, a cathode design method based on the relation between cathode profile and electric field distribution is proposed in this study, the edge of the cathode that affects the machining trace is chamfered. A electric field model of ECTr is established and dynamic electric field simulation of ECTr for cathodes with different chamfered edges is performed. The electric field intensity distribution at the cathode edge and the forming profile of the hub are compared. The simulation results show that optimal chamfering parameters can improve the machining trace. Subsequently, a group of cathodes with different chamfered edge is designed, and corresponding ECTr experiments are conducted. The optimal chamfering parameters are determined (α = 5°, b = 2 mm), the depth of the machining trace is reduced from 0.370 mm to 0.122 mm, the surface flatness is significantly improved. Overall, this depth control method of machining trace is verified effectively.