Simulation and Experimental Study on Improving Electrochemical Machining Stability of High Convex Structure on Casing Surface by Using Backwater Pressure

Casing parts are regarded as one of the key components in aero-engine components. Most casing parts are attached with different shapes of convex structures, and their heights range from hundreds of microns to tens of millimeters. The use of profiling blocky electrodes for electrochemical machining of casing parts is a widely used method, especially in the processing of high convex structures. However, with the increase of convex structure height, the flow field of machining areas will become more complex, and short circuits may occur at any time. In this study, a method to improve the flow field characteristics of machining area by adjusting the backwater pressure is proposed, the simulation and experiment are carried out respectively. The simulation results showed that the back-pressure mehtod can significantly improve the uniformity of the flow field around the convex structure compared with the extraction outlet mode and the open outlet mode, and then the optimized back-pressure of 0.5 MPa was obtained according to simulation results. The experimental results showed that under condition of the optimized back-pressure parameters, the cathode feed-rate increased from 0.6 mm/min to 0.8 mm/min, and the convex structure with a height of 18 mm was successfully machined. This indicated that the back-pressure method is suitable and effective for the electrochemical machining of high convex structure with blocky electrode.