Simulation and Experimental Study on Improving Electrochemical Machining Stability of Highly Convex Structures on Casing Surfaces Using Backwater Pressure

Abstract Casing parts are regarded as key components of aero-engines. Most casing parts are attached to convex structures of different shapes, whose heights range from hundreds of microns to tens of millimeters. Using profiling blocky electrodes for electrochemical machining (ECM) of casing parts is a commonly adopted method, especially when highly convex structures. However, with an increase in the convex structure height, the flow fields of the machining areas become more complex, and short circuits may occur at any time. In this study, a method to improve the flow field characteristics within a machining area by adjusting the backwater pressure is proposed and validated through simulation and experiment analyses. The simulation results demonstrated that the back-pressure method can significantly improve the uniformity of the flow field around the convex structure compared with the extraction and open outlet modes. Subsequently, the back-pressure value was optimized at 0.5 MPa according to the simulation results. The experimental results showed that using the optimized back-pressure parameters, the cathode feed-rate increased from 0.6 to 0.7 mm/min, and a 16.1 mm tall convex structure was successfully machined. This indicates that the back-pressure method is suitable and effective for electrochemical machining of highly convex structures with blocky electrodes. In this study, we propose a method to improve the electrochemical machining stability of a convex structure on a casing surface using backwater pressure, which has achieved remarkable results.