Investigation On Cross-structual Cathode Design In Electrochemical Machining Of The Leading/Trailing Edges Of Blades

Blade is of critical importance to aero-engine,whose manufacturing level has important effect on performance,safety and reliability of aircraft engine.ECM(Electrochemical Machining)is a main processing method of blade because of its no limitation by mechanical properties of materials,high efficiency,no tool wear,high efficiency with large area machining,mass production of low cost and high surface quality.Leading and trailing edges are indispensable parts of blades,which play a decisive role in aerodynamic performance.The machining of them is the emphasis and difficulty in blade ECM technology,becacuse of thin thickness,small profile radius and complicated structure.Aiming at the cathode design of leading and trailing edges,this paper includes the following researches:1.The simulation of electric field was established for blade ECM,which was based on crossed-structual and traditional cathodes.The variation of electric field at the leading edge was analyzed in the final process of ECM with two types of cathodes.The simulation results showed that the change of electric field was small by using crossed-structual cathodes.2.The design method of crossed-structual cathodes was proposed.The height and offset of crossed-point and crossed-length of cathodes were simulated and optimized.The cathodes were designed based on one uniform-section blade,the accuracy of forecasted leading and trailing edges was within 0.05 mm,which was got by the simulation of electric field.Expreriment was carried out,which indicated that the accuracy of leading and trailing edges was within 0.08 mm,and proved that the design method of crossed-structual cathdoes was accurate.3.The flow field of ECM with crossed-structual and traditional cathodes were simulated,and the simulation results showed that in the final blade process of ECM,the pressure and flow velocity in the machining region of leading edge uniformly variated,by using crossed-structual cathodes.Expreriments were carried out,which indicated that the repeatability of leading and trailing edges machined by crossed-structual cathodes was improved 0.01 to 0.02 mm,and the profiles were more smooth,which compared to blades machined by traditional cathodes.4.Gap-variable maching method was proposed to slove the problem,which was gennrated due to sudden change of flow channel in the ECM of twisted blade.The experiment was carried out,which indicated that by using the distribution processing method,the machining of blade was more stable.5.The crossed-structual cathodes were applied to a certain aeroengine blade,and experiments were carried out.According to the measuring results,the accuracy of concave surface was 58?m,convex surface was 94?m,leading edge was 247?m,trailing edge was 163?m,and the repeatability of leading and trailing edges was 42?m.