The Combined Electrode Design And Experiments In Electrochemical Machining Of Blisk

Blisk is one of the important components of aero-engine, its performance directly affects the capability of aero-engine. A blisk combines the blades and the disk together. This simplifies the engine’s structure, lightens the engine’s weight and increases the engine’s performance and reliability. However, it is very difficult to machine an aero engine blisk because of its complicated structure, twisted blade profile, difficult-to-machine material and so on. Electrochemical machining(ECM) has obvious advantages to traditional machining technologies, such as high efficiency, good surface quality, no electrode wear, etc. These advantages make ECM to be a main method for machining aero-engine blisk. In the ECM, the shape of workpiece is guaranteed by the shape of cathode. Therefore, the cathode design is the core technology in electrochemical machining of blisk. Taking the combined cathode in electrochemical machining of blisk as the research objects, this paper studied the design of the cathode structure and the cathode amendment. This dissertation includes four aspects as follows.(1)Design of strengthening rigidity for the combined cathode was carried out. The structure of the combined cathode is limited by the narrow machining space. Unreasonable design of the structure is prone to the space interference or deformation. To design the structure in the blade channel and the structure out the blade channel, the principle is the cathode "straight" track and thickness maximization. Meanwhile, the cathode rigidity in both suction surface and pressure surface rigidly restrict each other. And the non-uniformity distribution of the rigidity could lead to a large deformation in the cathode(2)The optimization method of the combined cathode was proposed.In this paper, a method of optimization in cathode structure was proposed to balance the distribution of the rigidity. The deformation difference between suction surface cathode and pressure surface cathode was used as the objective function, and the minimum value was the optimal solution. The one-way coupling and golden section method were employed with Finite Element Modeling to obtain the optimal structure of cathode.(3)The integrated amendment method of cathode was proposed. This method unified the cathode design, the workpiece measurement and the cathode amendment in a 1D coordinate system along the normal direction of sampling points, which changed the complex 3D amendment to the discrete 1D amendment. The position deviation of correction value is eliminated. Experiments were carried out to verify the cathode amendment method. After a one-time modification of cathode, the machining accuracy of blisk had achieved the drawing requirements. The results indicated that the cathode amendment efficiency was enhanced.(4)Machining experiments of ECM for blisk was carried out. Using the optimal cathode and developed machining system, a blisk sample was machined and achieved the design requirements. The results verified the validity of the research in this paper.