Analytical Solution For Cathode Design of Diaphragm Through Electrochemical Machining

Author(s): T. Senthilkumar, P. Gopal, B. Chandrasekaran

Abstract: With the rapid progress of aerospace performance, the machining quality and dimensional accuracy of aerospace parts became ever-increasingly important. In order to obtain excellent aerodynamic performance, the shape of aero-engine blades and the diaphragm turns more and more complex. Electrochemical Machining is used to create such complex shapes with high accuracy. It is important in Electrochemical Machining (ECM) to design a tool of appropriate dimension, to produce work piece with desired shape. Analytical methods available in this context are numerical method, analytical method, cos θ method, analogue method, etc. Among them, cos θ method governs more flexibility to deal with the irregularly shaped work pieces. However, it is very difficult to estimate the Inter electrode gap width in the case of curved electrode surfaces. This project attempts to develop a model by cos θ approach of cathode design based on the potential distribution in Inter-Electrode Gap. In order to ensure the convergence of cos θ approach and increase the accuracy in cathode design, the cathode shape should be iterated to eliminate the design errors in computational process. Current density distribution and potential difference between the electrodes are found using COMSOL electrochemistry module. Several experiments have been conducted to verify the machining accuracy of the designed cathode. The experimental results prove the perfect convergence and good computing accuracy of the proposed cos θ approach. The L-shaped work piece is machined and surface finish of 0. 21µm is attained.