Investigation into the blade-formation process in electrochemical trepanning of diffusers

Abstract

Electrochemical trepanning process is an advanced manufacturing technology suitable for the machining of aero-engine components such as blades and diffusers. Tool-electrode (cathode) with special electrical isolation is adopted in the experimental investigations of this article using the electrochemical trepanning to produce a flow mode in which the electrolyte is supplied evenly to the blade being machined. The material removal model for these experiments is built based on the main technical principles of the ECM. For a better understanding of the electrochemical trepanning process during the machining of a blade, computer simulations were previously conducted aiming to observe the geometric shaping of the inter-electrode gap. The shaping process dynamic was analyzed and the distribution of electrical field intensity within the gap has been obtained under different feed rates of the tool-electrode relative to the blade. The profile of the cross-section of the blade was evaluated through the simulation, thus indicating that the blade’s taper angler decrease by increasing the feed rate. Also, practical experiments have been carried out, where the corresponding experimental results proved the simulation was effective. The best taper angle (0.70°) resulted from a machining condition in setting up a feed rate of 4 mm/min, whereas 3.72° was produced using 1 mm/min. Furthermore, a sector with multiple blades was electrochemically manufactured with the optimal set up of experimental parameters, being that the machining accuracy was about 0.12 mm. The application reflected that the method proposed in this article is appropriate and can be used for other complex structures in electrochemical trepanning.