Improvement of trailing edge accuracy in blisk electrochemical machining by optimizing the electric field with an extended cathode

In order to obtain high machining accuracy in the electrochemical machining (ECM), an appropriate cathode design is necessary. Previous cathode employing in radial ECM (called equal-thickness in this paper) leads to considerable distortion of workpiece shape at the trailing edge in machining blisk cascade passages. To improve the accuracy of the trailing edge, electrical field distribution in the inter-electrode gap is simulated in this paper, and a specially designed cathode (called extended cathode in this paper) is developed. The equal-thickness and extended cathodes are compared in experiments. Use of the extended cathode allows fabrication of a workpiece with a shape similar to that of the designed blisk. Compared with the equal-thickness cathode, the allowance difference at the trailing edge is decreased by 31.6% and the surface roughness Ra is decreased by 29.6%.