Rotational feeding combined with shift feeding in the electrochemical trepanning of a blisk

Abstract

The structure of the blades on a blisk is generally characterized by spatial distortion and spatial bending. Electrochemical trepanning (ECTr) is an effective roughing method in blisk manufacturing. To improve the structural characteristics and the allowance distribution uniformity manufactured by ECTr, a new feeding strategy, in which the relative motion of the cathode and the workpiece is due to simultaneous rotational feeding (RF) and shift feeding (SF), is proposed. The approach is called the rotational feeding combined with shift feeding (RF-SF) strategy. A parametric model and an optimized method for calculating the feeding trajectory (FT) under the RF-SF strategy are presented. To assess the effectiveness of the proposed method, the FTs for a twisted blade with variable cross section and a degree of bending were calculated and simulated for the RF and RF-SF strategies. Compared with the RF strategy, the uniformity of the allowance distribution under the RF-SF strategy was improved by 60.4% and 50.3% at the concave and convex parts, respectively. A blade was machined with RF-SF ECTr. The deviations between the experimental and simulated results were 7.1% and 8.1%, respectively, thereby verifying the effectiveness of the proposed method.