Improved allowance uniformity in multi-tool synchronous electrochemical machining of blisk channels by designing a variable-diameter tube electrode

Multi-tool synchronous electrochemical machining (ECM) is an efficient and cost-effective method for manufacturing blisk channels. The uniformity of the channel allowance has a significant influence on the machining accuracy of the subsequent blade profiles, and the shape of the tube electrode in multi-tool ECM is a key factor affecting the channel allowance distribution. Proposed here is a tool design method for a variable-diameter electrode (VDE) to minimize the tip-to-root allowance difference in channel ECM. The laws governing the formation of a blisk channel under motion in multiple spatial dimensions are analyzed, and the effects of the tube electrode diameter and synthesized speed on the side gap are simulated using electric fields. A mathematical relationship among these factors is established. The tube electrode is discretized into multiple microunits, and their diameters are adjusted to control the side gap and material removal as needed for the channel width, thereby reducing the allowance difference from tip to root. The microunits are then accumulated to obtain the VDE structure. Blisk-channel ECM experiments were conducted using both the designed VDE and an equal-diameter electrode (EDE). The allowance uniformity of the blisk channel machined using the VDE was improved by 32.82 % and 33.07 %, demonstrating the feasibility and effectiveness of using the VDE in the ECM process of blisk channels. By extending the VDE to multi-tool synchronous machining of blisk channels, simultaneous ECM and manufacturing of 10 channels was achieved was significantly improved machining efficiency.