Investigation of inner-jet electrochemical milling of nickel-based alloy GH4169/Inconel 718

Abstract

Electrochemical machining (ECM) has several advantages for processing difficult-to-cut materials such as no tool wear and high machining efficiency. Electrochemical milling integrates the capability of ECM and the flexibility of numerical control (NC) technology, which can mitigate substantially the difficulty of the complicated tool design in ECM. This paper proposes a flow channel structure for a rotating electrode with a dead-end tube used for electrochemical milling of nickel-based alloy GH4169/Inconel 718 in which some electrolyte outlets are located in the side wall of the electrode. The number of electrolyte outlets is determined reasonably well through flow field analysis with the aim of distributing the electrolyte flow more uniformly. Experiments show that the material removal rate, the surface quality, and the uniformity of the machining gap can all be significantly improved with an increased feed rate. When the machining depth is 3 mm in one pass, a feed rate of 2.1 mm min−1 is achieved experimentally with a suitable combination of machining parameters. Finally, a sample with thin-walled structures is produced stably at a feed rate of 2.1 mm min−1 and a machining depth of 3 mm, in which the feed direction changes six times and the total processing distance is 94.6 mm. The inner-jet electrochemical milling with the proposed electrode has a good efficiency and stability for processing thin-walled components with a large removal depth.