Electrolyte-Jet Interaction and Material Dissolution Behavior in Dual-Headed Nozzle-Based Electrochemical Jet Machining

A key limitation of scaling electrochemical jet machining (ECJM) to multi-nozzle configurations is the loss of localized machining due to electrolyte interactions and electric-field overlap. This work establishes a quantitative design criterion for maintaining localization in dual-jet ECJM through a combined numerical-experimental approach. A two-dimensional multiphysics model is developed to analyze the coupled behavior of electrolyte flow, electric field distribution, and resulting material removal. The results reveal that nozzle pitch governs both hydraulic-jump interaction and current-density confinement. For a nozzle with inner and outer diameters of 220 μm and 450 μm, respectively, a minimum pitch of 2 mm is identified as the critical threshold to suppress electrolyte overlap and stray corrosion, which is validated experimentally with a prediction error below 6%. In micro-grooving, increasing the traverse speed significantly improves surface finish, reducing RMS roughness (Sq) from 648 nm to 242 nm, but at the cost of reduced depth per pass. To address this trade-off, a feed-assisted multi-pass strategy is introduced, enabling deeper machining while preserving surface quality. Using the optimized conditions, uniform micro-groove arrays with a width of 360 μm, depth of 200 μm, and pitch of 666 μm are fabricated in tungsten with high repeatability and minimal stray corrosion.