Mask-Assisted Electrochemical Micro-Etching with Self-Circulating Flushing Based on a Pulsating-Cycle Cathode

The uniformity of microstructural formation remains a critical challenge in mask-assisted electrochemical micro-etching (M-ECME), primarily governed by electric field and flow field distribution. Implementation of a pulsating-cycle cathode in M-ECME enabled self-sustained pulsed machining. Multiphysics simulations verified control over current and flow fields, while theoretical analysis established 0.253 mm as the optimal activation gap. The cyclically moving cathode acts like a piston to refresh the electrolyte in the machining zone, and cathode velocity should be limited to below 0.16 m/s to prevent cavitation in the flow field. Subsequent machining experiments strongly validated these theoretical findings. Optimized parameters (15 V, 0.14 m/s) produce highly consistent microstructures (245.28 ± 5.50 μm diameter, 50.34 ± 5.49 μm depth) with significantly improved dimensional control.