A Novel Electric Field Manipulation Method in Through-Mask Electrochemical Micromachining Using a Sacrificial Electrode

Through-mask electrochemical micromachining (TMEMM) is a key technique for fabricating metal microstructures. However, manipulating the electric field to achieve various machining profiles remains a persistent challenge. To address this limitation, this paper introduces a sacrificial electrode into induction electrode TMEMM (IETMEMM) for the first time and proposes a novel method called sacrificial electrode-assisted IETMEMM (SE-IETMEMM). The sacrificial electrode is placed on the photoresist and is electrically connected to the workpiece through the regulating resistor. By adjusting the resistance, the potential of the sacrificial electrode is altered, enabling precise manipulation of the electric field distribution on the machined surface. Specifically, as the resistance increases, the electric field distribution evolves from center concentration to a uniform distribution and subsequently to edge concentration. This evolution is experimentally verified using the machining profiles of gear patterns. At a resistance of 0 Ω, the fabricated specimen exhibits a shallow edge and a deep center, indicating high localization with an etching factor ( EF ) of 10.3. At a resistance of 0.1 Ω, the profile becomes uniformly flat, with a non-uniformity ( Nu ) of only 12.2%. At a resistance of 1 Ω, the fabricated specimen exhibits an island-like profile. Compared with traditional TMEMM, SE-IETMEMM enhances localization by 836.4% at 0 Ω and improves uniformity by 78.1% at 0.1 Ω.