Jerk-controlled micro-electrolysis process for superalloy microhole machining

Producing special-shaped microholes (e.g., reverse/forward tapered, internally shrunken/expanded) with diameters of 100–200 µm remains challenging for microfluidic applications. This study proposes a jerk-controlled micro-electrolysis process to fabricate such geometries in high-temperature corrosion-resistant superalloys. An insulated tungsten carbide microdrill, with its end face exposed, serves as the electrode. The electrode is gradually withdrawn from the hole bottom while rotating under a programmed jerk motion. Localized dissolution, governed by the electric field between the electrode tip and hole wall, is controlled via field duration to achieve nonlinear material removal and diverse profiles. Experiments demonstrate successful fabrication of reverse-tapered and other shapes using a jerk of +0.00002 mm/s³ with a 20 Hz square-wave current. The influences of waveform, kinematics, jerk, and motion accuracy are evaluated, confirming the method’s potential for precise microhole machining.