Through-mask electrochemical machining of micro-dimple arrays with synchronization of power switching and cathode movements

Abstract

Micro-dimple arrays with specific shapes and dimensions are crucial for reducing wear and vibration. Through-mask electrochemical machining (TMECM) using flexible cathodes removes materials based on anodic dissolution and allows for efficient processing of large-area micro-dimple arrays. However, the flexible cathode’s tight adherence to the mask can cause sludges from the processing area to stick or aggregate on the cathode surface, which can affect the processing localization of the micro-dimple array. This work introduces a method for TMECM using flexible cathodes which synchronizes the power switching with the cathode movement. Experiments on TMECM were conducted to investigate the changes in the distribution of sludges on the cathode surface. The processing time window for the adhesion and aggregation of sludges was identified. Moreover, the influences of sponge characteristics and processing parameters on micro-dimple machining were investigated. Rules governing the changes in micro-dimple diameter, depth, and bottom surface roughness concerning the sponge’s pore density, compression amount, power conduction time, and effective processing time were established. Ultimately, by adjusting the sponge characteristics and processing parameters, a high-precision micro-dimple array with a diameter of 229.6 ± 2 μm, a depth of 9 ± 0.3 μm, and a bottom surface roughness S a of 0.34 μm and R a of 0.43 μm was fabricated.