Experimental and numerical investigations on fabrication of surface micro-structures using mask electrolyte jet machining and duckbill nozzle


 The consistency in the fabrication of micro surface structures on large workpieces remains a challenge for existing production techniques. Mask electrolyte jet machining (MEJM) is a hybrid mask-based ECM process that combines the flexibility of Jet-ECM to flush the electrochemical by-products and the high throughput processing feature of through mask electrochemical micromachining (TMEMM). In the present study, a duckbill-shaped nozzle is employed in the MEJM for the batch fabrication of micro surface structures which facilitates more uniform current density distribution over the entire machining area, resulting in better consistency. An efficient and high-performance numerical simulation framework with a virtual gap concept is developed for the mask-based ECM processes to simulate micro-cavity profiles and associated current density distribution. Guidelines on how to ensure a smooth electric field transition across the coarse and fine-meshed zones are presented by conducting a quantitative analysis. As an example, this work has successfully fabricated several cavity arrays with different processing parameters. Both the experimental results and the numerical simulation frameworks are easy-to-implement and easy-to-extend for all mask-based ECM processes.