A three-dimensional FEM model of channel machining by scanning micro electrochemical flow cell and jet electrochemical machining

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In this research, a three-dimensional (3D) finite element method (FEM) model based on Faraday’s law and moving mesh technique is proposed to simulate the channel machining process in Scanning Micro Electrochemical Flow Cell (SMEFC) and jet electrochemical machining (jet-ECM). The scarcity of available FEM models for the channel fabrication by electrochemical machining (ECM) with confined electrolyte is identified through a brief review of ECM simulation with moving electrode. The detailed information on the model establishment is then presented, including the fundamental principle, the way to construct the geometrical model of the moving electrolyte droplet during the machining process, the boundary settings and some key assumptions. Thanks to the introduction of the virtual electrolyte layer and the moving mesh technique, confined machining of channels by SMEFC can be simulated. In the experimental validation phase, species of the electrolyte (NaNO3 and NaCl), the dimension of the hollow electrodes and the electrochemical equivalent of the workpiece, the machining voltages and feed rates are compared in terms of the channel cross-sectional profiles and errors. The flow field and heat transfer still need to be considered in order to simulate the case with NaNO3 electrolyte in the future. This proposed 3D simulation model can improve the understanding and applicability of channel machining by SMEFC, since the current density distribution and the change of workpiece shape can be calculated simultaneously. With some modifications, this method can be as well extended to the channel machining by jet-ECM. Two case studies of micro scale and meso scale jet-ECM are simulated respectively. The proposed simulation method is a potential way to understand and improve the channel machining process by ECM with confined electrolyte.