Influence of Electrolyte Concentration on Copying Accuracy of Precision-ECM

A precision ECM process, dimensional accuracy ± 2 μm, surface finish 0.01 μm Ra has been developed using narrow inter-electrode gaps (< 50 μm) for mass production of small (100 mm2) component parts. The electrolyte properties, especially the concentration, play a significant role in controlling the dimensional accuracy of precision-ECM. The relationships between the electrolyte concentration and various process parameters are derived empirically and are utilised in a graphical model to predict the localisation effects of electrochemical dissolution. By controlling the localisation effects significant improvements are made to the dimensional accuracy obtained. Practical examples are used to validate the model developed.