Cathode shape prediction for uniform electrochemical dissolution of array tools for ECDM applications

The effect of various cathode shapes, i.e., flat-plate, conical, and spherical-shaped cathodes, on the electrochemical dissolution (ECD) behavior of the 3 × 3 area-array tool electrode is presented. The allowed variation in all tip heights is less than 30 μm. Initially, the finite element method (FEM) was used to predicts the reduction in size and heights of the 3 × 3 tips. The spherical shape cathode exhibited uniform current density distribution around the tips, resulting in the consistent dissolution for a longer time than other cathode shapes. Detailed experiments were also performed to predict the dissolution behavior. Experimental results confirmed a similar dissolution behavior. The flat-plate electrode was not suitable in the ECD of array tool electrodes as the difference between the outermost and central tip heights was more than 130 µm, while the difference was less than 30 µm with a spherical-shaped cathode. Electrochemical discharge machining (ECDM) was carried out using the area-array electrodes made by the spherical and flat plate cathodes. The energy channelized by the uniform tips during the ECDM resulted in uniform material removal beneath all the tips, resulting in consistent crater formation. In contrast, a single crater was formed when the non-uniform tips were used.