A finite element based model for electrochemical discharge machining in discharge regime

Electrochemical discharge machining (ECDM) is a promising hybrid process for high-performance machining of non-conductive glass. ECDM drilling has been found to have different characteristics and material removal mechanisms in discharge regime (less than 300 mu m in depth) and hydrodynamic regime (more than 300 mu m in depth); however, these regimes are never separately modeled in existing ECDM models, which leads to large prediction error, especially at low applied voltages and high machining depths. Until now, no model is particularly designed for discharge regime, where most material is removed. In this paper, a finite element based model for ECDM drilling in discharge regime is presented. Material removal subjected to a single spark was simulated using finite element method. The drilling depth evolution in discharge regime was predicted. The model predictions were compared with experimental results for validation. The fraction of power transferred to workpiece was found to be about 29% in discharge regime.