Design of ECM tool electrode with controlled conductive area ratio for holes with complex internal features

The design method of electrochemical machining (ECM) tool electrode with controlled conductive area for the machining of holes with given complex internal features was presented in this paper. Such holes were difficult to machine with traditional mechanical machining methods. In authors’ previous work, it has been proved that electrochemical machining (ECM) using tool electrode with controlled conductive area ratio was effective to machine many kinds of complex holes. However, it is considered that the inverse problem, i.e., designing of suitable tool electrode for given internal feature is of great importance for practical application. Therefore, in this work, the proposed ECM process was modeled to investigate the electric potential and current distribution in the electrolyte and on the electrodes’ surface, and the evolution of inner hole profile. Then, the relationship between conductive area ratio and the machining depth was investigated by a set of fundamental simulation experiments. Simulation result showed that suitable tool electrode with specific helical conductive area can be designed for the machining of hole with given internal feature. A prototype tool electrode with non-uniform conductive area ratio from its tip to the root was fabricated and used in the verification experiment. The machining result showed that a free-formed hole was successfully shaped and the inner hole profile is in well accordance with the given internal feature.