Proposal of ECM method for holes with complex internal features by controlling conductive area ratio along tool electrode

Holes with complex internal features are difficult to machine with traditional mechanical machining methods. In this paper, a novel electrochemical machining (ECM) method using a tool electrode with controlled conductive area ratio to shape the complex inner surface of the hole was presented. The machining process was modeled to investigate the electric potential and current density distribution on the electrodes’ surface and in the electrolyte, and the evolution of the shape of inner surface of the hole. Simulation results showed that the proposed ECM method has the potential to create holes with various complex internal features. A prototype tool electrode with gradually decreased conductive area from its tip to the root was fabricated and used in the verification experiment. The machining result showed that a reverse-tapered hole was successfully shaped and the inner hole profile is in well accordance with the simulation result.