Electrical discharge device with direct drive method for thin wire electrode

This paper deals with a new type of drilling device by electrical discharge machining (EDM). This drilling device is much smaller than conventional electrical discharge machines. The drilling device developed consists of two clamps and a driver with piezoelectric elements. It feeds a thin electrode with high response of up to 5 kHz because the inertia of the movable parts is very small. The drilling device is controlled by two modes, the step mode and the hybrid mode. The electrode is driven stepwise in the step mode. In the hybrid mode, the electrode feeds stepwise and it is controlled continuously within the interval between each step. The device performance is investigated through machining of micro holes. It is shown that the drilling device has much higher removal rate than the conventional drilling device for EDM under the same machining conditions. The hybrid mode is more effective on the removal rate under finishing conditions.