Abstract: Aiming at improving the efficiency of micro electrical discharge machining (EDM), the characteristics of micro-EDM was analyzed, the main discharge circuit was improved, and a pulse generator for micro-EDM based on FPGA was developed. The function of gap status detection is integrated that every single pulse can be detected and the harmful discharge pulse can be cut off in time. A sweep pulse circuit was designed. The debris can be evacuated out of the discharge gap by the exploding effect of the sweep pulses, and the gap status can be improved. With this pulse generator, a preferable result is achieved in the experiment of machining of a deep micro-hole on a CNC controlled desktop micro-EDM machine.

Key words: micro electrical discharge machining, pulse generator, sweep pulse, deep small hole