Micro electrical discharge machining of small hole in TC4 alloy

Aiming at machining deeply small holes in TC4 alloy, a series of experiments were carried out on a self-developed multi-axis micro electrical discharge machining (micro-EDM) machine tool. To improve machining efficiency and decrease relative wear of electrode in machining deeply small hole in TC4 alloy, many factors in micro-EDM, such as polarity, electrical parameters and supplying ways of working fluid were studied. Experimental results show that positive polarity machining is far superior to negative polarity machining; it is more optimal when open-circuit voltage, pulse width and pulse interval are 130 V, 5 μs and 15 μs respectively on the self developed multi-axis micro-EDM machine tool; when flushing method is applied in micro-EDM, the machining efficiency is higher and relative wear of electrode is smaller.