Realization of Micro-EDM under Ultra-Small Discharge Energy by Applying Ultrasonic Vibration to Machining Fluid

Although micro-EDM has its potential in micro tool and part manufacturing, the machining speed is quite low due to short -circuits and abnormal discharges, because of the difficult debris removal from the narrow gap -width. Especially, the machining becomes impossible under ultra-small discharge energy, for example, a low open voltage and the stray capacitor in the RC discharge circuit. In this study, the effect of applying ultrasonic vibration to the machining fluid in micro-EDM was experimentally investigated, in order to realize higher machining speed and deep -hole drilling. It was found that a significant increase in the machining speed was realized by applying ultrasonic vibration. Also, with the vibration of the machining fluid, micro-hole drilling with ultra-small discharge energy became possible. In addition, the exp erimental results show that the lateral gap width between the tool electrode and workpiece was shortened, and the tool wear ratio became smaller.