Instantaneous fabrication of tungsten microelectrode based on single electrical discharge

This paper presents a new method to fabricate tungsten microelectrode instantaneously by means of the pressure difference of plasma between cathode and anode in a single electrical discharge. The influence of main machining parameters, such as electrode material, polarity, dielectric medium, discharge duration and peak current, is analyzed by detailed experiments to obtain the fabricating law of tungsten microelectrode. The fabricating principle is described clearly. As the result of experiments, a tungsten microelectrode about 350 μm in length and 30 μm in diameter can be fabricated on the top of the tungsten wire of 0.125 mm in diameter by this method. At the tip of the tungsten microelectrode, its radius is about 100 nm. This method can greatly shorten the microelectrode fabrication time and effectively improve the reliability of the microelectrode. Especially, this method can fabricate a nanometer level tip in general electrical discharge machining (EDM) machine tool and need not add any other apparatus. The fabricated microelectrode can be used as a drilling tool in micro-EDM or a probe for scanner and measurement devices.