Abstract: Micro-spherical electrode can be widely used in micro machining and measuring filed. To form micro-spherical electrode with high precision and low cost, a new method is presented. Micro-spherical electrode can be fabricated by micro electro-chemical machining (micro-ECM) combined with one pulse electro discharge (OPEG) technology in the electrolysis machine tool. Cylindrical electrode is formed by micro-ECM first, then micro-spherical electrode is fabricated by OPEG technology. The key factors, such as the working polarity, the working voltage, the electric discharge duration, the peak current and so on, which impact the fabrication of the micro-spherical electrode are studied. The results show that a burnished micro-spherical electrode with diameter of about 30 μm can be formed instantaneously based on the micro-cylindrical electrode with about 15 μm diameter. Compared to wire electrode discharge grinding technology (WEDG) combined with OPEG technology, the presented method can form spherical electrodes with better surface quality at lower cost.

Key words: Micro machining, Micro-spherical electrode, One pulse electro discharge