Abstract: Based on the principle of electrochemical reactions, the characteristic and mechanism of nanosecond pulses electro- chemical micro-machining are investigated and the theoretical model of micro-electrochemical machining (ECM) is founded. The affections of electrolyte concentration, electrodes gap and pulse parameters on the result of electrochemical micro-mach- ining are discussed. The practical electrochemical machining system is developed. It consists of micro-machining equipment, nanosecond pulse power supply, electrolyte circulating system, movement control component and process monitoring compon- ent. The effects of pulse on-time and voltage on the side gap of electrodes are investigated with experiments. The result of exp- eriments show that decreasing pulse duration and voltage can enhance the localization and improve electrochemical micro- machining accuracy. On the self-developed equipment, tool ele- ctrode and workpiece are sequentially machining in electro- chemical method. Inter-electrode gap is restrained less than 5 μm. A crisscross micro-groove with 30 μm width and the mic- ro-structure with size 20 μm×30 μm×30 μm is produced. The influence of starting point upon forming precision is analyzed. The experimental results prove that micro-ECM can well meet the demand of micro machining.

Key words: Electrochemical micro-machining, Inter-electrodes gap, Machining accuracy, Nanosecond pulses