| dc.description.abstract | In numerous micromachining, electrochemical micro-machining (EMM) also called the electrolytic micro-machining that belong to the non conventional machining. It has more advantages such as any metal material regardless of its hardness can be machined, the cathode tool would not break in the machining process, the work piece after machining will not have any residual stress remained on its surface, the machining reproducibility was high than electro discharge machining. Due to the EMM that disadvantage was the low machining precision. In this paper we discussion the working parameters of EMM that how to effect the machining precision on the manufacture the micro-electrode and hole drilling.
The mircro-electrode has high potential application in non-conventional machining, because the micro-electrode is very thin, generally they are fabricated by micro-electro discharge and laser machining. However, the corresponding equipments are very expensive and their machining efficient is very low. In this reseaech, we applied in the form of electrochemical polish to manufacture the micro-electrode. Under using the DC and pulsed voltage power supply we disscuss the working parameters that how to efeect the micro-electrode’s size and form. For increasing the mass diffusion effect, it added the rotational system in the experimet. Experimental results show that low applied voltage, high concentration electrolyte and an appropriate rotation of electrode are preferred to fabricate micro electrodes with diameter less than 100 μm. From the experiment, it found the rotational speed had critical affect in the form of micro-electrode. When processing the microelectrode by the pulsed voltage power supply, it could fabricate the 100 μm cylindrical tungsten microelectrode and length of 2 mm, 3 mm and 4 mm by linear decay of applied voltage or duty at different length, and we used the micro-electrode to process the electrochemical micro drilling.
In the electrochemical machining of deep holes, especially for small holes, driving out the sludge is always difficult. The hollow tool electrode or lateral flow of the electrolyte cannot be applied to improve the machining precision anymore. In this paper, a rotational tool electrode and a high-frequency pulsed generator were applied herein to drive out the sludge, increase the machining precision and achieve the high aspect ratio hole. By the experiment, a high quality micro hole with a 33.35 μm overcut is drilled by a WC pin of diameter 50 μm on a 304 stainless steel plate of thickness 1000 μm(The hole aspect ratio reaches around 1 : 9.).It shows that a rotational tool can be utilized in the deep hole, electrochemical micro-drilling. In the electrochemical micro drilling with ultral short pulse voltage, by the experiment, it found the relationship between pulsed frequency and overcut was not linear and an excess amount of hydrogen gas bubbles would hinder hole machining, and reduce machining efficiency and precision. Under 30 ns pulsed on-time, a high-quality micro hole with a 13.75 μm overcut is drilled on a nickel plate of 300 μm thick.
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