| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 100 === With the development of micro machining or measurement technology, the demand for micro-spherical tools or probes such as using for micro-hole machining, coordinate measuring machine (CMM) and chip test has been rapidly increasing. Electrochemical micro machining (ECMM) is one of nonconventional micromachining processes; its material removal is an anode electrochemical dissolution process. The anodic electrochemical dissolution occurs when a voltage is applied between anode and cathode placed in electrolyte. This paper demonstrates a finishing process using ECMM (ECMF) to build an accurate and smooth micro-spherical tungsten electrode. A micro tungsten electrode is made by several processes including wire electro-discharge grinding (WEDG), electric discharge machining (EDM) spherical forming, and ECMF. The influence of ECMF parameters on the EDMed surface and tool diameter is presented.
The experimental result shows a smooth micro-spherical tungsten electrode can be successfully finished and brightened with suitable ECMF parameters that are a voltage of 16 V, electrolyte concentration of 2 wt% and machining time of 0.5 second. When using this method, not only the micro tungsten electrode has a smooth surface and but also its diameter can be fine-tuned to get the high accuracy via the machining time control. Finally, the electrode is tested to drill a micro hole to compare with the machining performance by using conventional cylindrical electrode.
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