Electro-discharge machining of mesoscopic parts with electroplated copper and hot-pressed silver tungsten electrodes

Recent advances in the development of plasma etchers for silicon has brough t machines to the market which are able to etch silicon with high etch rate s (>5 mu m min(-1)) at high anisotropy (taper of sidewalls <1.5 degrees). M icromachined silicon is therefore not only suitable for applications in mic romechanics but it can also fill the gap which exists between conventional macromachining (milling, turning) with feature sizes usually >1 mm and micr oelectromechanical systems with feature sizes <100 mu m. In this work micromachined silicon is used as a mold for electroplating cop per and for hot-pressing silver tungsten. After removing the silicon, the c opper or silver-tungsten is used as an electrode for electro-discharge mach ining. Using these process steps nearly any conductive material can be shap ed, in particular magnetic materials like amorphous metal which Ie difficul t or impossible to machine otherwise. The fabrication of the electrodes is described as well as the influence of the electrode material on the achieve d quality of the final part.