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 brought machines to the market which are able to etch silicon with high etch rates (>5 μm min−1) at high anisotropy (taper of sidewalls <1.5◦). Micromachined silicon is therefore not only suitable for applications in micromechanics but it can also fill the gap which exists between conventional macromachining (milling, turning) with feature sizes usually >1 mm and microelectromechanical systems with feature sizes <100 μm. In this work micromachined silicon is used as a mold for electroplating copper and for hot-pressing silver tungsten. After removing the silicon, the copper or silver-tungsten is used as an electrode for electro-discharge machining. Using these process steps nearly any conductive material can be shaped, in particular magnetic materials like amorphous metal which are difficult or impossible to machine otherwise. The fabrication of the electrodes is described as well as the influence of the electrode material on the achieved quality of the final part.