Micro-Electrical Discharge Machining ( - EDM) means the modification of process technologies and machine tools for the manufacturing of micro and miniature parts and structures [ 1 -3]. Compared to conventional die sinking EDM the relative wear can rise up to more than 30% , especially when relaxation generators are used. To achieve shape accuracies in the range of a few microns, it is common to use several tool electrodes for roughing and finishing. In order to reduce the wear and therewith the number of tool electrodes and to enhance the machining results, coated electrodes can be applied. The paper presents results of investigations on wear behaviour of various coatings on tool electrode materials.
