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2009
Conference Paper
Titel
Machining of nonconductive ZrO2 ceramics with micro-EDM
Abstract
Tests were undertaken using micro-EDM drilling with Tungsten Carbide Electrodes and ZrO2 ceramic. A starting layer, in literature often referred to as "assisting electrode" was used to set up a closed electric circuit to start the EDM process. The usability of different electrically conductive layers, which were applied onto the substrate surfaces, as well as vibration superposition and different dielectric liquids such as deionised water and carbon hybrid-based EDM-oil was examined. Using a specially designed low-frequency vibration setup to excite the work piece, the process environment could be held within parameters to allow a constant EDM process even after the starting was machined. The machined structures and surfaces topologies were inspected using SEM and EDX technologies. The influences of the process parameters were analysed and an optimized strategy was set up. Using the found parameters and starting layer, micro geometries could be successfully machined into nonconductive ZrO2 ceramic by means of micro-EDM. The material and the thickness of the starting layer proved to be of significant influence. Within the conducted experiments, using a conductive silver-based varnish layer of 20 µm thickness delivered the best result.