Electro-discharge drilling with MP-based carbon fibre electrodes

For the electro-discharge drilling of micro-holes with small diameters D the production and the guidance of the tool electrode are most challenging. For holes with diameters D ⤠50 μm the required electrodes have to be produced by electro-discharge dressing, which leads to a considerable increase in the production effort as well as the production costs. The small diameters 5 μm ⤠d ⤠15 μm as well as the good electrical conductivity κ of carbon fibres make it possible to use a single carbon fibre as an electrode for electro-discharge drilling. The paper presents the results of experiments with non-rotating single carbon fibres as tool electrodes for electro-discharge drilling. The process parameters were optimised for the machining of through-holes in a workpiece made of stainless steel 1.4310 with a thickness h = 20 μm and h = 50 μm respectively.