Automated Dressing of Graphite Electrodes for Electrical Discharge Machining (EDM) of Seal Slots in Turbine Components

The die-sinking EDM is applied in the aerospace industry for the machining of seal slots in blades and in structural components made of nickel-base alloys, normally applying graphite electrodes. The objective of this work was the development of a technology to dress the graphite electrodes inside the EDM machine tool, with the aim of rebuilding the original shape of the worn electrodes between EDM cycles. The milestones consisted on (I) understanding the wear behavior of the electrodes while machining the slots, (II) the development of the dressing technology applying the DoE-method and determination of statistically high influencing parameters, and finally (III) the integration of the dressing technology into the process chain.