Electrode Profile Prediction and Wear Compensation in EDM-milling and Micro-EDM-Milling

EDM-milling and micro-EDM-milling aims to machine deep cavities with rotating electrode; those technologies have a great potential, nevertheless the electrode's wear has to be compensated, which is a big challenge. To achieve this, the electrode profile is of crucial importance as it has a direct impact on the part removed material, but in the same time, the wear modifies this profile. This paper will investigate how the electrode profile is related to tool-path trajectory. It will demonstrate the link between wear, trajectory and electrode profile – both from theoretical point of view and by experimental verification. In case of cylindrical shape electrode with a trajectory in full material, the electrode profile is conically self-shaped. With a zigzag pocketing trajectory the self-shaped profile is more complex but linked with the tool-path overlap in a predictable way: it depends upon the volumetric wear, upon the tool-path overlap, tool-path steepness and the EDM gap. In identical conditions, the EDM gap has for effect to more make the electrode's profile more flat. For the micro-EDM-milling (electrode diameter