Segmented and actuated tool electrode for transverse wave flushing in sinking electrical discharge machining (S-EDM)

In sinking electrical discharge machining (S-EDM), high-precision manufacturing processes require numerous tool electrodes for compensating excessive tool electrode wear. The manufacturing of tool electrodes leads to high costs and process times within the process chain. A novel approach is the segmentation of the tool electrode for a variable shaping, which is realised by an actuation of single tool electrode segments using miniaturised linear actuators to perform the roughing process. In addition, the segmentation of the tool electrode allows the implementation of novel flushing strategies. During the process debris particles emerge in the working gap, which need to be flushed out to improve the process conditions and maximise the material removal rate MRR. In this study, the generation of transverse waves is experimentally analysed in a test setup and was modelled in computational fluid dynamics (CFD) to investigate the flushing behaviour of 25 actuated single tool electrode segments. The experimental series showed a direct fluid movement with maximum fluid velocities of v s,max = 62.5 mm/s in the working gap with an actuated amplitude A = 1.5 mm and a frequency f = 5 Hz. This allows a novel efficient flushing strategy in S-EDM to remove debris particles out of the working gap for an increasing material removal rate.