Simulation and experimental study on micro-EDM drilling with shaking-assisted electrode

Micro-electrical discharge machining (micro-EDM) drilling is highly attractive for fabricating micro-holes in high-hardness materials owing to its non-contact material removal mechanism and ability to achieve high machining quality. However, the narrow and uniform side gap characteristic of micro-EDM drilling restricts debris evacuation, thereby deteriorating surface quality and dimensional consistency. To address this limitation, this study proposes a shaking-assisted micro-EDM drilling method. Flow-field simulations of the machining-gap and debris particle dynamics indicate that electrode shaking breaks the symmetric flow-field structure within the machining gap and generates velocity gradients, which facilitate the outward evacuation of erosion debris. Experiments demonstrate that electrode shaking significantly reduces surface defects, in particular, completely eliminating the protrusion defects at the bottom of blind holes caused by debris sintering. The surface roughness (Sa) is reduced by 24.7%, and the taper angle is reduced from 1.52° to 0.73°. For micro-hole arrays, the dimensional consistency at the entrance and exit is enhanced by 21.4% and 17.9%, respectively. Meanwhile, the axial wear length and tapered wear zone length of the electrode are reduced by 13.0% and 14.9%, respectively. These results confirm that the proposed shaking-assisted machining method effectively improves both machining quality and dimensional consistency in micro-holes.