High-speed dry electrical discharge machining

• A novel high-speed dry electrical discharge machining method was proposed.
• The material removal rate of the high-speed dry EDM can be as high as 5162 mm3/min.
• A thin and discontinuous re-solidified layer is obtained because of the efficient air flushing and electrode rotating.

A novel high-speed dry electrical discharge machining (EDM) method was proposed in this study. Using this method, the material can be rapidly melted by extremely high discharge energy and flushed out of the discharge gap by high-pressure and high-speed air flow. The material removal rate (MRR) of dry EDM was significantly improved by the proposed method. The MRR of dry EDM is usually in tens mm3/min, whereas the MRR of the proposed method can be as high as 5162 mm3/min, which improves the MRR by 2nd to 3rd order of magnitude. Investigation was conducted systemically. The influences of work piece polarity, discharge current, pulse duration time, gas pressure, and electrode rotation speed on machining performance were studied. The machining mechanism of this method was thoroughly analyzed. Moreover, the re-solidified layer, surface morphology, elementary composition, and phase of AISI 304 stainless steel for high-speed dry EDM were also investigated. Theoretical and technical foundations were laid for the industry application of dry EDM.