Experimental study of ECDM using a porous electrode containing internal micropores

In electrochemical discharge machining (ECDM), continuous renewal of electrolyte between the tool electrode and the workpiece guarantees stable discharge machining. Proposed in this paper is Porous-electrode ECDM (p-ECDM) using a tool electrode made of porous material containing micrometer pores. The rough surface of the porous electrode promotes electrolyte regeneration between the electrodes to produce a stable and relatively thin gas film. At the same time, the internal connected micropores are used to provide controlled gas flow to the processing area, reduce the energy consumption of electrolytic bubbles, and improve the discharge energy to achieve efficient ECDM processing. Experimental results indicate that compared with a solid electrode, the porous electrode has faster electrolyte renewal, smaller bubble volume, more-stable voltage characteristics, 22.55% less overcut, a 4.7% smaller heat-affected zone, and better deep hole processing ability. Experimental results for p-ECDM assisted by controlled airflow demonstrate a 54.23% increase in the material removal rate.