Utilizing a porous-electrode for the flushing fluid in electrical discharge machining

Abstract

In traditional electrical discharge machining (EDM), abnormal machining phenomena, such as short circuits and arc drawing, are often induced by inter-electrode erosion particles. These result in low machining efficiency and poor surface quality. In this paper, a porous electrode is prepared by high-temperature sintering. The dielectric liquid flows down through the pores in the electrode and then out of its sides to flush the eroded particles rapidly out from between the electrodes, thus reducing the occurrence of these abnormal machining phenomena in EDM and improving machining efficiency. A computational fluid dynamics simulation was used to analyze and compare the flow between the electrodes and the particles flushed out by a single-channel electrode and a porous electrode. The results show that the flow field for the porous electrode is distributed, and it can effectively and quickly remove eroded particles out of the inter-electrode discharge gap. Consistent with the simulation, the experimental results show that porous-electrode EDM can achieve a higher machining efficiency than traditional EDM, and the machining speed is not affected by the machining depth. Moreover, the use of a flushing fluid can avoid the generation of carbon pillars. With the increase of the flow rate of the flushing fluid, due to the dual effects of the flushing fluid reducing the concentration of eroded particles and the flushing fluid interfering with the plasma discharge channel, the material removal rate has a double peak.