The influence of gas-assisted porous electrode on the machining performance of electrochemical discharge machining

In electrochemical discharge machining (ECDM), the structural characteristics of the tool electrode significantly influence the material processing quality. In this study, porous materials with interconnected micron-sized pores are used as tool electrodes in ECDM to realize the compensation of external gases to the gas bubbles around the tool electrodes and to reduce electrochemical energy consumption. A comparative analysis of the force acting on a single bubble at the electrode surface was conducted through modeling. The results indicate that bubbles on the porous electrode surface are more likely to detach from the surface, forming thinner gas film layers. Additionally, simulation analyses of bubble distribution and the gas flow field between the electrode and the workpiece under gas-assisted conditions were carried out, which were further validated through bubble experiments. Compared with traditional solid electrode ECDM, the depth of gas-assisted porous electrode electrochemical discharge machining (IP-ECDM) increased by more than 31 %, while the entry diameter and heat-affected zone were reduced by 10.8 % and 13.5 %, respectively. The hole taper angle decreased by 46.6 %. Finally, the effects of process parameters such as voltage, gas flow rate, and electrode porosity on the IP-ECDM process were investigated using a one-factor method.