Investigation of external capacitance effects on electrochemical discharge drilling

Electrochemical discharge drilling (ECDD) involves a combination of electrical discharge drilling (EDD) and electrochemical drilling (ECD) to remove the recast layer while drilling at high speed. Here, a T-RC power supply similar to the EDD method is adopted. However, the solution resistance characteristics change as a result of utilizing a weak conductivity solution instead of deionized water with insulating properties. Different external capacitances will impact ECDD. In this study, through experiment and simulation, the influence of capacitance on the ECDD performance of Ni-based single-crystal alloy is investigated compared to EDD. In the open-circuit stage, the ECDD current shows an exponential relationship, and the voltage drops slightly. The highest line material removal rate reaches 326 mu m/s, which is higher than EDD, and the tool wear ratio drops by 40%. The aperture and taper continue to ascend. Finally, no recast layer can be realized over 680 nF.