Study on EDM technology of distributed group electrodes in titanium alloy with large inclined angle and thin-walled group holes

Titanium alloy parts with a large inclined angle and thin-walled group holes exhibit low machining efficiency, poor position accuracy, and difficulties in the manufacturing of small gap grouped graphite electrodes. To achieve the high-efficiency and high-precision machining of such titanium alloy parts, in this study, we propose the electrical discharge machining (EDM) technology based on distributed group electrodes and the tool ball positioning method. Orthogonal process experiments were designed considering process parameters including the peak current, pulse width, duty cycle, and lifting cycle. A comprehensive and intuitive balance analysis method was used to determine the material removal rate, relative electrode loss, and surface roughness, as well as the optimal combination of the process parameters. We constructed the distributed group graphite electrodes and the positioning system of the tool ball, which significantly reduced the machining difficulty of traditional group electrodes and the replacement times of electrodes during machining, and improved the positioning accuracy of electrodes. The results showed that an optimal combination of the parameters could effectively improve the machining efficiency and reduce the electrode loss while ensuring the surface quality requirements. The above-mentioned methods can improve the machining efficiency of the titanium alloy parts with a large inclined angle and thin-walled group holes by more than 1.5 times and significantly reduced the machining accuracy error of repeated positioning.