A study on ultrasonic-assisted micro-EDM of titanium alloy

Titanium alloy is widely used in high-precision fields such as aerospace industries and medical equipment because of its corrosion resistance and heat resistance. In conventional micro-EDM, the machining of small deep holes of difficult-to-cut materials has always been a problem due to difficult waste debris discharge and low machining efficiency when the machined aperture is small and the aspect ratio is large. Based on the above shortcomings, the high-frequency ultrasonic vibration was introduced into micro-EDM to improve processability. And the optimal ultrasonic system was designed on analytical calculation, finite element simulation, impedance test, and error analysis. The system was applied to SE-WK008 microporous machine for titanium alloy drilling test, and the univariate control experiment based on ultrasonic parameters and electrical parameters (processing voltage, pulse width, pulse interval, and peak current) was carried out. The influence law of each parameter on processing efficiency and electrode wear was summarized and the experimental data was fitted with polynomial curves, and then the multi-objective particle swarm optimization (MOPSO) algorithm was used to find out the optimal parameter array to verify the correctness of the selected processing parameter group. Through experimental analysis, the designed ultrasonic system can be applied to the traditional microporous machine, the highest processing efficiency is increased by 82.7%, and the maximum electrode wear is reduced by 68.7%, which points out the direction for the parameter selection of actual small deep hole machining.