Effect of cavitation on surface formation mechanism of ultrasonic vibration-assisted EDM

Compared with traditional EDM, ultrasonic vibration-assisted electric discharge machining (UEDM) technology provides excellent machining results for difficult-to-machine materials. There are many factors influencing the material processing. Ultrasonic cavitation bubble collapse has a big impact on UEDM processing. In this study, the influences of shock wave, high temperature, and pressure environment generated by collapse of cavitation bubble on workpiece surface are analyzed. The outer wall movement model of cavitation bubble under ultrasonic action is derived based on the Rayleigh-Plesset bubble dynamics equation. The effect of individual cavitation bubble from the initial state to collapse is simulated in order to reveal the changing trend of surface quality. According to the analysis of experimental and simulation results, it is found that the surface quality of EDM workpiece with ultrasonic cavitation effect is better than that of ordinary EDM. After the addition of ultrasonic, the surface roughness value of the workpiece is reduced by 9.3%-27.9%, while the ultrasonic cavitation effect reduces the surface roughness value of the workpiece by about 17.0%.

Automated summary

Compared with traditional EDM, ultrasonic vibration-assisted electric discharge machining (UEDM) technology achieves superior machining results for difficult-to-machine materials. The collapse of ultrasonic cavitation bubbles has a significant impact on UEDM processing. This study analyzes the influences of shock wave, high temperature, and pressure environment generated by cavitation bubble collapse on the workpiece surface. Experimental and simulation results show that the surface quality of UEDM workpieces with ultrasonic cavitation effects are better than ordinary EDM, with a reduction in surface roughness of 9.3%-27.9%.