Observation of Bubble Behavior in EDM with Ultrasonic Vibration

• Published in: Procedia CIRP Vol. 113; pp. 267 - 272
• Main Authors: CHENXUE, Wang, SASAKI, Tomohiro, HIRAO, Atsutoshi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2022
• Subjects: Bubble Behavior; EDM; Ultrasonic Vibration; Ultrasonic Vibration; Bubble Behavior; EDM
• ISSN: 2212-8271; 2212-8271
• DOI: 10.1016/j.procir.2022.09.157

In electric discharge drilling the machining speed gradually slows down, when the aspect ratio exceeds 5 (L/D=5). As a solution, the Z-axis of the EDM machine on the market is equipped with a jump function. This function effectively removes machining debris and air bubbles. Also, both pipe electrodes and electrodes with special holes are commercially available. The machining fluid is ejected or sucked from the pipe electrode to remove machining debris and air bubbles between the work gap. Therefore, the working gap is always a clean dielectric working fluid, and as a result, the machining speed does not decrease. However, there are cases in which these functions and pipe electrodes cannot be used. To solve these problems, ultrasonic vibration was applied to the electrodes and dielectric working fluid. It has been reported that EDM with ultrasonic vibration affects machining speed. However, the type of phenomenon that occurs during this process has not been reported. In deep hole drilling by EDM, ultrasonic vibration was applied to the electrodes and dielectric working fluid, and the phenomenon at the side working gap was observed using a high-speed microscope. It was confirmed that the air bubbles existing between the side working gap were more effectively removed by applying ultrasonic vibration. If ultrasonic vibration is not applied, air bubbles coalesce. However, it was confirmed that the air bubbles were not united by applying ultrasonic vibration.