Observation of Bubble Behavior in EDM with Ultrasonic Vibration

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.