Abstract
Ultrasonic vibration has been applied on micro drilling of hard and brittle materials such as single crystalline silicon and glass etc. and has leaded to superior results. These methods proposed so far, however, need the special equipments to vibrate tool or workpiece. This paper proposes a new ultrasonic vibration method that vibrated the cutting fluid in which tool and workpiece are soaked. This principal is to accelerate the flow of chips by the cavitation generated in the fluid. Micro drilling of SUS304 and aluminum alloy is taken up and the drilling performance is discussed. In addition, the behavior of cavitation is observed with a high-speed camera in drilling of acrylic resin. The obtained results are as follows. Compared with conventional drilling, this method reduces adhesion and/or welding of chip owing to the cavitation generated at the front of the drill and in consequence brings out longer tool life, more stable chip removal and smaller surface roughness. Furthermore, the cooling effect is also superior in various coolant methods.
