Attempt to Increase Step Feed by Adding Ultrasonic Vibrations in Micro Deep Drilling

In high aspect ratio micro deep drilling, to shorten the machining time while maintaining the tool life, the addition of ultrasonic vibrations to increase the step feed was examined. First, machining experiments with L/D=10 were conducted, and an increase in the step feed upon the addition of ultrasonic vibrations was confirmed by evaluation of the cutting force and tool wear. Furthermore, micro deep drilling with a high aspect ratio of L/D=20 was examined. Our results reveal that reducing the cutting speed and adding ultrasonic vibrations shorten the machining time by increasing the step feed while maintaining a long tool life. Moreover, we confirmed that the developed technique is effective for the micro deep drilling of holes with a small diameter of 0.1 mm and L/D=15.