Analyses of Burr and Exit Thrust Force of Ultrasonic-Assisted Micro-Drilling

Abstract

With the development trend of miniaturization of product production, ultrasonic assisted micro-drilling technology (UAMD) is more widely used in micro-hole processing due to its unique advantages. In this paper, the effect of 20 kHz harmonic vibration on the exit burr of micro-hole during UAMD has been studied. Based on the self-designed micro-hole drilling cell, a series of experiments have been carried out on the typical difficult-to-process material 30CrNiMo8. The experimental results show that compared with the conventional micro-drilling (CMD), the burr of the hole is well suppressed in the UAMD process, and the height of the burr is reduced by about 27.3 %. The manufactured micro-hole exit burr is relatively neat. While in CMD, the exit burr is deformed greatly, the fracture is obvious, and the exit thrust force is generally larger than that in UAMD.