Burr height model for vibration assisted drilling of aluminum 6061-T6

Abstract

Vibration assistance has seen increasing application in metal removal processes. One application of this technique is vibration assisted drilling. This method typically induces high-frequency and low-amplitude vibration in the direction of drill feed during drilling, and has the potential to reduce thrust forces and reduce exit burr height. Note that this cutting process is distinct from ultrasonic machining/drilling. Predicting exit burr height accurately is important for determining the favourable vibration conditions for burr height reduction. This paper presents a novel analytical burr height model to predict the exit burr height in vibration assisted drilling of aluminum 6061-T6. This model also improves upon the existing analytical burr height model for conventional drilling. The results of 72 drilling experiments with TiN coated standard twist drills are reported. The predictions from the developed burr height model are compared with the experimental results. The results demonstrate that the proposed model improves the accuracy of the existing burr height model for conventional drilling by up to 36%, and also predicts the burr heights for VAD within a 10% deviation from the mean values of the experimental results. A fast analytical method for predicting the favourable vibration conditions for minimizing burr height is also presented.