Exit burr height mechanistic modeling and experimental validation for low-frequency vibration-assisted drilling of aluminum 7075-T6 alloy

摘要

The burr influences the surface quality and the performance of the part. Nowadays, vibration-assisted drilling (VAD) is used to decrease the exit burr size. However, further analysis of the VAD burr formation mechanism is required. A mathematical burr prediction model of low-frequency VAD is proposed for the aluminum 7075-T6 alloy cutting. This model includes material deformation mechanisms, multi-region thrust force, and VAD kinematic characteristics. In the material deformation process of VAD, the Johnson-Cook model and fracture model are considered. The results indicate that the experimental burr height is consistent with the model prediction values, and the deviation is less than 8%. The average burr height of VAD decreases by 49.5 %-52.6 % compared with conventional drilling (CD). The parameter analysis shows that the vibration amplitude had the highest sensitivity to the burr height. In the Multivariate regression analysis (MRA), the regression coefficient sum of vibration-related parameters' absolute values (0.676) approximates the sum of other parameters' absolute values (0.817).