Forced Vibration Mechanism and Suppression Method for Thin-Walled Workpiece Milling

Thin-walled workpieces are widely used in aerospace applications, but their weak stiffness characteristic leads to forced vibration during milling, which reduces the quality of the milled surface. To solve the forced vibration problem in milling thin-walled workpieces, this paper proposes a forced vibration mechanism for the thin-walled workpiece under the influence of various factors and a corresponding suppression method. First, the response characteristics of the thin-walled workpiece excitation features correlated with the mode shape are given. Then, the vibration shapes of the thin-walled workpiece are combined with the cutting position, and the effects of the cutting force frequency and cutting force magnitude are also considered. Finally, the different vibration characteristics are associated with the time constant properties of the shear thickening fluid (STF), and the corresponding forced vibration effects are suppressed by the STF. After a series of experimental modal analyses and cutting experiments, the results show that the proposed theory can explain the forced vibration phenomenon of the thin-walled workpiece, and the vibration suppression effect of the STF is consistent with the theory. The method is also applicable to vibration suppression at the weak position during the machining of the large workpiece.