Design of a tunable mass damper for mitigating vibrations in milling of cylindrical parts

Milling the free-end of cylindrical parts, which are vertically fixed on the machine table, often suffers from large chatter vibrations. This kind of phenomenon is harmful to the cutting process. Therefore, it is of great importance to develop means to suppress these undesirable chatters. This paper proposes a new idea for designing a tunable mass damper (TMD) to reduce vibrations in milling of cylindrical parts. Frequency response function (FRF) of the milling system is derived to comprehensively reveal the influence of both the dynamic response of the machine tools and the TMD. Critical axial depth of cut, which is usually used to characterize the process stability, is formulated by considering the FRFs of both the milling system itself and the TMD. Maximization of critical axial depth of cut is taken as objective function, while kernel dynamic parameters of TMD, which are involved in the derived expression of critical axial depth of cut, are extracted as designable variables. Optimization procedure is carried out to adjust the parameters of TMD by using sequential quadratic programming algorithm. A series of experiments with a designed passive TMD validate that the design has a good performance in reducing vibrations and improving stability of milling process.