Research On Several Issues About Turning Chatter Stability

When chatter occurs in turning, it causes poor wavy surface finishing, and large displacement of the cutting tool will also make the tool away from the workpiece surface, which causes great damage to the cutting tool. Besides, the noise will cause great harm to the worker.This paper considers the influence of deflection of workpiece, inclination angle, side edge cutting angle and the nose radius on turning chatter based on the previous studies. The main work is as follows:The elastic deflection of workpiece is considered and expressed with Timoshenko beam theory, and the natural frequency and mode shapes in certain boundary conditions are acquired. Additionally, with the help of orthogonality condition, the forced response of the workpiece is obtained. The stability analysis is carried out in the frequency domain through the interaction between the workpiece and the tool and the stability lobe diagrams are obtained. Through the comparison of this model and the situation where the deflection of workpiece is ignored, it is found that the critical chip width of the deformed case is always larger than the rigid body case. The effects of workpiece dimensions, cutter flexibility and cutter damping on the difference of stability are also studied.A new oblique cutting model is proposed which contains the influence of inclination angle, side edge cutting angle and the nose radius on chatter. In this model, the stability problem turned into eigenvalue problem. The effects of side edge cutting angle and the nose radius on the stability are discussed in two cases where in the first case, the tool is selected to be more flexible than the workpiece, and in the second case, workpiece is much more flexible than the tool. It indicates that the side edge cutting angle and nose radius have the similar effect, and they all affect the stability by altering the dynamic effects of the tool and workpiece on the stability limit. Besides, when the workpiece is more flexible than the tool, stability is more sensitive to side edge cutting angle and the nose radius, in which case increasing them can reduce the stability drastically.