The chaotic characteristics of three dimensional cutting

Chatter is an important problem in turning operations. However, there are very few studies on severe chatter because of the difficulties related to data collection and the complexities associated with non-linear cutting dynamics. In this study, cylindrical turning of long slender bars was simulated at three different cutting speeds by using experimentally identified cutting and structural dynamics transfer functions. The simulations were prepared at various depths of cuts, and variations of the cutting forces and displacements were investigated. Visual inspection and the Lyapunov spectrum of the cutting force signals suggested the chaotic nature of the cutting force signals. Although the frequency of the displacement signal remained constant, the amplitude of the signal appeared to have a chaotic nature. The same characteristics were also observed on the experimental data. During the design of a chatter detection or suppression system, the chaotic nature of the force and displacement signals must be considered. The unpredictable nature of the signals may cause prediction errors.