A semi-analytical model of non-linear vibrations in orthogonal cutting and experimental validation

The aim of this paper is to present an analytical modelling of chatter vibration in orthogonal cutting. With this objective, and to contribute to the understanding of self excited vibration phenomenon, an experimental study was first carried out. The experiments were conducted on a CNC lathe, a special setup was developed to investigate vibration in feed direction. The specimen was a tube and the tool vibrations were measured with an eddy current sensor. Vibration signals, surface roughness and chip morphologies were analysed for different set of cutting conditions in order to define the stability limits of the process. The next part of the study was the modelling of the observed vibration phenomenon. The proposed approach integrated the main sources of non-linearities. In addition, an original aspect of the approach was to associate the vibration model with an analytical thermomechanical model of cutting to estimate the dynamic cutting forces and to deduce the stability limits of the process. A parametric exploration was then presented, different ploughing effect models were evaluated. Finally, the predicted stability limits were compared with those obtained from the experimental tests and from the literature.