Breakthrough of regenerative chatter modeling in milling by including unexpected effects arising from tooling system deflection

Self-excited anomalous vibrations called chatter affected milling operations since the beginning of the industrial era. Chatter is responsible for bad surface quality of the machined part and it may severely damage machining system elements. Although the significant advances of recent years, state of the art dynamic models are not yet able to completely explain chatter onset even when some conventional cutting tools are applied for conventional milling operations. In this work, a more general model of regenerative chatter is presented. The model takes into account some additional degrees of freedom and cutting forces which are neglected in the classical approach. By so doing, a more accurate representation of milling dynamics is obtained, especially when considering large diameter cutters. An improved mathematical formulation of regenerative cutting forces is provided with respect to a very recent publication where the new model has been first outlined. This approach allows ?45 % of computation time. Moreover, here a new, independent, and stronger experimental validation is provided, where the new model successfully predicts an increase of about +(50 ÷ 100) % of the stability boundaries with respect to the classical prediction, thus showing the potential breakthrough of the new approach.