Productivity of the high speed milling operations can be seriously limited by chatter occurrence. Several studies on this self-excited vibration can be found in the literature: simple models (1 or 2 dofs) are proposed, i.e. a lumped parameter model of the milling machine being excited by regenerative, time-varying cutting forces. In this study, a new model of the milling machine is proposed: the machine frame and the spindle were modeled as an experimental evaluated modal model, while the tool was modeled by a discrete modal approach, based on the continuous beam shape, analytical eigenfunctions. The regenerative cutting force components lend to a set of Delay Differential Equations (DDEs) with periodic coefficients; DDEs were numerically integrated for different machining conditions. The stability lobe chart was evaluated using the semi-discretization method. Time histories, spectra and Poincaré maps related to the vibratory behavior of the system were numerically obtained and differences with respect to the bifurcations predicted by the simplest models known in literature are pointed out. Some different behaviors in the shape of the stability lobe charts and in the spectra of the chatter vibrations were also observed.
A coupled theoretical-experimental dynamical model for chatter prediction in milling processes / G. Catania; N. Mancinelli. - ELETTRONICO. - 1:(2009), pp. 1-10. (Intervento presentato al convegno Proceedings of the ASME 2009 Design Engineering Technical Conferences & Computers and Ingormation in Engineering Conference (IDETC2009) tenutosi a San Diego, CA, USA nel August 30 - Sept. 2, 2009).
A coupled theoretical-experimental dynamical model for chatter prediction in milling processes
CATANIA, GIUSEPPE;MANCINELLI, NICOLO'
2009
Abstract
Productivity of the high speed milling operations can be seriously limited by chatter occurrence. Several studies on this self-excited vibration can be found in the literature: simple models (1 or 2 dofs) are proposed, i.e. a lumped parameter model of the milling machine being excited by regenerative, time-varying cutting forces. In this study, a new model of the milling machine is proposed: the machine frame and the spindle were modeled as an experimental evaluated modal model, while the tool was modeled by a discrete modal approach, based on the continuous beam shape, analytical eigenfunctions. The regenerative cutting force components lend to a set of Delay Differential Equations (DDEs) with periodic coefficients; DDEs were numerically integrated for different machining conditions. The stability lobe chart was evaluated using the semi-discretization method. Time histories, spectra and Poincaré maps related to the vibratory behavior of the system were numerically obtained and differences with respect to the bifurcations predicted by the simplest models known in literature are pointed out. Some different behaviors in the shape of the stability lobe charts and in the spectra of the chatter vibrations were also observed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
