Nonlinear techniques to characterize precharter and chatter vibrations in the machining of metals

In this paper we report on the use of Poincare sections, phase plane portra its and false nearest neighbor techniques to understand bifurcations in the lathe cutting of aluminum. The experiments presented here offer further ev idence of deterministic tool vibrations below the classical onset of chatte r. While classical chatter exhibits strong periodic content, these prechatt er dynamics exhibit both quasiperiodic and chaotic vibrations. The method o f false nearest neighbors predicts an embedding dimenion between 4 and G fo r prechatter cutting conditions while showing a random characteristic for n o-cutting running of the machine. A one-dimensional delay-differential equation model is presented which exhi bits some of the characteristics of the Poincare sections of the experiment al time series.