Nonlinear dynamics of milling processes

In this article, dynamics and stability of milling operations with cylindri cal end mills are investigated. A unified-mechanics-based model: which allo ws for both regenerative effects and loss-of-contact. effects, is presented for study of partial-immersion, high-immersion and slotting operations. Re duced-order models that can be used for certain milling operations such as full-immersion operations and finishing cuts are also presented. On the bas is of these models, the loss of stability of periodic motions of the workpi ece-tool system is assessed by using Poincare sections and the numerical pr edictions of stable and unstable motions are found to correlate well with t he corresponding experimental observations. Bifurcations experienced by per iodic motions of the workpiece-tool system with respect to quasi-static var iation of parameters such as axial depth of cut are examined and discussed. For partial-immersion operations, consideration of both time-delay effects and loss-of-contact effects is shown to have a significant influence on th e structure of the stability boundaries in the space of spindle speed and a xial depth of cut. The sensitivity of system dynamics to multiple-regenerat ive effects, mode-coupling effects and feed rate is also discussed.