Forces, vibrations and roughness prediction in milling using dynamic simulation

Several methods to predict vibratory the behavior in machining are listed in the literature. Some of them consist in the linearization of the machining process; they lead to the traditional form known as the 'stability lobes'. This approach does not take into account some characteristics of the milling process (periodic variation of chip thickness, entries and exits of the tool), especially in finishing. Dynamic simulation of the process, based on three fundamental pillars (modeling of the cutting forces, modeling of the machined surface and prediction of the relative movements between the part and the tool), are more suitable in this case. The purpose of this article is to present a simulation tool that combines a model of cutting forces proposed in the literature by Engin and Altintas with the generation of the machined surface by a model 'eraser of matter'. The computer program discretizes the geometry in elementary discs along Z axis (2 D 1/2 model)and the dynamic is currently modeled as classical 'mass-s ing-damper' system. It predicts the cutting forces, the vibrations and the geometry of the machined surface. It is thus possible to give acceptable range for parameters such as spindle speed or depth of cut according to technological criteria (roughness after machining, maximum effort on the cutter, maximum vibration level).