Chatter prediction using dynamic simulation

Prediction of the vibratory behaviour in machining is widely studied in the literature. The most common techniques of simulation consist in the linearization of the machining process; they lead to the traditional form known as of 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 (modelling of the cutting forces, modelling 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 mechanistic model of cutting forces with the generation of the machined surface using an "eraser of matter"approach. The computer program discretises the geometry in elementary discs along Z axis (model 2 D ½) and the dynamics is modelled using its modal characteristics. 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 or maximum vibration level). Copyright © 2007 Praise Worthy Prize - All rights reserved.

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