The effects of non-linearity of dynamic cutting process upon self-excited chatter vibration (1st report) —Slip Line Analysis of Dynamic Cutting Process—

Abstract

The paper presents an analytical method which enables us to predict the dynamic cutting forces under chatter vibration by using the data of orthogonal, steady cutting test. For small amplitude of the vibration, an instant of the dynamic cutting can be regarded as the steady cutting of an equivalent tool rake angle which depends upon the inclination of the outer modulation of the vibration. When the amplitude exceeds a certain limit, however, the tool-chip contact length does not catch up with the variation of the uncut chip thickness, hence a non-steady chip forming process appears in place of the usual one of the straight shear plane. The slip line theory of plasticity is applied to this transition and the dynamic cutting forces are obtained. Dynamic cutting tests including wave generation, wave removal, and wave combined proved the forces predicted are in good agreement with the experimental results, which clearly show the non-linear variation with the uncut chip thickness. © 1989, The Japan Society for Precision Engineering. All rights reserved.