FE analysis of the effects of process representations on the prediction of residual stresses and chip morphology in the down-milling of Ti6Al4V

Abstract

Abstract In part II of these two-part papers, the effects of four FEM representations of the milling process on the prediction of chip morphology and residual stresses (RS) are investigated. Part II focuses on the milling of conventional uncut chip thickness h with finite cutting edge radius and flank wear, while part I of these two-part papers has reported on the results in the case of milling small uncut chip thickness in the micrometre range with finite cutting edge radius. Two geometric models of the flank-wear land composed of flat and curved wear land are proposed and assessed. The four process representations are: i) orthogonal cutting with flat wear land and with the mean uncut chip thickness h ¯; ii) orthogonal cutting with flat wear land and with variable h, which characterises the down-milling process and which is imposed on a flat surface of the final workpiece; iii) modelling the true kinematics of the down milling process with flat wear land and iv) modelling the true kinematics of the down milling process with curved wear land. They are designated as Cte-h, Var-h, True-h and True-h*. The effectiveness of these representations is assessed when milling Ti6Al4V with a flank-wear land of VB = 200µm.