COMBINED EFFECTS OF FLANK AND CRATER WEAR ON CUTTING FORCE MODELING IN ORTHOGONAL MACHINING—PART I: MODEL DEVELOPMENT

Abstract

Progressive tool wear, mainly in the forms of flank and crater wear, occurs on the tool flank and rake faces, respectively. Cutting forces may increase or decrease depending on the combined contribution from the flank and/or crater wear. Quantitative understanding and prediction of cutting forces under both tool flank and crater wear conditions is of importance to cutting process thermal modeling, tool life estimation, chatter prediction, and tool condition monitoring purposes. Unfortunately, there is no adequately documented work to analytically study the combined effects of both flank and crater wear on cutting forces and investigate the associated underlying machining physics. In this study, a slip-line field based force modeling approach is proposed to capture the worn tool cutting mechanism under the combined effects of both flank and crater wear in orthogonal cutting. The proposed slip-line field and the associated hodograph are introduced, and the slip-line models for the primary shear zone, the flank wear land and each part of the secondary shear zone are discussed in detail. The model implementation procedure is also proposed in terms of the hodograph geometric relationship and the force and moment equilibrium in order to predict cutting forces of interest.