A treatise on material characterization in the metal cutting process. Part1: A novel approach and experimental verification

Everyday practice of cutting process planning requires reliable cutting for ce estimates, which currently can be obtained only from process-dependent m achinability databases. The greatest obstacle to develop a more basic, effi cient approach is a lack of understanding of material behavior under unique deformation conditions of cutting. Since metal cutting involves the physic al separation of the chip from the rest of the workpiece, this paper define s the metal cutting process as the purposeful fracture of workpiece materia l. Part one of this two-part paper presents a novel approach of characteriz ing the resistance of workpiece material to cutting. It is shown that the s train at fracture is the most general material behavior characteristic. The experimental results show that the strain at fracture measured in incremen tal compression is consistent with that measured in orthogonal cutting when all deformation variables are properly accounted for and that, contrary to the results obtained using other kinds of material characteristics, the re sistance to cutting of workpiece material in orthogonal cutting is not affe cted by high strains, strain rates and temperatures occurring in the cuttin g process. (C) 1999 Elsevier Science S.A. All rights reserved.