Mechanics of Metal Cutting for a Material of Variable Flow Stress

Abstract

A new analysis is presented in which the variable flow stress property of the work material is taken into account. It is shown that changes in the so-called angle of tool-chip interface friction can result from changes in the shear zone mechanism and, for example, the paradoxical behavior observed when cutting with carbon tetrachloride as a “lubricant” can be accounted for in this way. It is concluded that if actual predictions are to be made about the cutting process, i.e., without first making cutting tests, then the angle of tool-chip interface friction cannot be accepted as given information. The analysis is extended to cutting with a variable depth of cut, and in agreement with experiment it is predicted that, with all other cutting conditions the same, the cutting force will be less for an increasing depth of cut than for a decreasing depth of cut.