Application of Plastic Boundary Layer Theory to Metal Machining

Abstract

In the metal machining operation, material is deformed at high rates in thin plastic zones. This paper explores the possibility that the features of such shear zones can be described by a theory for plastic boundary layers. The analysis draws on Oldroyd’s solution for the two-dimensional plastic flow of a Bingham solid over a flat knife. The way in which such a solution can be adapted to both the secondary and primary deformation zones in machining is described. A theoretical equation is derived that uses material properties to predict the tool-face pressure gradient along the contact length. An analysis for brass gives very good agreement between this approach and the experimental data for the tool-face pressure gradient obtained by Rowe and Wilcox.