The Effect of Prior Cutting Conditions on the Shear Mechanics of Orthogonal Machining

It has been proposed several times in the metal-cutting literature that the machining process is non-unique and that the instantaneous machining conditions depend on the prior machining conditions (e.g. depth of cut, rake angle etc.). To evaluate the validity of this concept, a series of experiments was conducted using a highly accurate CNC machining center. For these experiments, the machining conditions were changed during the course of an orthogonal cutting experiment in a repeatable manner and the measured forces compared as a function of prior history. Tests were conducted on several tempers of 1100 aluminum and commercial purity zinc to evaluate the effect of material properties on the machining response. It was found that the change in measured cutting forces which could be ascribed to prior machining history was less than 3 percent and that material properties, particularly work hardening response, had no discernible effect on the magnitude of the difference.

[1]  E. G. Thomsen,et al.  Observations on the Angle Relationships in Metal Cutting , 1959 .

[2]  E. Usui,et al.  Analytical Prediction of Three Dimensional Cutting Process—Part 2: Chip Formation and Cutting Force with Conventional Single-Point Tool , 1978 .

[3]  John S. Strenkowski,et al.  Finite element models of orthogonal cutting with application to single point diamond turning , 1988 .

[4]  R. Hill.  The mechanics of machining: A new approach , 1954 .

[5]  U. F. Kocks.  Laws for Work-Hardening and Low-Temperature Creep , 1976 .

[6]  E. Voce,et al.  The relationship between stress and strain for homogeneous deformations , 1948 .

[7]  Tom Childs,et al.  Computer-aided simulation and experimental studies of chip flow and tool wear in the turning of low alloy steels by cemented carbide tools , 1990 .

[8]  T. Shi,et al.  Slip-line solution for orthogonal cutting with a chip breaker and flank wear , 1991 .

[9]  Masami Masuko,et al.  Analytical Prediction of Three Dimensional Cutting Process—Part 1: Basic Cutting Model and Energy Approach , 1978 .

[10]  W. A. Backofen,et al.  Adiabatic instability in the orthogonal cutting of steel , 1972 .

[11]  David A. Stephenson,et al.  The mechanical behavior of zinc during machining , 1995 .

[12]  K. Osakada,et al.  Process Modeling of Orthogonal Cutting by the Rigid-Plastic Finite Element Method , 1984 .

[13]  R. N. Roth.  The range of permissible shear angles in orthogonal machining allowing for variable hydrostatic stress on the shear plane and variable friction angle along the rake face , 1975 .

[14]  P. Dewhurst.  On the non-uniqueness of the machining process , 1978, Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences.