New Developments in the Theory of the Metal-Cutting Process: Part I. The Ploughing Process in Metal Cutting

TLDR

Ploughing, caused by the finite sharpness of the cutting edge, is a key factor in metal‑cutting mechanics, influencing tool forces, built‑up edge, chip curling, and residual stresses. The study introduces the ploughing force concept to construct a more complete force diagram that distinguishes ploughing from chip‑tool interface forces. The authors derive the force diagram by modeling the ploughing force at the extreme cutting edge and separating it from the chip‑tool interface force. Experimental validation confirms the force diagram components, and the study determines the true chip‑tool interface friction coefficient, resolving its apparent dependence on rake angle.

Abstract

Revelation of the significance of “ploughing” in the metal-cutting process, which occurs because of the finite sharpness of the cutting edge, leads to a better understanding of the mechanics of the metal-cutting process. The concept of the ploughing force on the extreme cutting edge allows the development of a more complete force diagram which separates the ploughing force from the chip-tool interface force. Components of this more detailed force diagram have been verified experimentally. In terms of the new force diagram the real value of the coefficient of friction on the chip-tool interface has been found and the paradox of variation of the coefficient of friction with variation of rake angle explained. The paper also contributes to a better understanding of such events as the effect of cutting velocity upon tool forces, built-up edge, chip curling, and residual stresses in the work surfaces.