Relationship Between Tool Temperature Distribution and Stagnation Point Behavior for Different Process Factors in Machining Operations

Abstract

Metal cutting is physically defined by a tool separating a chip by developing a stagnation point after the work material has passed a shear plane. This distinguishes the method group metal cutting or machining from shearing and wedging processes. The development of the stagnation point is central to the functioning of a metal cutting process. The stagnation point and its behavior has a great influence on the different load conditions of the tool as it controls both the temperature distribution and the mechanical load distribution around the tool’s edge-line. This publication shows that there is a temperature drop at the stagnation point where the shear stress changes sign, which means that the shear stress at this point assumes the value zero. Furthermore, it is demonstrated that there is a correlation between the position of the temperature dip, its size and the selected cutting data as well as tool geometry and current work material. The knowledge of the interaction between the position of the stagnation point and the tool coating type in combination with the tool’s micro- and macro-geometry will be of importance for the development of high-performance tools optimized for different machining applications.