Pressure-Induced Critical Influences on Workpiece-Tool Thermal Interaction in High Speed Dry Machining of Titanium

摘要

Cutting tools are subject to extreme thermal and mechanical loads duringoperation. The state of loading is intensified in dry cutting environmentespecially when cutting the so called hard-to-cut-materials. Although, theeffect of mechanical loads on tool failure have been extensively studied,detailed studies on the effect of thermal loads on the deterioration of thecutting tool are rather scarce. In this paper we study failure of coatedcarbide tools due to thermal loading. The study emphasizes the role assumed bythe thermo-physical properties of the tool material in enhancing or preventingmass attrition of the cutting elements within the tool. It is shown that withina comprehensive view of the nature of conduction in the tool zone, thermalconduction is not solely affected by temperature. Rather it is a function ofthe so called thermodynamic forces. These are the stress, the strain, strainrate, rate of temperature rise, and the temperature gradient. Although thatwithin such consideration description of thermal conduction is non-linear, itis beneficial to employ such a form because it facilitates a full mechanisticunderstanding of thermal activation of tool wear.