Development of a numerical cutting model for understanding the chip formation in cryogenic machining

Abstract

The aim of this study is to develop a finite element model of metal cutting that includes fluid structure interaction. The proposed model is used to improve the physical comprehension of the chip formation during cryogenic assisted machining. This is performed based on the coupled-Eulerian-Lagrangian formulation. An algorithm is also developed to ensure heat exchange between the fluid and the structure. It also allows decoupling the mechanical and thermal effects induced by liquid nitrogen. The titanium alloy Ti17 is used as a work material, and uncoated tungsten carbide is used as a tool under dry and cryogenic conditions with cutting speeds of 50 m/min and 70 m/min and feeds of 0.1 mm/rev and 0.2 mm/rev. Simulation is validated by comparison with the experimental results. Standard deviations of both forces and chip thickness are low; they stay under 15% and 35% of the average value, respectively. The chip formation, the cutting force and the temperature are studied. It is shown that cryogenic machining has a significant effect on the chip formation and the temperature distribution in the cutting zone. A remarkable temperature reduction by up to 500 °C is observed at the tool rake face. However, the tool tip temperature slightly decreases with the application of liquid nitrogen when compared to dry machining.