Influence of cutting tool coating on rake and flank face temperatures by operando pyrometric temperature measurement during orthogonal turning of AISI 316L

The thermal loads in the chip formation zone are one of the most fundamental measurable process values determining tool wear and the surface integrity of the workpiece in metal cutting processes. Due to the limited accessibility and high temperature gradients within the contact zone, the high-resolution measurement of the temperature distribution still is a major challenge. Therefore, this paper presents a novel method for the operando measurement of rake and flank face temperatures during orthogonal turning of AISI 316L, that allows a high spatial resolution. The measurement results thus obtained are used for technological analyses as well as parameterization and validation of Finite-Element chip formation models. The influences of the cutting speed as well as different PVD coatings (TiN and Ti 0.50 Al 0.50 N) on the tool's temperatures were investigated. Results showed that the lowest temperature was measured using Ti 0.50 Al 0.50 N-coated tools, whereas the highest temperatures obtained for uncoated tools. As part of the simulation, different flow stress models as well as friction models were implemented. Regarding the simulated process forces and tool temperatures, the best prediction quality was reached using flow stress model with implemented damage criterion, considering chip segmentation in combination with relative speed and temperature dependent friction models.