An Analytical Modeling Of Temperature-field In Cutting Zone And Its Experimental Investigation For Hard Cutting

As well-known as the cutting temperature and its distribution in the cutting zone are a critical factor that significantly affects tool life and degrades part accuracy during hard cutting processes. However, issues surrounding their modeling and experimental validation in the immediate cutting zone still remain an unresolved issue. A major impediment is the unavailability of adequate temperature measurement methods with sufficient temporal and spatial resolution to measure actual temperatures and validate predictive models.From the standpoint of the common issues with the limitations that existed in the cutting temperature models and experimental measurements, In this paper, a model for the dry orthogonal cutting process with thermo-mechanical coupling effects is proposed to predict cutting temperature distribution as well as the relevance parameters in the cutting zone. In this model, to model the non-uniform distribution of the chip flow velocity along the tool/chip interface, a unique stagnant region within the secondary shear zone was added into the slip-line field. Based on Komanduri and Hou’s approach, a modified thermal assumption for the temperature rise in the cutting tool that considers the fact heat transfer occurs from both the rake and flank faces was also proposed.Cutting temperature distributions were measured by Micro-scale Thin Film Thermocouples (TFTCs) embedded into PCBN cutting inserts in the immediate vicinity of the tool-chip interface. Using these measurements and predictions during hard turning, the feasibility and prediction accuracy of the model is verified by experimental measurements through TFTC arrays embedded into the PCBN tooling. The experimental verification is performed under hard turning conditions. It has been shown that the predictions of the proposed model are in very close agreement with the experimentally measured results including the cutting forces, chip thickness and cutting temperature distributions on the rake and flank faces in the cutting zone.Numerous detailed analysis of the thermo-mechanical coupling mechanisms and some of the unresolved issues in the hard turning processes have been offered with the two contents that combined by experiment measurements and modeling predictions. Based on the predictions of the analytical approach, the modeling results have also provided an essential understanding on steady-state thermo-mechanical effects, i.e., the influences among in cutting temperatures in the cutting interfaces, stress distributions at the tool/chip and work/tool interfaces as well as of the nature of the chip flow velocity along the rake face of the cutting tool. It has been shown that the temperature changes in the cutting zone depend on the heat resource’s location in the chip and the thermal transfer rate from the heat generation zone to the cutting tool.Moreover, in current work, a combined investigation on dynamic as well as chip morphology and formation process analyses were performed based on the cutting temperature and cutting force variations in the cutting zone. It became evident that the cyclically changes in the material flow stress and the adiabatic shearing bands generated greatly affect not only the chip formation morphology but also the cutting temperature field distributions in the cutting zone of the cutting insert.Overall, The research achievements can be used to perform more fundamental investigations for metal removal machining mechanism and for widespread applications such as cutting parameters optimization and machining process monitoring etc. The proposed approach also possesses the abilities that used to advance the metal removal processing research evolution forward.