Heat Flux in Cutting: Importance, Simulation and Validation

Abstract

The trends of machining difficult-to-machine materials and of dry machining or MQL lead to high temperatures in the cutting zone and increase the importance of thermal factors in the machining process. Besides amplified thermal tool loading and wear, the thermal fluxes affect the machining accuracy due to thermo-elastic deformations. Thus it is extremely important to know the magnitudes of these heat flows in order to assess the machining process heat and the tool wear and to develop compensation strategies against thermal tool center point (TCP) displacements. Based on the FE modeling of the cutting processes, the paper describes methods of determining the generated thermal energy and heat fluxes. Furthermore, new methods are presented how and in which partitions this heat flows into the workpiece, the tool and the chips. In order to validate the methods, 2D FE models are compared with temperature and force measurements carried out on a broaching test bed. The methods are applied on cutting examples which are investigated in the papers of Komanduri and Hou using analytical models. Thus, the simulation allows an assessment of the heat fluxes in real cutting processes in comparison with analytical and simplified numerical models.

Heat flux in metal cutting: Experiment, model, and comparative analysis

“…10 s), (ii) practically stabilizes with small residual oscillations at a certain level or demonstrates a slow growth, and (iii) decreases over a short period of time (approximately 5 s) after tool disengagement [10,13,14,15]. Other researchers [17,18,19] reported constant or near-constant heat flux behavior over the machining time. However, this flux behavior differs from the behavior observed during metal cutting, where the temperature in the primary, secondary and tertiary zones reaches its maximum value almost instantly [1].…”

“…This is the first hypothesis of flux behavior over time. But in the studies devoted to spatial distribution of heat flux [17,18] and in [19], the flux was considered to be constant over time. This is the second hypothesis shown in Fig.…”

“…25. (a) Three identified flux behaviors over process time: increasing [13,15], constant [17,18], decreasing (this study); (b) Calculated temperature at the control points for each of the three hypotheses.…”

“…Putz et al [17] developed a method to determine the generated thermal energy and heat fluxes partitioned among workpiece, tool, and chip using infrared thermal imaging. Though a new method based on retrieval of heat flux from generated heat energy was proposed, it was tested only for 2D geometrical models and linear heat transfer cases.…”

Transient Temperature Field Model of Wear Land on the Flank of End Mills: A Focus on Time-Varying Heat Intensity and Time-Varying Heat Distribution Ratio

“…Therefore, some studies have investigated the relationship between thermal number and heat distribution ratio. Heat value parameters were applied to establish a calculation method for heat distribution ratio under continuous cutting conditions by Putz et al [21]. Moreover, Putz et al [22] extended the same parameters to the calculation of the heat distribution ratio in an interrupted cutting process.…”