Mehrskalenmodellierung der thermomechanischen Werkzeugbelastung beim Trockenwälzfräsen

• Multiscale modeling of the thermomechanical tool load in dry gear hobbing

Troß, Nico; Bergs, Thomas (Thesis advisor); Karpuschewski, Bernhard (Thesis advisor)

Aachen : Apprimus Verlag (2023)
Book, Dissertation / PhD Thesis

In: Ergebnisse aus der Produktionstechnik 17/2023
Page(s)/Article-Nr.: 1 Online-Ressource : Illustrationen, Diagramme

Dissertation, RWTH Aachen University, 2023

Abstract

Gear hobbing is one of the most applied technologies for the manufacturing of external gears. Geometric process characteristics are often used for systematic tool and process design in gear hobbing. However, neither the physical influences of the material, nor the varying load during the hobbing process are considered by these characteristics. In particular, there is a lack of models to describe the thermal load of the tool. In this work, a multiscale model was developed, which combines process and chip characteristics with thermomechanical load and state variables on the basis of numerical FE-calculations. For this purpose, the thermomechanical load was first analyzed on the microscale in the linear orthogonal cut by means of 2D-FE-simulations. The cutting speed, the chip thickness, the working rake angle and the cutting edge radius were varied. Based on the FE-simulation results, analytical models for the approximation of the cutting and thrust force as well as temperature characteristics were derived and calibrated. The model equations were then scaled to the hobbing process. For this purpose, the temporally and spatially resolved chip and process parameters were first determined by means of a plane-based penetration calculation. These serve as input variables for the calculation of the cutting and thrust force as well as the temperature distribution on the rake face. The multiscale model was validated on the one hand by means of torque measurements in the fly-cutting trial and on the other hand by comparing the rake face temperature with 3D-FE-simulations. The multiscale model was analyzed with regard to an evaluation of the tool wear and the wear prediction of PM-HSS S390 tools. For this purpose, a comparison was made between the experimentally observed wear behavior and the calculated wear. Finally, the geometrical independence from the gear and tool geometry as well as the practical application of the model for systematic process and tool design was demonstrated using an alternative gear case. The model allows an application-oriented as well as computationally and time-efficient determination of the thermomechanical load collective of the tool during hobbing for different process designs with geometric independence. Knowledge of the prevailing load collective assists in the interpretation and description of the resulting wear mechanisms and appearances. A better understanding of the tool load and the resulting tool wear supports the knowledge-based design of tool and process and consequently enables process optimization.