The fatigue behavior of components made of quenched and tempered steel alloys is of elementary importance, especially in the automotive industry. To a great extent, the components’ fatigue strength is influenced by the surface integrity properties. For machined components, the generated surface is often exposed to the highest thermomechanical loads, potentially resulting in transformations of the subsurface microstructure and hardness as well as the residual stress state. While the measurement of the mechanical load using dynamometers is well established, in-process temperature measurements are challenging, especially for drilling processes due to the process kinematics and the difficult to access cutting zone. To access the impact of the thermomechanical load during the single-lip drilling process on the produced surface integrity, an in-process measurement was developed and applied for different cutting parameters. By using a two-color pyrometer for temperature measurements at the tool’s cutting edge in combination with a dynamometer for measuring the occurring force and torque, the influence of different cutting parameter variations on the thermomechanical impact on the bore surface are evaluated. By correlating force and temperature values with the resultant surface integrity, a range of process parameters can be determined in which the highest dynamic strength of the samples is expected. Thermally induced defects, such as the formation of white etching layers (WEL), can be avoided by the exact identification of critical parameter combinations whereas a mechanically induced microstructure refinement and the induction of residual compressive stresses in the subsurface zone is targeted. Further, eddy-current analysis as a non-destructive method for surface integrity evaluation is used for the characterization of the surface integrity properties.

Sustainability is an increasingly important trend, giving great potential in industrial production to save resources and energy. This paper presents fundamental research results on the reduction of cutting-tool consumption and saving on workpiece-material. For the basis of a new wear model, explicit knowledge of the thermo-mechanical loads and relative speeds between the tribological partners is of central importance. Therefore, a special open tribometer will be used to parameterize a friction model depending on relative speeds. Both, uncoated and coated tools are used. To reduce experimental effort, numerical simulations serve as an efficient representation of the cutting process. As a novelty in the project’s further course, both the experimentally determined tool temperatures and the friction conditions will be recorded in dependence on the tool wear, complemented by synchronized digitized wear images for validation purposes. The second work focuses on burnishing as a post-processing method for additively manufactured components. Compared to conventional machining, material and energy is saved and the workpieces’ surface integrity is improved, potentially increasing the components’ lifetime. Experimental tests are extended by finite element simulations, enabling investigations at different scales: At a workpiece model size of several millimeters, residual stresses are to be predicted; at a micrometer range, the surface smoothing is mapped.

The thermomechanical load on the workpiece surface during the machining process strongly influences its surface integrity and the resulting fatigue strength of the components. In single-lip drilling, the measurement of the mechanical load using dynamometers is well established, but the thermal interactions between the tool and the workpiece material in the surface area are difficult to determine with conventional test setups. In this paper, the development and implementation of an in-process measurement of the thermal load on the bore subsurface is presented. The experimental setup includes a two-color ratio pyrometer in combination with thermocouples, which enable temperature measurement on the tool’s cutting edge as well as in the bore subsurface. In combination, a force measurement dynamometer for measuring the occurring force and torque is used. Thus, the influence of different cutting parameter variations on the thermomechanical impact on the bore surface can be evaluated.

Für die Vorhersage des Werkzeugverschleißes sind neben den Kontaktnormalspannungen und den Relativgeschwindigkeiten die explizite Kenntnis des thermo-mechanischen Belastungskollektives, das im Wesentlichen durch die Reibungsverhältnisse zwischen den Tribopartnern beschrieben wird, von zentraler Bedeutung. Die vorliegende Studie befasst sich mit der Parametrierung eines von der Relativgeschwindigkeit abhängigen Reibungsmodells, welches im weiteren Projektverlauf einen Teil der Datenbasis für die Entwicklung eines Verschleißmodells bildet.   Of central importance for the prediction of tool wear, besides contact normal stresses and relative velocities, is the explicit knowledge of thermo-mechanical loads mainly described by the friction conditions between the tribological partners. The present study focuses on the parameterization of a friction model depending on the relative velocity, which subsequently will form part of the data basis for developing a wear model.

Die Verfahrenskombination aus Laserpilotieren und Einlippentiefbohren ist ein vielversprechender Ansatz, die Flexibilität bei Tiefbohrbearbeitungen signifikant zu steigern. Mithilfe des Lasersystems ist es dabei möglich, verschleißfrei Pilotbohrungen auf schrägen, gekrümmten oder sogar randschichtgehärteten Bauteilen zu erzeugen.