Modelling of friction conditions along rounded cutting edges

• Applicant: Professor Dr.-Ing. Berend Denkena
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 466817376

The friction in machining processes is currently not sufficiently understood, which means that there is still a need for further research. There is a lack of knowledge about the influence of the local thermomechanical load collective and in particular the local material condition on the local friction behaviour in the contact zone. One of the current main research areas is therefore the exact modelling of the friction behaviour as well as the provision of the necessary data sets. In spite of the continuous development of methods for friction coefficient determination and the numerous work in the field of friction modelling, the results derived from these methods are still inadequate. The main reason for this is that there are currently no analogy experiments, which fully map the characteristics of chip formation and the thermomechanical loads acting on it. Therefore, averaged values for temperature, relative velocity and normal stress are usually assumed along the contact surface, whereby the modelling is faulty. The resulting friction models, which are used especially in chip formation simulations, have a variance between the real and the simulated contact conditions, since the models were not set up under real cutting conditions. This represents a major obstacle to the successful further development of chip formation simulations. Our own preliminary work shows a possibility to determine the local stresses in the contact zone and to record the flow behaviour of the material. These data can be recorded at high cutting speeds during chip formation and thus represent the friction conditions under real cutting conditions. Based on these findings, a spatially resolved calculation of the coefficient of friction and a significant reduction of the experimental effort are possible. Therefore, valid data sets are to be generated under real machining conditions by combining suitable measurement methods and evaluation algorithms and physically based friction models are to be derived on this basis. The main objective of the planned research project is the development of a method to derive friction models for machining processes by means of high-speed chip formation analyses.

• DFG Programme: Research Grants
• Major Instrumentation: Thermokamera
• Instrumentation Group: 5430 Hochgeschwindigkeits-Kameras (ab 100 Bilder/Sek)