Fundamental Investigations on the frictional contact in the working zone in machining processes

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Machining processes are majorly influenced by frictional events in the contact area of the tool and the workpiece. The working zone is characterized by high deformation rates, contact pressures and temperatures. Therefore, the friction conditions of the chip formation process distinguish significantly from established friction tests. In this project the analysis of friction is supposed to be carried out under the terms of machining conditions with respect to mechanisms and their interactions as well as influences by process parameters. A special test setup that enables testing conditions similar to machining conditions is used for the investigation. In this test the workpiece is moved relatively to the tool so that the workpiece is plastically deformed. Both objects are made of materials commonly used for machining processes. The sliding velocity, the surface topology and the temperature determine the frictional contact and are investigated in this project. The test setup provides the ability to reach different temperatures at the same sliding velocity. Therefore, this setup superior to methods like the pin-on-disc-test.Another goal of this project is to achieve an improved and realistic friction model for the simulation of chip formation. Finite-Element-simulations of the chip formation made great progress over the last decade. In order to obtain realistic simulation results proper input data for the material and frictional behavior is needed. Especially the cutting normal force depends on the friction between the chip and the rake face and is often miscalculated in FE-simulations. Therefore, this project should provide a proper friction model to improve the simulation of process forces.