Dynamical behaviour of machine tools during friction stir welding

Friction stir welding (FSW) is a promising joining technology that is quickly becoming the preferred joining process for a wide range of applications. Because of their high static values, the process forces occurring during FSW still are a major factor concerning the development or the choice of friction stir welding machines. However, until now, the vast majority of research projects only consider the static force components or the maximum loads that occur during a given welding operation. But, like during turning or milling, the tool does generate oscillating process forces that induce vibrations into the machine structure and should not be neglected. Thus, the key aspect of this work is the comprehensive characterization of the dynamical nature of the process forces and their effect on the machine structure. These results are then used for the development of a process force model and the design of a machine model to simulate the response to these loads. These two models are combined in one simulation environment and interact with each other to predict the process stability for a certain combination of process parameters and machine.