Local damping modeling for simulation and optimization of the dynamic behavior of machine tools

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The performance and operating accuracy of machine tools is mainly determined by their dynamic behavior. Unbalanced dynamic properties of machine tools in interaction with process forces can result in unwanted vibrations whose consequences can be insufficient processing results, increased tool wear as well as damages to the machine tool. To avoid these effects while improving the performance of machine tools, a comprehensive optimization of the dynamic behavior is required in the development phase. Therefore, appropriate models for the various influencing factors are necessary. State of the art the mass- and stiffness properties can be simulated with sufficient accuracy, whereas often no appropriate models and parameters are available for the different damping effects in machine tools. In order to reduce this deficit, the research group "Damping effects in machine tools" is being funded by the German Research Foundation. Within the subproject "simulation of damping effects in the whole machine tool structure" at the Institute for Machine Tools and Industrial Management (iwb) a mechatronic basic structure of a machine tool was investigated and methods were developed to identify and to parametrize damping models for the various dissipation sources. Based on these results a modeling approach was developed to consider the various influencing factors, such as mass and stiffness properties, linear damping, friction, control and motion in the simulation and to predict their influences on the dynamic behavior with high accuracy. This opens up new possibilities for a comprehensive optimization of the dynamic behavior of machine tools. In this project, the achieved results and methods of the research group FOR 1087 are transferred to industry and used there to optimize the dynamic behavior of a machining center of the application partner. First, a mechatronic basic structure is investigated to transfer the methods for the identification of damping and friction models, for the consideration of variations and uncertainties in the simulation and for the modeling of the various influencing factors in a machine tool structure to industry. Based on the mechatronic structure the transition will be completed on the entire machine tool to identify and analyze further relevant dissipation sources. By using these insights and the results of the occurring uncertainties in the machine tool a comprehensive optimization considering the various influencing factors will be performed. The optimization is carried out with regard to the positioning accuracy and the dynamic compliance at the tool center point. The procedure includes the identification of optimization potential, the determination of improvement measures and the prototypical implementation and evaluation of the measures. From the obtained results, a generally applicable approach for a comprehensive optimization of the dynamic behavior of machine tools will be developed.