Dynamic loads and thermal errors on machine tools

Thermal effects on machine tools are one of the major influences on machine tool accuracy. In order to analyze the effects of thermal deformation, numerical analysis using FEM is a common procedure. The quality of the FE analysis largely depends on the accuracy of the boundary conditions. A common heat source is the friction in machine elements as guide ways, ball screws and bearings. The friction losses in these components generally depend on the loading. In this paper multibody dynamics is coupled with FEM to compute the dynamic loads and thermal errors on machine tools. Multibody dynamics system (MBS) is used to compute the loads which are used to derive the friction losses. These friction losses are then transferred to a thermomechanical FE model of the machine tool in order to calculate the thermal errors at the TCP (Tool Center Point).