Inherent thermal error compensation of machine tool structures with grated meneral casting

Thermal effects on machine tools from processing and the environment often lead to non-axis-parallel deformations of machine components. For ensuring precision machining under workshop-typical conditions, the article describes the modelling and simulation of a machine tool bed with layers of a different thermal expansion made by mineral casting. By reducing the surface warping the internal compensation within the machine controls will be significantly simplified. In order to obtain optimum graded structures, it's important to analyze the expansion behaviour of the heterogeneous material. For this purpose, a measurement method is presented which makes it possible to determine the expansion coefficient precisely.