Volumetric thermo-elastic machine tool behavior

This paper focusses on the volumetric thermo-elastic machine tool behavior. In particular environmental influences and internal heat sources like linear axes lead to inhomogeneous temperature distributions within the machine structure and results in a positional dependency of tool-center-point (TCP) deviations. Therefore a measuring method using tracking interferometers to characterize the volumetric thermo-elastic machine tool behavior is discussed. The presented results of volumetric deviations due to axis loads expose, that a volumetric view is indispensable. It could be shown, that straightness error motions as well as some rotational error motions seem to be not influenced by thermally induced deviations due to axis loads. While the dependencies between input power of the different motors and the positional error motions can be described by a linear function, rotational error motions and especially squareness errors show large nonlinearities. In a next step the measurement method will be used to develop a control-internal correction algorithm for volumetric thermo-elastic TCP deviations. The main focus will be on the physical–mathematical description of the relationship between input power and the resulting error motions as well as their time-dependent description by delay elements.