Investigation of thermally induced TCP-displacement under load of the machine axes in different areas

Abstract

As known, thermally induced displacements can cause up to 75% of workpiece errors. To investigate the structural deformation of the machine, Integral Deformation Sensors (IDS) were developed. With these sensors the deformation of machine parts can be measured, and the resulting tool center point (TPC) displacement can be analyzed and predicted by a mathematical model of the machine. This paper focuses on the analysis and prediction of the machine deviation under load of the machine axes in different areas.As machine tools can hardly be built completely thermically symmetrical, the influence differs, if an axis is only moved in a certain area or along the whole way that the axis can be moved. In this paper, the impact of this fact on thermally induced displacement is investigated in several tests. By doing so, the component deformation is analyzed by IDS. Furthermore, the TCP dislocation is analyzed by modelling it simultaneously by IDS and measuring and the actual displacement using 3D probe. The results show not only the measured displacement of the TCP but also the correct prediction based on the data gathered from the IDS and therefore prove that the compensation method based on the IDS can increase the machines robustness against thermal issues.