Modelling thermomechanical behaviour of multi-axis machine tools

This paper describes a method to measure and model the thermally induced positioning errors of multi-axis machines. These errors result from changes in temperature distribution of such a machine. To achieve a reduction of the machine's tool positioning errors a generally applicable model has been developed. First the temperature distribution of a machine tool is computed from a limited number of sensors. Using this calculated temperature distribution and a deformation model based on the machine's structural loop and rigid body kinematics the tool positioning error is computed. To validate the developed thermomechanical model a new measuring method based on three-dimensional length measurements has been used.