Thermal error compensation of rotary axes and main spindles using cooling power as input parameter

Thermal errors of machine tools are one of the main contributors for geometrical inaccuracies of machined workpieces. In this paper, research work is presented compensating thermal errors induced by moving the rotary and swiveling axis unit of a five axis machine tool as well as running the main spindle. The compensation approach is based on a dynamic gray box model consisting of a system of differential equations. Input parameters related to the generated heat are investigated. The best relation between the arising thermal location errors and model input parameter is found for the cooling power of the machine tool axes and the main spindle. Based on measurements it is shown that all dominant thermal location errors can be significantly reduced.