Ball screw unit precise modelling with dynamics of loads and moving heat sources taken into account

Abstract

This paper deals with the precision modelling of the ball screw unit’s thermal behaviour in the turning centre and its impact on the tool head positioning error. The error components along controllable axes X and Z are described in detail using an FE model integrating the changes in thermal and force loads and deformations occurring during the motion of the nut as a heat source. The impact of the nut work cycle on the thermal deformations of the ball screw and the displacements of the slideways and the screw points along both the axes and on carriage positioning precision is demonstrated.