Abstract: A modeling method is proposed to predict the spindle thermal error with high accuracy, in which the mechanism of temperature field and thermal deformation in spindle is analyzed and the preliminary theoretical model is modified by thermal basic characteristics tests to obtain the final model. The preliminary theoretical model of temperature field and thermal deformation is built via mechanism analysis which is based on the size of the spindle and bearings’ parameters. In different initial temperature two thermal basic characteristics tests are conducted, in which temperature at the front and rear bearings and the front end-cover of the spindle is measured by temperature sensors and the spindle axial thermal deformation is measured by a displacement sensor. The tests’ result is used to modify the preliminary theoretical model to get the final model. An experiment on an NC lathe’s spindle is conducted to validate the modeling method. The results show that the new modeling method is precise in predicting spindle’s temperature field and thermal deformation not only during the heating process but also the cooling process. So the new modeling method is suitable for different kinds of machine tools in predicting spindle thermal deformation.

Key words: machine tool;spindle;temperature field;thermal deformation;mechanism analysis;thermal basic characteristics test