| Abstract: | The rotational performance of a machine tool spindle has a direct influence upon both the surface finish and geometric shape of the finished workpiece. The variation of preload affects the stiffness of the spindle and the temperature of the bearing, which are also important factors in spindle motion. Although the large preload and stiffness will probably increase the stability of the spindle, the high temperature of the bearing will decrease the processing accuracy and damage the bearing. Contrarily, if the preload is not large enough, the error in the running spindle will increase, which represents lower precision. Therefore, the preload cannot be too large or too small, resulting in the compromising of these factors. In this study, the effect of the preload on the roundness accuracy has been examined at the different cutting conditions through the developments of measurement system of preload, temperature and roundness accuracy. The step-by-step data analysis procedure has also been developed to get the spindle radial error motions from the measured data. Through measurements of spindle running accuracy, the optimal preload was determined at the different cutting conditions. |
