Research on thermal stiffness of machine tool spindle bearing under different initial preload and speed based on FBG sensors

As a key parameter, stiffness determines the dynamic characteristics of both bearing and spindle unit. However, interactions between speed, initial preload, cutting force caused by thermal expansion unit components alter during running process. Aiming to carry out real-time online monitoring their effect on machine tool stiffness, fiber Bragg grating (FBG) sensors network was proposed. Further, effects were considered under various axial loads, combined axial, specific radial load study temperature increase, thermally induced stiffness. The results have shown that decreases with increase speed. Moreover, an optimal preload can be selected respect speed maximize Finally, additionally pre-tightened bearing.