A study of thermal behavior of the machine tool spindle

Abstract

The performances of high speed machine tools depend not only on the speed, power, torque, dynamic and static stiffness, but also on the thermal behavior of the spindle. These parameters directly affect the productivity and quality of machining operations. This paper presents a 3D FE thermal model, which was based on the thermo-mechanical bearing model and the numerical model of the spindle. Based on thermo-mechanical analysis of bearings with angular contact, generated heat and thermal contact resistance (TCR) are determined for each position of the ball. To provide the most accurate analysis possible in determining TCR, bearings are divided into several zones based on the geometry of their cross-section. The aforementioned constraints have been applied to the 3D FEM model which allowed for establishing temperature field distribution, and spindle thermal balance. In order to prove the efficacy of the proposed model, experimental measurements of spindle and bearing temperatures were done by using thermocouples and thermal imager.