Thermal Growth of Motor Spindle Units

Abstract

The paper deals with strategies for numerical compensation of thermo-mechanical deformation of machine tool spindles and the TCP, respectively. Methods for digital modelling and simulating the temperatures and thermo-elastic deformation are presented. This is done by considering the geometry, material data, drive signals and temperature values. The topic of compensating thermo-elastic effects in spindle units is an important topic in manufacturing. Analytical equation and function block methods for measuring and predicting thermal spindle growth are compared. The heat flow model converts variable spindle load, speed, coolant and ambient temperature into local temperatures followed by elastic deformations of the spindle unit. The simulation results were verified for different types of motor spindles by experiments on a spindle test rig at SPL GmbH. A thermal stiffness value [W/µm] is characterized by the energy losses of the spindle, which result in thermal growth. Different strategies for digital reduction of a thermal spindle growth were developed.