Cooling Potential of Heat Pipes and Heat Exchangers within a Machine Tool Spindle

Heat losses of the motor and bearings lead to thermal loads on motor spindles and thus to machining inaccuracies, varying dynamic spindle stiffness and decreasing bearing life. The herein introduced novel cooling approach uses heat pipes and heat exchangers to dissipate heat from the shaft through air convection to decrease thermally induced influences on the spindle. This paper illustrates the implementation of the heat transfer devices into a spindle system and results of measurements on a prototype spindle. Finally, the concept's potential for reducing spindle displacement, system temperatures and the time to reach a thermally stable state is shown.