Active coolant strategy for thermal balance control of motorized spindle unit

For the precision machining activity, the accuracy of motorized spindle unit can generally be influenced by ambient heat convection and spindle heat generations. This paper develops an active coolant strategy for spindle thermal balance control, to dissipate accurately disturbing heat transfers above. Analytical relationship among spindle internal heat generation, external heat convection and coolant heat dissipation is established. This modeling illustrates that spindle thermal errors can be actively corrected by the real time monitoring - decision making - eliminating method onto spindle structural temperature. Then this active coolant strategy is realized by a developing application of differentiated multi-loops bath recirculation system. Consequently, based on a workshop with about 3.5 °C ambient temperature time variance, advantages of the active coolant strategy are experimentally verified: Compared with previous strategy, the proposed strategy is more advantageous in aspects of spindle structural heat exchange and thermal error corrections.