AN INVESTIGATION OF THE USE OF HEAT PIPES FOR MACHINE-TOOL SPINDLE BEARING COOLING

The results of an experimental investigation into the practicality of using a heat pipe installed in the spindle of a milling machine to rem ove the heat produced in the spindle bearings which is capable of caus ing thermal distortion and cutting error are presented in the paper. M easurements of the variation of bearing temperature with time are repo rted at four different spindle speeds when there was no heat pipe inst alled, when the heat pipe was cooled by air and when the heat pipe was cooled by an ice/water mixture. Analysis of the results by a simple h eat transfer model indicates that the particular heat pipe used was ca pable of removing up to 160 W with a corresponding 50% reduction in th e rise of the bearing temperature above the temperature of the surroun ding air at steady operating conditions.