Temperature characteristics of supply oil in an ultra-precision hydrostatic table are largely influenced by parameter setting in an oil cooler such as the location of reference sensor and cooling temperature. In this paper, influences of the parameter setting on the temperature variation in the hydrostatic table are experimentally analyzed to suggest the guidelines for practical application. In case of using temperature of inlet oil as a reference sensor in the oil cooler, temperature rise of the supply oil is smaller and thermal settling time is faster than that of using temperature of outlet oil as a reference sensor. The experimental results also show that temperatures of table, rail and return oil can be made almost same, and thermal settling time can be decreased by setting cooling temperature in the oil cooler to be lower than atmospheric temperature.
