Addressing the requirements of accuracy, reliability, and durability, Fischer developed a shaft cooling system for its motorized spindles. The complete shaft, including rotor and bearing inner rings, are cooled with water through a series of channels. This became possible by developing a special three-channel rotary joint that to supply the channels with water and offers the additional option of a regular rotary joint, i.e. sending coolant through the center of the shaft to the tool tip.

When major heat sources like the rotor and the bearings are cooled directly, tests show that up to 1kW of additional losses can be removed from the shaft of the spindle. Consequently, the warm-up time of the test spindle was reduced by 80%  and less heat migrated into the machine. Compared to a conventional cooling system, at the tool interface a temperature reduction of 25°C was achieved. These tests prove the point that the Fischer spindle does not heat up the tool.

Additionally, tests with rigidly preloaded bearing systems have also been very successful. Due to the reduction of the temperature differential between the inner and outer rings of the bearings, speed factors up to 2 million n×d_m [mm/min] and higher were achieved. The opportunity of eliminating the often critical floating bearing system greatly enhances reliability. The axial bearing displacement and the axial shaft growth are reduced, and therefore flexibly preloaded bearing systems are consequently less critical.

Fischer Precise has experienced a very positive influence on bearing life. However, statistically proven data will be obtained in one or two years in various production trials.