The spindle run-time defines the operating time of the working spindle in the machine tool. The run-time is the number of hours for which the spindle has rotated within the course of processing, similar to the mileage of a car. This determines the value of the spindle when sold.
The servicing intervals are based on the run-time as this provides the time for which the spindle has actually been stressed, in contrast to the switch-on time. In modern machines the run-time is automatically logged and recorded for evaluation. In production engineering the run-time can be compared with the switch-on time in order to describe the productivity of the machine. For example with a switch-on time of 200h, a run-time of 100h is rather unproductive compared to a run-time of 165h. In the first case, there is a percentage spindle run-time of 50% and in the second case of 82.5%. Nowadays, modern machine spindle run-times of up to 90% of the switch-on time are possible.
An improvement in the spindle run-time in comparison to the switch-on time can be achieved by automatic tool and workpiece changing in contrast to manual changing. This shortens the equipping time. Furthermore, with numerically controlled machines the programming is critical. External programming shortens the programming time on the machine, which can reduce the reference point runs. As a whole, this increases the efficiency of the machine tool. [WIKI08e]