Spindle Running Time
The spindle running time is the operating time of the work spindle in the machine tool. The running time indicates how many hours the spindle has turned during machining, similar to the mileage of a car. This determines the value of the spindle when it is sold.
The maintenance intervals are based on the running time, since, in contrast to the duty cycle, they indicate the actual load period of the spindle. In modern machines, the running time is automatically captured and recorded for evaluation. In production engineering, the running time can be set in comparison to the duty cycle in order to describe the productivity of the machine. Thus, with a 200h operating time, a running time of 100h is rather unproductive compared to a running time of 165h. In the first case, this results in an average spindle running time of 50%, in the second case an average running time of 82.5%. Nowadays, spindle running times of up to 90% of the operating times are possible in modern machines. An improvement of the spindle running time compared to the operating time can be achieved by automatic tool and workpiece changes as opposed to manual changes. This shortens the setup time. Programming is also very important for numerically controlled machines. External programming shortens the programming time at the machine which can be reduced to the approach of reference points. This increases the overall efficiency of the machine tool.
Source: Spindellaufzeit, 31 March 2007, https://de.wikipedia.org/wiki/Spindellaufzeit, 19 May 2008