The performance factor (see also performance rate) is a measure for losses due to deviations from the planned time per part, losses due to short downtimes (i.e. downtimes which do not affect the availability) and idle speeds. The performance factor (e.g. indicated in parts per hour) is used for calculating the Overall Equipment Effectiveness (OEE) and defined according to eq. 1, it is defined as follows:
It is to be considered that the performance factor may only be calculated referring to the runtime, not the operation time. While the actual performance is measurable in most cases, in operational practice it tends to be difficult to determine a target performance as standard value.
If the machine manufacturer did not give any indications or if these are not realistic, it is recommended to use the “self-demonstrated time per piece” concept for determining the target performance. In this concept, production speeds of products from the past are compared and the highest production speed is defined as target performance with a performance factor of 100 percent. However, this performance factor should not be used for production program planning. Factor 1 represent a maximum value which regularly could not be achieved.
With machines which produce only one or a couple of products, the performance factor calculation is simple. However, if numerous different products are produced on one machine, the effort to determine a target time might be very high.
Modern software with process data and time registration makes it possible to capture and visualize the performance factor (performance rate) .