The quality factor (also called quality rate, quality degree QG) is the ration of the yield to the produced goods and a measure for the loss due to defect parts which have to be reworked. The quality factor is used for calculating the Overall Equipment Effectiveness (OEE) and defined according to eq. 1 as follows:
Scrapping and reworking of defect parts are considered as quality losses. Momentarily present defect parts can easily be corrected by re-setting the machine. If such defects parts are repeatedly produced over a longer period, the indication of the error source identification tends to be more difficult.
Modern software with process data and time registration makes it possible to capture and visualize the quality factor (quality degree).