Spiring, Fred A. (1989, ASQC) University of Western Ontario, London, Ontario, Canada
There are processes where variation due to assignable cause occurs and is tolerated. This group encompasses those processes included in the category of Toolwear. The traditional toolwear problem involves a tool or die that is subject to deterioration over its lifecycle. From a functional point of view the tool generally performs well, but any variability in the output is due to the predictable deterioration of the tool as well as the natural variation in the process. An application of the process capability index, Cpm, is proposed that results in a numerical measure of the actual process capability associated with the process. The application provides statistical methodology for a problem that has received little or no attention in terms of statistical decision making.