Most products have multiple characteristics, and customers accept products whenever all process capabilities of each characteristic satisfy preset specifications. Obviously, univariate process capability indices cannot meet the requirements stated as above. And Chen et al. (2001) used point estimation to evaluate process capability, even though the method agrees with 100% tests. If the check is sampling, the process capability must consider sampling error. So the research constructs a measuring model of process capability to consider sampling error to evaluate process capability for a multi-process produce based on Cpk which was proposed by Kane (1986).
Journal of Information & Optimization Sciences 30(4), pp.843-853