Process Control for Three Quality Classes and Three Repair Actions

Abstract In this paper a production process with a uni-variate quality characteristic is considered where the output is classified in three quality classes: good, marginal and bad. The process is subject to quality deterioration and, therefore, it is periodically monitored and according to the observed result a decision for one of four courses of action is made. The control procedure is represented by means of a GERT network and subsequently analysed using the so-called W -functions. Finally, the behaviour of the control scheme is investigated by some numerical examples.