Integrated model of quality inspection, preventive maintenance and buffer stock in an imperfect production system

Abstract In this study, the influence of a quality inspection policy on an imperfect production system in which a percentage of the produced items is inspected is modelled. The inspection policy is imperfect, permitting type I and type II errors. Items are shipped for sale with a free minimal repair warranty policy. After each production cycle, preventive maintenance is performed. In case of failure in the production process before the cycle’s end, a minimal repair is indicated. A buffer stock is established to meet demand while preventive maintenance is performed. We also considered that defective items detected on inspection are sent for reworking. The model is formulated with the objective of minimizing the total cost expected per item while considering an average outgoing quality constraint. Subsequently, we present a numerical experiment to illustrate the proposed model. The results indicate that the probability of type I and type II inspection errors has a significant impact on optimal production and the percentage of items inspected.