Joint optimization of inspection, maintenance, and spare ordering policy considering defective products loss

This paper proposes a joint inspection-based maintenance and spare ordering optimization policy that considers the problem of integrated inspection, preventive maintenance, ordering, quality control for four-state single-unit manufacturing system. When an inspection detects minor defect, second phase is initiated regular order placed. Product begins to deteriorate when system undergoes severe defect. To counter this, advanced replacement defective carried out at 7th inspection. If defect recognized prior Jth or if failure occurs, corrective executed. The timeliness depends on availability spare. We adopt two modes ordering: emergency order. Meanwhile, threshold level introduced determine whether preferred even already ordered but has not yet arrived. optimal formulated by minimizing expected cost per unit time. A simulation algorithm proposed obtain two-phase interval, interval. Results from several numerical examples demonstrate that, in terms time, our model superior some existing models.