Managing a deteriorating process in a batch production environment

When manufacturing processes have a tendency to deteriorate over time and begin producing defective products, there is always a trade-off between the cost and/or rework time that is associated with such defectives and the amount of time that is spent inspecting and restoring the process. Although a considerable amount of attention has been devoted to this trade-off as it is found in high-volume, repetitive manufacturing, we study it in a job shop environment. In particular, we study the way in which inter-job setups affect the inspection policy. After modeling the problem as one of maximizing the throughput of defective-free jobs, we describe a simple algorithm which identifies optimal inspection intervals.