Due date control in order-driven FAB with high priority orders

Presented in this paper is a dispatching rule to achieve the on-time delivery for an order-driven FAB involving high priority orders. We classify orders into two groups; regular orders (RO), high priority orders (HPO). HPO lots have shorter cycle times, tighter target due date and higher margins than RO lots. The proposed rule introduces the concept of reservation for HPO lots, which means the provisional allocation of capacity to meet the on-time delivery of HPO lots. Since the rule considers the due date of HPO lots first, RO lots might be tardy. To minimize the tardiness of RO lots, the proposed rule considers tool utilization as well as on-time delivery of HPO lots. We developed a simulation model based on MIMAC6, and conducted experimentations with MOZART^®. The experimentation results show that the proposed dispatching rule can achieve the on-time delivery of HPO lots with the minimum tardiness of RO lots.