Reacting in real-time to production contingencies in a capacitated flexible cell

Abstract

We present a PC-based procedure for the real-time revision of production and inventory schedules in a capacitated flexible manufacturing cell, so as to counter the impact of production contingencies (defined as unanticipated disturbances that force a revision in the schedule). In capacity constrained production systems, a reallocation of capacity among the various manufactured items coupled with a backordering of the end-item must occur to counter such contingencies. However, by taking advantage of existing and planned inventories in the current schedule generated using Materials Requirement Planning (MRP), it is possible to delay the onset of these end-item backorders, and provide the scheduler with additional time to explore other corrective measures such as using overtime and sub-contracting, before resorting to backordering. The objectives in our problem are to delay the end-item backorders as far as possible, minimize the magnitude of these backorders, and maximize the savings in inventory costs that may result from these backorders. The algorithm is capable of handling problems of large size and is computationally efficient. The implementation of the algorithm is extremely simple and requires only three items of data input in an open format as prompted by the system.