Operation due dates

J.J. Kanet and J.C. Hayya. Priority dispatching with operation due dates in a job shop. Journal of Operations Management, 2(3) 167-175, 1982. 

During normal operation of the copper plant, there are a number of regular maintenance jobs that need to be planned. They are included in the scheduling problem as additional jobs that have given release dates and due dates. These maintenance jobs can mostly be performed only when a unit is empty and not in use. The optimization approach finds the best location for each maintenance job with the least impact on production throughput and, furthermore, modifies the batch recipes such that there will be a suitable break in the operation for the equipment that must be maintained. 

The market demand must be satisfied. This means that the demanded quantities of the final products S3 and S4 must be present in the storage tanks when they have to be delivered to the customer. Such due dates or deadlines define timing constraints for the end of the production. Missing a due date often causes a penalty (or the customer pays less to the plant operator). Missing a deadline is not allowed here the customer must be satisfied before the deadline expires. 

Maintenance history is an essential component of GxP compliance. Work instructions and SOPs controlling maintenance operations should ensure that the maintenance engineer records aU performance measures, observations, and maintenance tasks in a consistent manner with calibration records, for example, containing calibration parameters, with calibration procedure, reference to calibration equipment, name of engineer, date of calibration, next due date, etc. Where automated condition and performance monitoring is employed, the integrity of the recorded data is obviously a GxP issue. 

It is desired to produce a list of N batches of different products so as to minimize a composite performance index that consists of a weighted sum of three terms namely due date penalties, change over costs and completion times of last batches or jobs on the two production lines. The scheduling algorithm is to determine the processing orders of various jobs on each batch unit and the start times of all operations. 

Periodically, a preventive maintenance inspection is made. If the inspection reveals serious wear, some maintenance operation is performed to restore the component or subassembly to a good state of repair, and reduce the probability of failure. A PM system increases the probability that the equipment will perform as expected without failure until the next inspection due date. 

Detailed scheduling of the various elements of a production system is crucial to the efficiency and control of operations. Orders have to be released and have to be translated into one or more jobs with associated due dates. The jobs often have to be processed by the machines of a workcenter in a given order or sequence. Queueing may occur when jobs have to wait for processing on machines... 

Assume now that each operation j to be scheduled on machine i, i M — M , has to be processed in a time window of which the release dates and due dates are determined by the critical (longest) paths in G. Consider each one of the machines in M — as a separate problem where... 

Under APS, planning, with its synchronization emphasis, dominates and sequencing (or scheduling) is subservient to it. The operations to manufacture a part are initiedly placed in the plan to support a global criterion, say customer order due date, tmd then the sequencing of these operations is done to adhere to the plan as closely as possible. 

Adam, N., Bertrand, W., Morehead, D. and Suikis, J., 1993. Due-date assignment procedures with dynamically updated coefficients for multilevel assembly job shops. European Journal of Operational Research, 68(2), 212-227. 

Bagchi, U., Sullivan, R.S. and Chang, Y.L., 1987. Minimizing mean square deviation of completion times about a common due date. Management Sciences, 33, 894-906. Baker, K.R. and Scudder, G.D., 1990. Sequencing with earliness and tardiness penalties a review. Operations Research, 38(1), 22-36. 

De, P, Ghosh, J.B. and Wells, C.E., 1991. Scheduling to minimize weighted earliness and tardiness about a common due-date. Computers Operations Research, 18(5), 465 75. De, R, Ghosh, J.B. and Wells, C.E., 1993. On the general solution for a class of early/tardy problems. Computers Operations Research, 20(2), 141-149. 

Hall, N.G., Kubiak, W. and Sethi, S.P., 1991. Earliness-tardiness scheduling problems, II deviation of completion times about a restrictive common due date. Operations... 

Hoogeveen, J.A. and van de Velde, S.L., 1991. Scheduling around a small common due date. European Journal of Operational Research, 55,237-242. 

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