BATCH-PRODUCTION AND PREVENTIVE MAINTENANCE SCHEDULING UNDER EQUIPMENT FAILURE UNCERTAINTY

This paper deals with production scheduling of multipurpose batch plan ts in the presence of equipment failure uncertainty. Uncertainty analy sis is incorporated at the production scheduling stage to improve the probability of performing the resulting schedule. So, the need of comp lete rescheduling of the production plan is reduced and more effective reactive scheduling strategies can be applied each time a deviation f rom the expected plant status occurs. The probability of performing th e predicted schedule will depend on equipment failure forecasts. The e ffects of equipment failure on the production schedule are minimized b y computing the reliability indexes for each plant unit and for each s cheduled task. Avoiding the use of equipment with low reliability inde xes is balanced against production requirements (demand). Preventive m aintenance tasks may be also introduced to compensate for possible del ays produced by the use of equipment units with low reliability indexe s. The incorporation of these methodologies into the overall planning framework is also shown and illustrated with case studies. (C) 1997 El sevier Science Ltd.