Predictable scheduling of a single machine subject to breakdowns

The predictive production schedule has two important functions; allocating shop resources to the different jobs to optimize some measure of shop performance and serving as a basis for planning activities such as material procurement, preventive maintenance and delivery of orders to external or internal customers. This schedule is modified during execution on the occurrence of disruptions such as machine breakdowns. The schedule modification process may delay or render infeasible the execution of activities planned on the basis of the predictive schedule. Thus it is of interest to develop predictive schedules which can absorb disruptions without affecting planned activities while maintaining high shop performance. A predictable scheduling approach is presented, where the predictive schedule is built with such objectives. The effects of disruptions on planned activities are measured by the difference between planned and realized job completion times. The specific scheduling model considered is minimizing maximum lateness (Lmax) on a single machine with dynamic job arrivals and random machine breakdowns. It is shown that predictable scheduling provides high predictability with minor sacrifices in realized schedule performance.