Integrating flexible-interval preventive maintenance planning with production scheduling

Preventive maintenance (PM) planning and production scheduling are very important problems in the manufacturing industry. In this paper, the authors address production scheduling and PM planning for a single machine. A set of jobs that must be processed in sequence on the machine, which is subject to minimal repair upon failure as well as preventive maintenance (preventive replacement). PM actions are performed under flexible intervals. The authors suppose that the jobs can be resumed without any penalty after either minimal repair or PM actions. The purpose of the scheduling problem is to choose an optimal sequence for the jobs as well as an optimal PM planning which minimise the total weighted expected completion time of the jobs. Genetic algorithm is used to search for the optimal flexible-interval PM planning and job scheduling. The performance of the proposed policy was compared with other policies addressing the same problem of production scheduling and PM planning.