Production Scheduling of Flexible Manufacturing Systems

This paper deals with the production scheduling of a flexible manufacturing system which consists of machine tools, buffer storages, and material and cutting tool transportation systems. The parts are produced randomly, and alternative machine tools for each processing stage of parts are permitted. Each machine tool has a buffer of specified capacity and some particular cutting tools for common use are automatically delivered by a cutting tool transportation system. The problem is to determine the schedules of machining and transporting parts, and of transporting cutting tools simultaneously so as to minimize the makespan of production. A heuristic procedure is presented to obtain better schedules by using the decision rules. A new decision rule, named ESTA (Earliest Starting Time with Alternatives considered), is proposed to achieve a high utilization of the machine tools and the transportation systems. An experimental comparison is performed to investigate the effectiveness of the proposed decision rules through a case study.