DESIGN AND SCHEDULING OF HYBRID MULTICELL FLEXIBLE MANUFACTURING SYSTEMS

The objective of this paper is to minimize machine duplication by incr easing its utilization, minimize intercell moves, simplify the schedul ing problem and increase the flexibility of the manufacturing system. An integrated approach of design and scheduling alternative hybrid mul ti-cell flexible manufacturing systems (MCFMSs) in four steps will be presented in this paper. The first step is the implementation of branc h and bound techniques which provide tools to design group technology (GT) cells. The second step is balancing the inter-cell workload of GT cells which leads to a hybrid MCFMS with better utilization of the ma chines. The problem of the exception machines and their utilization an d workload balance will be solved within the MCFMS centre. Thus the pe rformance of GT cells can be improved by transferring workloads from a congested (bottleneck) machine in one cell to an alternative one, a l ess congested (exception) machine in another cell within a group of GT cells forming a MCFMS centre. The third step is the group scheduling; a proposed heuristic method will be used for the scheduling of a fami ly of parts with the objective of minimizing the maximum completion ti me of each part. The problem of scheduling under MCFMS can be reduced by considering the scheduling of each family of parts. Finally, the fl exibility of the system will be enhanced by selecting appropriate mach ine tools and flexible material handling equipments. This approach is both effective and efficient-it has generated a hybrid MCFMS centre wh ich includes several alternatives, for some benchmark problems in much shorter time than algorithms previously reported in the literature. I n addition, the method is conceptually simple and easy to implement.