Sequencing and scheduling of job and tool in a flexible manufacturing cell

Flexible manufacturing cells (FMCs) are now common place in many manufacturing companies, due to their numerous advantages such as the production of a wide range of part types with short lead times, low work-in-progress, economical production of small batches and high resource utilization. Part and tool flows, two major dynamic entities, are the key factors and their management plays an important role in the operation of a FMC. The theme of this paper is to a generate joint operation - tool schedule in a FMC consisting of several machines and a common tool magazine (CTM). To achieve this aim, the jobs and tools must be jointly sequenced and scheduled in a tool constrained environment. Two heuristic algorithms, priority dispatching rules algorithm (PDRA) and simulated annealing algorithm (SAA) are proposed to derive optimal solutions. PDRA, are the most frequently applied heuristics for solving job shop/combinatorial scheduling problems in practice because of their ease of implementation and their low complexity, when compared with excel algorithms. SAA that belong to search categories, which are emerging along with the high computational capability of computers, can be used for FMS scheduling problems. Both adopt the Giffler & Thompson procedure for active feasible schedule generation. The performance of these two algorithms is compared with makespan and computational time. The analysis reveals that the SAA based heuristic provides an optimal or near optimal solution with reasonable computational time.