Formation and dynamic routing of part families among flexible manufacturing cells

Because of the nature of 0-1 part-family incidence matrix, a multi-cell flexible manufacturing systems (MCFMS) using conventional part-family formation algorithms, such as array-based clustering, similarity coefficient-based clustering, and mathematical programming, in a cellular manufacturing mode can assign a part only to one machine cell. The consequence is that each part type has a fixed route through the system. When each part is limited to a fixed route through the system, the performance of a MCFMS is diminished. This is because the inherent flexibility of the FMS is not fully utilized. This research proposes a dynamic routing method that applies a fuzzy clustering algorithm and certainty factors. The fuzzy clustering algorithm, in which a part can belong to all families with different degrees of membership, provides extra information that is not available in conventional algorithms. This information would permit managers to make better informed dynamic routing decisions and allow for more flexible assignment of parts to flexible manufacturing cells (FMCs). This is important information and would be especially useful in balancing machine cell workloads. A workload imbalance among FMCs can cause excessive flowtimes and tardiness, and low rates of machine utilization.