Performance of hybrid cellular manufacturing systems: a computer simulation investigation

In this paper, the performance of hybrid cellular manufacturing (CM) systems is compared with that of functional layouts that use traditional job shop procedures as well as part family scheduling rules, under a variety of shop operating conditions. Unlike much of past research in group technology (GT), this work examines the entire shop floor, in which the CM systems comprise cells and a remainder shop organized as a functional layout. The experimental factors investigated include: the system (two functional layouts and five hybrid systems); setup factor, a surrogate for the degree of part family similarities; scheduling rule, which includes both job shop and part family-oriented rules; and lot size. The performance measures used were flow time, work-in-process inventory, machine utilization and flow ratio. Several findings emerged that form a useful addition to the literature. While part family-oriented scheduling rules significantly outperformed job shop rules, little difference was detected among the former. The results also indicated that the performance of the remainder shop deteriorated with increasing conversion, due to erosion of pooling synergy.