Analysis of sequencing heuristics in a flexible flow system with hybrid order shipment environments

This study investigates the performance of order-input sequencing heuristics in a realistic flexible flow system (FFS) with hybrid order shipment environments. An FFS is a dedicated flexible manufacturing system where the routing of parts is unidirectional. This study examines two types of sequencing heuristics: two-stage (group scheduling) heuristics and single-stage heuristics. Results of the analysis of variance show that the ratio of permitted to forbidden early shipments exhibits statistical significance for measures of the average time in system and average lateness. Results of the paired t-test analysis show that two-stage heuristics outperform single-stage heuristics under each experimental condition for each measure. The superior performance of the two-stage heuristics is due to the reduction in major (or subfamily) setup times. Finally, results of the paired t-test analysis can provide guidance for schedulers in the selection of preferable heuristics for relevant FFSs.