AN INVESTIGATION OF SCHEDULING POLICIES IN A DUAL-CONSTRAINED MANUFACTURING CELL

In previous group scheduling studies, labor has essentially been ignor ed by assuming that enough labor is assigned to each machine in the ce ll. In reality, however, management usually does not have the resource s to employ a laborer at each machine in the cell (i.e., machines need to share labor). Both labor scheduling and group scheduling heuristic s need to be administered to manage the cell effectively. This study d evelops and examines scheduling procedures for a dual-constrained (i.e ., machine and labor) manufacturing cell. Eleven decision rules are de veloped and tested under 16 different experimental conditions. The exp erimental factors used are interarrival time distribution, cell load, setup-to-run-time ratio, and transfer-to-run-time ratio. Results show that interarrival time distribution and cell load have the greatest im pact on the performance of the cell. This suggests that effective prod uction planning aimed at reducing job arrival variation and leveling t he cell load can substantially improve cell performance. Among the exp erimental factors, setup and transfer-to-run-time ratio factors had th e strongest influence on the rankings of the decision rules. These ran kings were fairly robust across all experimental conditions and perfor mance measures. The results also indicated that the inclusion of labor as a contraint in the cell had a significant impact on the performanc e of several group scheduling heuristics. Finally, it was shown that t he best performing decision rules consider both transfer time and subf amily setup times.