EVALUATING ORDER RELEASE MECHANISMS IN A JOB SHOP WITH SEQUENCE-DEPENDENT SETUP TIMES

Job-release mechanisms in job-shop control are receiving increased recognition in recent research. However, there is considerable disagreement over the benefits of sophisticated job-release mechanisms, and they remain to be tested in various operating environments. In our study, we extend previous job-releasing research by examining several job-release mechanisms in a different operating environment-a sequence-dependent setup job shop. We tested these release mechanisms, originally developed for a machine-constrained job shop, in conjunction with two groups of sequencing rules-ordinary and setup-oriented sequencing rules. We measured shop performance in terms of total cost, the sum of inventory-holding and late-penalty costs. We developed a simulation model of a nine-machine job shop for our experiment.