Improving job shop performance through process queue management under transfer batching

This research investigated the value of protecting the continuity of release batches in a transfer batching environment, by modifying the shortest processing time (SPT) rule. A simulation model of a job shop was used to test the modified SPT rule. The performance measures evaluated were mean flow time, flow time variance, and mean lateness. Conditions under which the SPT modification improves results were as follows: large number of transfer batches, small setup time to process time ratio, and large variation in process times from station to station. The results suggest that shop loading is not a significant factor affecting peformance of the modified SPT rule.