This paper presents a job scheduling model of M identical machines in parallel. The model assumes that a significant set-up time is incurred when a machine changes from processing one type of parts to a different type of parts. A problem is examined that determines the quantity and the schedule of each part type to be processed on each machine. The objective of this problem is to minimize the total completion time. A heuristic approach and two lower bounds on the optimal completion time are presented. In addition, the efficiency of this heuristic is tested on several groups of random problems.
