Batching to minimize total production time for two part types

Consider the jobs at a bottleneck facility for two subsequent production lines, each of which is dedicated to produce a part type. When the bottleneck is changed over from jobs in one part type to jobs in the other, a change-over time is required as the components supplied by the bottleneck for the two subsequent lines are different. There is a trade-off between keeping the change-overs small, by having large batches, and keeping both the inventory small and the lines busy, by having small batches. A heuristic is proposed in this paper to batch jobs for the two part types so as to reduce the total production time. The heuristic is conceptually easy and can be used to solve large-sized problems in a short time. Computational results show that the heuristic produces solutions with an average of 99.90% improvement over sequences without batching.