Revising the master production schedule in sequence dependent processes

Revising the master production schedule (MPS) in a rolling planning horizon environment to improve plant performance is critical in process industries with sequence dependent changeovers. Plant performance is defined in terms of process changeover time, total shortages, and finished goods inventory. Two heuristics for revising the MPS are introduced and tested against a rolling horizon MPS that does not take sequence dependent changeovers into consideration. These two heuristics represent two different approaches to heuristic design: local interchange (SWAP) and global interchange (3OPT). Simulation experiments are reported that test the performance of the two different approaches to revising the MPS in process industries with sequence dependent changeovers. The MPS designs were tested under plant conditions that are frequently encountered in process industries. The results indicate that revising the MPS in process industries significantly improves plant performance. In addition, 3OPT provides a major improvement in changeover time, while SWAP provides improvement in total shortages.