Textile production systems: A succession of non-identical parallel processor shops

The different problems of sequencing production operations in parallel processor shops of a textile company are considered in this paper. The complexity of these problems depend on: (1) the machine changeover times which occur when the changeovers cannot be realized in parallel during processing times, and (2) the operation due dates which have to be at best respected when the workshops do not constitute stocks. The objective is to minimize mean completion time or mean tardiness. This paper models these different scheduling problems. It presents some tools to solve these problems, and it explains the choice of algorithms issued from the graph theory and employed in industrial studies. Some results are shown.