New heuristic for scheduling re-entrant production lines

Today, the scheduling production problem attracts the academic and industrial researchers. This scheduling problem occurs in different types of workshop. However, our study is on an hybrid flow shop scheduling problem type, where the stages are in series and each one is composed of some identical parallel machines. In this hybrid flow shop, orders must be arranged. Each order is composed of several batches with the same due date and can be treated by any machine. Those of some orders must visit twice the stages, and then some flows are re-entrant. Several heuristics are proposed to solve this scheduling problem; the objective is to minimize the total tardiness of the orders. In these algorithms, the list-scheduling method is used. The numerical tests are applied on randomly generated problems. The results show that the proposed algorithm dominates the existing ones.