Integrated Production Scheduling for Hot Rolling and Delivery with Time Windows

Hot rolling is the last process of steel-making production, where the slabs are rolled into designated specifications according to the requirements of variant customer orders. The scheduling problem of hot rolling is complicated due to the diversified and strict production constraints. As the follow-up stage of the hot rolling, transportation of final products determines the delivery time of each order. Although the two stages are closely related, each one may be optimized separately in the traditional scheduling methods, the unified optimization cannot be achieved. In this paper, a mathematical model is proposed to formulate the problem of integrated production for both hot rolling and delivery stages. And a dynamic programming algorithm with tabu search is proposed to solve the problem in the single rolling mill production environment. At last, the effectiveness of the algorithm is verified by comparing with MV heuristic algorithm in different scales of computational experiments.