Heuristics of Scheduling a Single Crane in Batch Annealing Process

The problem studied in this paper concerns enough two-category machine scheduled by a single crane in batch annealing process in the iron and steel manufactory. In the process, machines (furnace and cooler) have to be loaded (unloaded) on (from) jobs sequentially according to technological requirement by crane. This problem can be viewed as two-stage flexible flow shop with additional transportation consideration. Our objective is to minimize the maximum completion time of the last annealed job (makespan). For the strongly NP-hard nature, we mainly propose three heuristics. In order to verify these heuristics, we analyze them from absolute performance point of view and provide the computational experiments.