Hot-Rolling Batch Planning Problem of Round Bar with Roller Capacity

Considering the feature of roller capacity with dynamics change in round bar production, a hot-rolling batch planning problem is studied. Firstly, the problem is formulated as a different capacities vehicle routing problem (DCVRP). And then, a mathematic model is built with two optimization objectives, minimization for total set-up time and maximization for utilization of roller. Secondly, an algorithm based on constraint satisfaction technique is present with variable selection rules and value selection rules for billet selecting, grouping and sequencing, and constraint propagation for searching-space reducing and rolling-unit partitioning. Meanwhile, the current capacity of online roller is updated dynamically during the solving process of algorithm. Finally, comparing results indicated that the proposed model and algorithm are effective and efficient.