Dynamic Hybrid Flowshop Scheduling with Batching Production

Based on the background of steel-tube production, this paper presents the dynamic hybrid flowshop scheduling with batching scheduling at the first stage, and establishes an integer programming model for this problem. The objective is to minimize the total weighted completion time. The Lagrangian relaxation algorithm is constructed to slove the above model where dynamic programming is presented to solve batch-level subproblems, and a two-stage heuristic is presented to construct a feasible schedule. Testing results on small to medium problem sizes show that this method can obtain satisfactory quality solution in a shorter computation time.