A Hierarchical Approach for Lot-sizing and Production Scheduling of Complementary Product Packages

The lot sizing and scheduling problems for quick response to the diverse customers’ demands through the optimal utilization of resources and reducing the costs has a particular importance. In this paper, it is investigated the lot sizing and scheduling problem for complementary products. Each package consists of several complementary products with certain portions and different processing times, producing on the parallel production lines in a make-to-stock environment. To solve the problem, it is proposed a hierarchical approach with the objectives of minimizing the package costs, bound and stock, and maximizing the capacity utilization at the first level, and the aim of minimizing the completion time of complementary products at the second level. The second level model is difficult-to-solve in the large-sized instances; therefore, a rolling horizon heuristic solution algorithm is developed whose comparing performance to the exact solution as well as a proposed lower bound in different numerical examples, show the solution quality and its appropriate computation time. To validate the model, the actual data of a tile factory have been employed. Results show that the production plan, costs and times to complete the packages are improved, compared to the current process in the factory.