Aggregate hybrid flowshop scheduling with assembly operations

This paper deals with the hybrid flow shop scheduling (HFS) problem with assembly operation. The parts process on the hybrid flow shop stages and after that in order to produce the final product, several parts go under the assembly operations based on the predefined hierarchy structure of products. Each product has some sub-assembly operations and the final product obtains after completion of the last sub-assembly operation. Our aim in this study is finding the schedule that minimizes the completion time of last final product. For considered problem, we first propose an integer programming model and two heuristic algorithms are then employed. Since this problem is NP-hard, we apply the simulated annealing (SA) approach for large sized problems.