Energy-efficient hybrid flow-shop scheduling considering job batching

Production scheduling is an effective measure to improve efficiency and reduce energy consumption (EC) in a hybrid flow shop. Taking the constraints of workpiece transport and tool change into account, a new energy-efficient hybrid flow-shop scheduling (EHFS) model with EC and makespan as the optimization objectives was established by combining tool blunt standard-based job equal batching method and “turn off/on” energy-saving strategy. Then, the non-dominated sorting genetic algorithm-II (NSGA-II) was employed to solve it. In a hybrid flow shop environment, the proposed EHFS model can make a trade-off between two optimization objectives, then rationally arrange processing batches for various types of jobs, select suitable machines to process each batch, and reasonably arrange the execution sequence of the relevant batch operations and the application of “turn off/on” energy-saving strategy on each machine simultaneously. Finally, the energy-saving effect of the proposed EHFS model and the effectiveness of its solution method were verified by the case study.