Abstract:

Currently process planning and shop scheduling are optimized separately. Under the circumstances, the influence of processing methods and process route of each workpiece in process planning on machine allocation, handling distance and processing sequence in scheduling are ignored. In order to further reduce carbon emissions in manufacturing processes, a multi-objective integrated optimization model of process planning and shop scheduling are proposed aiming at minimizing carbon emissions of manufacturing process and makespan to optimize process method of each machining characteristic, process route of each workpiece, processing sequence and machine allocation of each process at the same time. Because there are many parameters to be optimized in the proposed model and they are interactional, a four-segment encoding method is designed to code the related parameters. A NSGA-II algorithm is designed to solve the proposed model. By comparing with results of current separated optimization method of process planning and scheduling, the effect of proposed integrated optimization model on reducing carbon emissions in manufacturing processes is validated.

Key words: process optimization, process planning and scheduling integrated optimization, scheduling optimization, low carbon manufacturing