Design of Mixed-product line production system by multi-objective genetic algorithm

There are two essential operations management problems in Mixed-product line, line balancing and product sequencing, which are tightly interrelated. To design of mixed-product line production system, hierarchical design procedure for line balancing and model sequencing is proposed. It is structured in terms of amelioration procedure. On the basis of our evolutionary algorithm, a genetic encoding procedure entitled Priority-based Multi-Chromosome (PMC) is proposed. It features a multi-functional chromosome and provides efficient representation of task assignment to workstations and model sequencing. The lean production perspective recognizes the U-shape assembly line system as more advanced and beneficial compared to the traditional straight line system. To assure the effectiveness of the proposed procedure, both straight and U-shape assembly lines are examined under two major performance criteria, i.e. number of workstations (or line efficiency) as static criterion and variance of workload (line and models) as dynamic criterion. The results of simulation experiments suggest that the proposed procedure is an effective management tool of mixed-model assembly line system.