Impact of resequencing on parallel assembly systems

Introduction of flexible parallel assembly in vehicle manufacturing has mitigated some of the quality and throughput problems faced in conventional assembly lines; however, because of lack of coordination with materials downstream the sequence of jobs through parallel machines is not retained. Jobs are resequenced to the input sequence after processing at parallel workstations. This paper considers the effect of resequencing on system performance in terms of throughput and work in process. Results show the relationships between different system parameters that can be used to trade off capital and operating costs. Using a first-come first-serve policy (which is adopted in practice), an algorithm determines the effect on throughput of given system parameters, such as number of parallel stations, number of carriers, and size of the resequencing bay. Strategic implications for design of such systems are discussed based on performance results obtained from simulation.