Flexible assembly layouts in smart manufacturing: An impact assessment for the automotive industry

Currently, automotive manufacturers take the concept of flexible manufacturing to an unprecedented level, considering the deployment of flexible assembly layouts (also known as matrix production systems) in which automated guided vehicles transport bodyworks on individual routes between assembly stations. To this end, a methodological framework that allows the assessment of the impact of technology choice decisions between traditional assembly lines and flexible assembly layouts as well as the impact of different flexibility levers and configurations is necessary for optimal decision support. We provide such a framework based on analytical insights and a chance-constrained problem formulation. We further show how this problem formulation can be solved optimally using a tailored branch-and-price algorithm. Our results quantify the impact of different flexibility configurations in flexible assembly layouts. We show that flexibility enables a simultaneous improvement in worker utilization and work in progress, resolving a classic trade-off in manufacturing systems. Moreover, we find that worker utilization and output are up to 30% higher in flexible assembly layouts compared with line assembly layouts. Further, flexible assembly layouts prove to be especially beneficial during the ramp-up of vehicles with alternative drivetrain technologies, such as the current transition to electric vehicles.