COBACABANA (Control of Balance by Card Based Navigation): An alternative to kanban in the pure flow shop?

Kanban systems are widely applied in practice as they represent a simple yet effective means of controlling production. But they suffer from a lack of load balancing capabilities, which hinders their application even to pure flow shops if there is variability. In response, this study focuses on COBACABANA (Control of Balance by Card Based Navigation), a card-based production control approach based on the Workload Control concept that was recently introduced in the literature. COBACABANA was developed for high-variety job shop contexts, but we argue it can also provide an important control alternative to kanban systems in pure flow shops. We first show that, in the pure flow shop, the control loop structure of COBACABANA resembles that of a kanban system when the flow of jobs is controlled. But a distinct difference is COBACABANA׳s unique focus on load balancing. Using simulation, we then demonstrate the potential of COBACABANA to improve performance in a pure flow shop with high demand and processing time variability. Results show that a fixed gateway station – inherent to a pure flow shop – presents a structural constraint that makes COBACABANA׳s original starvation avoidance mechanism, which injects work to a starving station, dysfunctional. An alternative is prioritizing jobs with short processing times at upstream stations to ensure quick replenishment takes place at downstream stations threatened by starvation. This has important implications not only for COBACABANA but for priority dispatching. Although card-based systems are typically combined with first-come-first-served dispatching, our results suggest this may be inappropriate in flow shops with processing time variability.