POLCA: Centralised vs. Decentralised Job Release

POLCA (Paired-cell Overlapping Loops of Cards with Authorization) is a production control system specifically designed for low-volume, high-mix and custom-engineered products. It is a visual control system that manages the flow of jobs though the shop floor by making use of overlapping loops of cards between pairs of successive manufacturing cells. These overlapping loops of cards realize a decentralized decision-making structure for job release. This means that jobs do not await release in a centralized pre-shop pool. Rather jobs are immediately forwarded to a gateway manufacturing cells at their shop arrival, where they wait in release lists for available POLCA cards. However, the Workload Control literature has shown that using a centralized pre-shop pool provides important benefits. Therefore, this paper investigates the impact of centralized job release on POLCA performance. Using simulation, we demonstrate that centralized job release outperforms decentralised release if the right card acquisition rule for job release is used. This has important implications for both research and practice calling for more research on POLCA systems.