Materials Flow Control in Multi-cell Manufacturing Systems: The C-CONWIP System

POLCA is a decentralized production control system that controls WIP in pairs of cells. CONWIP is a centralized approach that controls WIP in the whole system. Attempts have been made to apply CONWIP in a decentralized manner, to segments of manufacturing systems, typically job routings. However, when routings are long and diverse, this leads to proliferation of control loops and WIP. The same occurs with POLCA. To deal with this, a new approach that associates control loops to cells, instead of routings, is proposed. Using simulation, we show that this new approach, which simplifies control, outperforms both, POLCA and CONWIP.