A hierarchical control architecture for constant work-in-process (CONWIP) production systems

In this paper, the authors describe a hierarchical planning framework for a production control mechanism known as constant work in process (CONWIP). CONWIP is a generalization of the kanban system. The result is an integrated system that offers the benefits of just-in-time (JIT) techniques and is applicable to a broader range of production environments than traditional JIT methodologies. A specific implementation of this system has been developed for a large computer manufacturer, and is in the process of installation. The authors focus here on the interactions between the planning modules at the different levels in the hierarchy and on the architecture linking them. For each module, they give citations of appropriate formulations in the literature or, if the problem has not been addressed elsewhere, a specific implementation is described. Modules that are unique to this system are (1) a procedure that establishes an economic production quota and (2) the real-time tracking and (3) the feedback mechanism.