Modified CONWIP systems: a review and classification

Purpose: Constant work-in-process (CONWIP) system is one of the most recognised pull systems. New CONWIP systems are constantly derived in research. This study reviews and classifies these new (modified) systems. Methodology: Relevant studies are systematically screened and reviewed. The general breakdown of workload control provides several forms of differentiation to build the scheme. Shared attributes that separate one system from others were used as elements in the classification scheme. The rationale and implication of using these elements are discussed. Findings: In total, 15 modified CONWIP systems are reviewed. Research limitations: Several production planning and control functions are not considered, and these include order entry, protective WIP, product mix, and process characteristics are not considered. Originality: This study contributes to the understanding of CONWIP systems and is the first classification scheme based on the fundamental characteristics of the original system. The exploitations of these characteristics are documented and explained.