Improving a practical drum–buffer–rope buffering approach using Workload Control

This paper deals with improving the lead-time performance of a small packaging manufacturer in the Netherlands that had already implemented several facets of Theory of Constraints (TOC) in 1997. Since then, delivery reliability and profits have increased and lead-times reduced substantially. In an attempt to achieve further lead-time improvements in 2001, the firm recently encountered some limitations of its partial TOC implementation. In this paper we focus on the modifications of its order acceptance and buffer management system that were necessary in order to obtain the desired lead-time reduction. We describe how Workload Control principles were introduced to improve the buffering approach and planning procedures the firm had been using since 1997. It shows that Workload Control provides effective tools that can be used in combination with the Drum–Buffer–Rope mechanism in order to balance the flow of work to the production floor.