Rapid Modeling In A Lean Context

Abstract

Lean management is widespread but theoretical models that scientifically substantiate the lean practice are scarce. We show how queuing models of manufacturing systems and supply chains underpin the practice of Lean. Two quantitative performance models which relate the system parameters with the system performance in terms of lead time and throughput will be discussed, including an exogenous definition of Lean. We show that the ideal level (i.e., the Lean level) of the system buffers (safety capacity, work-in-process and safety time) are determined by the targeted system performance. Moreover, the lean concept is dynamic in nature: when either system characteristics or target performance change, the lean buffer levels change accordingly. The latter stresses the need for a comprehensive, analytical and consistent approach. This quantitative approach will be illustrated with lead time and throughput models.