Title: Managing the effects of variability in drum-buffer-rope systems

Authors: Riham A. Khalil, David J. Stockton, John A. Fresco

Addresses: De Montfort University, Leicester LE1 9BH, UK. ' De Montfort University, Leicester LE1 9BH, UK. ' De Montfort University, Leicester LE1 9BH, UK

Abstract: Drum-Buffer-Rope (DBR) planning and control provides synchronous flow through work areas using minimum amounts of in-process buffer stocks. However, the effectiveness of DBR is compromised by high levels of variability which can cause constraint resources to shift between processes resulting in DBR schedules, buffer positions and buffer sizes becoming ineffective in ensuring maximum system throughput levels. A methodology is presented for measuring the levels of variability at single processes, by combining the variability arising from various sources, such that improved identification of actual and potential constraint resources may be possible. Cycle time probability distributions are developed for individual processes which are then used to identify the relative levels of blocking and waiting that may arise due to differences in variability levels between sequential processes. Using this information, a wider range of methods can then be used to offset the effects of variability and improve the effectiveness of DBR systems.

Keywords: drum-buffer-rope; DBR; synchronous manufacturing; variability; probability distributions; flow lines; constraint resources; throughput levels; blocking levels; waiting times.

DOI: 10.1504/IJISE.2008.015914

International Journal of Industrial and Systems Engineering, 2008 Vol.3 No.1, pp.53 - 69

Published online: 02 Dec 2007 *

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