The impact of protective capacity in implementing drum-buffer-rope methodology in make-to-order environments: an assessment by simulation

Abstract

This study uses simulation to analyse the impact of protective capacity in the implementation of the step 3 of the theory of constraints (TOC) methodology in make-to-order (MTO) environments. The results suggest that at different levels of variability, different levels of protective capacity are needed to keep a system stable and meet the bottleneck (BN) schedule. The higher the variability is, the higher the level of protection needed. The definition of the level of protective capacity required is a strategic decision for the organisation, as it must be emphasised that with high levels of variability in a system, the protective capacity must be very high, which contradicts the efficient use of resources. However, for managers to know and control how much protection is needed without needing additional capacity, it is advisable to monitor the use of protective capacity. This concept of protection monitoring and control is relatively new in the TOC–drum-buffer-rope (TOC-DBR) methodology, but it is applied in the demand-driven adaptive business model, and therefore, should be integrated into the TOC-DBR methodology.