The impact of a constraint buffer in a flow shop

This article presents the findings from a simulation using actual production data comparing the material requirements planning (MRP) scheduling method with that of drum-buffer-rope (DBR) from the theory of constraints (TOC), previously called OPT. The simulation is based on production information from a diesel engine factory currently using MRP. The same data were then used under DBR procedures. Care was taken to utilize the DBR method in the manner suggested in the TOC literature. A buffer-modified MRP was also modeled. This environment used MRP scheduling with a buffer inserted prior to the constraining operation. An analysis of variance of the results of all scenarios indicates that the constraint buffer used in DBR was successful in increasing output from the system.