GTBM: An alternative theoretical model to Drum Buffer Rope system evaluation

The Theory of Constraints (TOC) proposed by Eli Goldratt (RIP) from the mid 80´s of last century, supports the material feeding system called DBR (Drum Buffer Rope). This system, which seeks to protect the throughput of the value chain of a production process, is supported on the assumption that the production rate of the total flow is equal to the output rate of the bottleneck and also this restriction is located, in a fixed or variable way over time, in that resource whose capacity or service rate is less than the demand rate. These assumptions are questioned in this article and GTBM system (Global Throughput Buffer Management) is proposed as a theoretical reformulation of the TOC-DBR evaluation approach. A quasi-experimental simulation was developed on the basis of a variable bottleneck configuration of a production process in order to obtain evidence of the effectiveness of the new throughput calculation and it was possible to conclude that GTBM plausibly explains the variations between the overall throughput and the bottleneck´s throughput and, from these variations, GTBM give a better approach of the real impact of expected ROI ( Return of Investment) of the value chain without sacrifice of efficiency for deliveries.