Goldratt SIM – Maintenance Depot

Goldratt Maintenance Depot Simulation is a dynamic simulation model that was designed to answer three simple but important questions: 1) Are we able to predict the impact of variability on a system? 2) How much better can we do if we are willing to change from PUSH to PULL based planning and execution rules. In this model, the PULL environment is based on Theory of Constraints' Critical Chain Project Management (CCPM) and Demand-Driven Replenishment with Dynamic Buffer Resizing. In Round 1 the Maintenance Depot is run with no variability in order to create a baseline to compare the impact of changes. In Round 2 variability in both the arrival of airplanes and the supply of parts is introduced and all key performance metrics deteriorate dramatically. In Round 3 simple management rules are changed to improve operational and financial performance of the maintenance depot. These are: Work is never started without a full kit. Prioritization of work is based on the percentage buffer penetration. Work in progress (WIP) is limited and no multitasking is allowed. In Round 4 we stop making use of a Min-Max ordering policy and synchronize the Maintenance Depot with the part suppliers. We also dynamically adjust the buffers of the parts based on actual demand. This model simulates the entire supply chain and highlights the negative impact that demand and supply variability has on operational and financial performance as well as the positive impact on all key performance metrics when switching from PUSH to PULL. The objective is to see if by simply changing the rules how close can we get to the perfect world results when there was no variability. We would love to hear from you, for comments or suggestions write to us at apps@goldrattresearchlabs.com