Overall equipment effectiveness is a manufacturing metric that's a measure of manufacturing productivity. It represents the percentage of manufacturing time that is truly productive. OEE is a blended ratio of availability (uptime rate), performance, and quality (yield). ^[My hunch is that OEE is a time-based ratio because time-based utilization is a good proxy for amortized capex utilization] $ OEE = Availability \times Performance \times Quality $ As a blended ratio, it's important to not blindly gaming the single OEE metric but understand the impact of its factors. e.g. you wouldn't want to trade 5% Availability for 4.5% Quality just to say that your overall OEE metric is higher. ## Factors The general idea is to start by considering 24/7 (all time) and attribute shortcomings to losses. The goal isn't just to measure OEE for the sake of having a metric but rather to maximize Fully productive Time by understanding how the factors are affected. ![[_Media/oee-breakdown-image.png]] *Since OEE is focused on equipment effectiveness, we don't include **Schedule Loss** in OEE.* Each of the factors of OEE takes into account a different type of loss. - **Availability** 100% means the process is always running during planned production time ^[does not include scheduled downtime but does include planned stops that are part of the process like changeover time.] ^[this means availability and hence OEE isn't a complete picture of all losses nor of capex utilization e.g. 20% scheduled downtime isn't the same as 10% from a utilization perspective. Schedule losses are accounted for in [[Total Effective Equipment Performance|TEEP]].] $ RunTime = PlannedProductionTime - AvailabilityLoss $ - **Performance** 100% means that when the process is running, it's running at it's target throughput ^[what does it mean when you tune a process to go above the original design throughput] - e.g. machine wear, bad materials, miss-feeds, jams, setup and adjustment... $ NetRunTime = RunTime - PerformanceLoss $ - **Quality** 100% means only good parts are being produced ^[There are obvious interactions here e.g. first pass yield quality vs final yield accounting for rework which impacts cycle time and hence performance. The relationship is process-dependent. A 1% bump in quality != 1% drop in performance] $ FullyProductiveTime = NetRunTime - QualityLoss $ The 3 OEE factors are often broken down into the so called [[OEE Six big losses]]. ## Calculation $ $ *Which means OEE will always be lower than any of its components.* ## Resources - [Overall equipment effectiveness - wikipedia](https://en.wikipedia.org/wiki/Overall_equipment_effectiveness) - [Understanding OEE in Lean Manufacturing | Lean Production](https://www.leanproduction.com/oee/) - [What Is OEE (Overall Equipment Effectiveness)? | OEE](https://www.oee.com/) --- - Links: [[Single-Minute Exchange of Die]] [[TEEP]] [[Common manufacturing metrics]] - Created at: [[2021-10-12]]