This article explains what characterizes a good OEE score. OEE stands for “overall equipment effectiveness” and is the leading standard for measuring manufacturing productivity. OEE gives you a handle for monitoring your systems’ performance, identifying deficits, and developing measures for improving the situation.
An OEE metric is calculated from three factors: machine availability, performance, and the quality of produced products. Accordingly, the formula is: OEE = availability x performance x quality.
Characteristic OEE score ranges and what they mean
If nothing whatsoever is negatively impacting any of the three OEE parameters – availability, performance and quality – then you have a perfect OEE score of 100%, which means that you’re producing exclusively good parts as quickly as possible without any downtime. In the real world, this theoretical score isn’t feasible. But any OEE score greater than 85% is considered world-class. Most manufacturing operations have an OEE score between 65% and 85%. It’s safe to assume that the processes of any plant with an OEE score less than 65% suffer from considerable deficits. An OEE score this low is a warning signal.
The following overview provides a basis for interpreting OEE scores:
OEE score < 65 %
An OEE score of less than 65% indicates that there is considerable room for improvement because available capacities aren’t being optimally utilized. In this situation, there’s an urgent need to thoroughly analyze the factors that are contributing to stops and lost production. It’s advisable to analyze frequently occurring problems to detect and get them under control before they can get out of hand.
OEE score between 65 % and 85 %
Most manufacturing operations are in this range. But although these values are typical, they also show that there is room for improvement. In such a case, it can be advisable to implement processes for automatic optimization and continual monitoring of the systems.
OEE score > 85 %
Manufacturing operations with an OEE score above 85% are in the top echelon. They set the benchmark for other, less successful operations to follow. With conventional assets, however, it isn’t realistic to strive for a score much higher than 85%. Some machines used in the automotive industry attain an OEE value of 90%, which is exceptional. Ideally, an efficient machine should always run at top speed without turning out any defective parts. But 100% effectiveness is impossible to sustain, since even the best machines eventually require maintenance or retooling.
What to keep in mind for interpreting OEE scores in general and peak values in particular
It’s important to differentiate when interpreting OEE scores. For example, you need to take the machine type and/or production mechanism into account. An OEE score of 90% can actually be at the low end for machines that operate completely continuously, while an OEE score of 60% may already be the upper limit for complex manufacturing processes.
The realistically achievable maximum with “conventional” machines is somewhere above 85%. This means that, for example, 99% of products are manufactured to specs and the system runs at 95% of its theoretical top speed 90% of the time. This gives us the following equation: 99% quality x 95% speed x 90% running time equals 85% effectiveness. This is a generalized example that describes the approximate upper limit achievable with conventional manufacturing processes. Every case is different, however, and can vary depending on the industry and machine type.
In practice it can be laborious to calculate an OEE score without know-how and experience. OEE is the basis for objectively determining and measuring losses, which can then be reduced or eliminated by appropriately analyzing the causes and taking corrective action to achieve an excellent OEE with corresponding cost savings.
Do you want to quickly and cost-effectively determine the OEE scores of your company’s systems? If so, please talk to one of our experts. We’ll be glad to help you achieve your goals.