If someone were to force me into a corner and only allow me to use one metric in my plant I would have to choose Overall Equipment Effectiveness (OEE). The reason I would pick it is simple… it is really 3 metrics in one! Here is a quick summary of how this powerful metric works.
The 3 Pieces of OEE
OEE looks at 3 areas:
- Performance: Here we compare the actual output with what that particular piece of equipment should be producing. We are really focusing in on what we call “speed losses.” For example, due to the hardness of a particular material the lathe may need to run at a slower speed than normal. So, in a given day a machine should produce 100 widgets but at the end of the day it only produces 85 widgets so we have a performance of 85% (85/100).
- Availability: Here we look at how much time is available to run the machine (taking out breaks, etc.) and how much we actually ran the machine. With availability we are primarily looking at our losses associated with downtime. Things like setup time, machine breakdowns, and startup losses are common culprits of availability losses. So, if there were 7 hours available to run the machine and we actually ran 6 hours our performance is 86% (6/7).
- Quality: Lastly OEE also looks at quality. If 80 out of the 85 widgets were acceptable (5 bad) we have a quality score of 94% (80/85).
Once we have our three percentages we simply multiply them together to get our OEE. In our example, we have an OEE of 69% (85% x 86% x 94%).
Depending on which book you read or consultant you talk to you will hear various opinions of what “world class” OEE is. I work with the thought that if you have an OEE of 80% or more you are doing well. Really well actually!
Not Just for TPM Programs!
The one thing that really irritates me is how so many people think OEE is just a maintenance thing. If we go back to the aforementioned books and consultants we mostly hear about OEE in the TPM (Total Productive Maintenance) chapter or module. This is fine as OEE and TPM definitely go together. But let me just get on my soapbox for a bit. OEE is arguable to most holistic productivity metric known to mankind.
So if you think the maintenance guys are the only people that should be driving OEE with their TPM program you are dead wrong. Anyone and everyone that cares how many widgets are produced in the plant should care about OEE.
The operator should care (and be intimately involved in capturing the data). The line supervisor should care. The quality manager should care. The plant manager should definitely care. The maintenance team should care. Even the controller, who wants to see all the cash flowing on the financial statements, should care. Heck, your significant other, who wants to see you employed for a long time, should care about OEE! It’s just that important.
Here is free video and OEE calculator you can download. And yes, I know, it is in the TPM section of this website. C’est la vie.
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