Q: My OEE goes over 100%. What did I do wrong?
We came up with the following reasons why this could happen
1. our time normes are not ok and our people can reach very quickly speeds over 100%
2. We have 0 ppm and 0 bad parts, but I don’t think that this can be reach even in a fully automated process.
3. We didn’t stop for maintenance of the machine – but on the long term I don’t think that this is achievable.
Arno Koch • Indeed, if OEE goes over 100% the definitions should be carefully checked since with correct definitions (and without seriously reengineered machine or product) this is not possible.
So let’s look at your possible causes: Not stopping for maintenance can not be the cause for this phenomenon since in that case availability would go up, maybe even until 100%, but it never can go over 100% since you can not put more time in a shift than 100%.
Not reporting defects does not influence the performance rate since this by definition contains good and rejected product. It would raise the quality rate, but you can not make more than 100% quality.
Cheating on run time (you say you where running during the break but didn’t) does raise availability but equally decreases performance.
“Hiding” time (you where running but did not report it) could bring up the phenomenon, but why would anyone do this regularly?
The way to achieve this phenomenon is to produce more output than possible according to the definition; so in cases where the defined maximum speed is not the real maximum. This is the reason why the THEORETICAL maximum should be defined and not some practical maximum that is just practical for the moment but can be improved in time.
The rule is:
The real maximum speed can only be improved by reengineering the machine or product.
Also see: “Can performance go over 100%?”