OEE - The meaning of the single number

[Mikael]

Hi

Besides for benchmark and knowing that OEE consist of Availability, Performance and Quality, can I then conclude something from the number, isolated ? So lik 85% OEE means ... ?

 

[msec0990]

While this is something I don't normally deal with (I actually had to look up the acronym) I was able to find the following website: oeefoundation.org

For those like me: OEE = Overall Equipment Effectiveness

Very basically, the website states that the "average" machine runs about 35-45%. The claim is that it really boils down to how it's defined and who is actually doing the measuring. Personally, I don't feel those are numbers I would brag about.

Anyway, I hope this helps.

Mark

 

[Mikael]

Thx, though I have a dozen of explanation on the concept, but others hopefully finds it interesting. At oeecoach I found for me that it gave the best explanation, so I recommend

 

[somashekar]

Its an equipment not a human.
Its there for you begging to be used.
Are you using it 85% ... What is preventing you for not using the 15% ?
Have a project for that ?
OR
Management is satisfied that OEE is 85% ... ?
Don't worry, it will not resign and go elsewhere

 

[reynald]

I think the formula is like
OEE = Availability X Utilization X Yield.

The logic is that given 24 hours, the machine may only be available let's say 90%.
But then even when it is available, it is utilized only 80%.

And for the times it is utilized, it produces only good parts 80%.

From that you can get the real effectiveness of the machine, i.e. the percentage it actually gives value.

 

[Mikael]

Thx, although I dont think you understand my Question. I know very well how it is calculated, and I know what A., P. and Q. means. Separately I can formulate what they tell, but for OEE I can only tell that it is base on the others and use for comparison.

Perhaps I should ask in another way, why not take the average of the 3 components instead?

 

[Bev D]

Mikael - perhaps you could ask your question differently. what is it about OEE that you don't understand: how it is used?

perhaps this is simply a language problem but you seem to be saying that you understand it from a computational perspective, yet you then ask why averages can't be used?

Of course the average availability and productivity could be used ('average yield' is actually total yield percentage if calculated correctly) but it would not be an accurate calculation of OEE.

Based on some of your previous posts I would also add that OEE is not a very good Lean metric as it approaches 100% only when the equipment is running 100% of the time. This is desired in the 'push' world where management is trying to get the most out of its capital assets, but unless every operation is running 100% and single piece flow is occurring, then you have overproduction and excess inventory which are wastes in the lean 'pull' world.

 

[Mikael]

Well you don't need to set the target for 100%! Also you have both OEE, OOE and TEEP.

Anyway let me try to ask like this:


Availability = is about capacity time utilisation.

Performance about = is about speed utilisation, output.

Quality = is about "quantitative quality", output, that is good vs. bad products.

AVA%*PER%*QUA% = OEE% = is about the "overall" yes but what does it mean? tells you that ... ? OEE of 75% tells you that 75% of .... ....

(AVA+PER+QUA)/3 = is about ? tells you that - average yes, but means that ...

 

[reynald]

The concept is analogous to Rolled Throughput Yield, i.e the output of process1 is the input of process2 while the output of process2 is the input of process3. If you have the yield of all three processes, the overall yield = output of process3/input process1 = Y1*Y2*Y3. You don't average as AVG(Y1,Y2,Y3).

The same goes with OEE, you can only utilize the fraction that is available, and %correctly utilized only makes sense from the fraction that is utilized. That is why you take their products

 

[Bev D]

Anyway let me try to ask like this:


AVA%*PER%*QUA% = OEE% = is about the "overall" yes but what does it mean? tells you that ... ? OEE of 75% tells you that 75% of .... ....

it's a straightforward measure: as explained previously, if your OEE is 75% then you are only achieving 75% of the potential output capacity.

(AVA+PER+QUA)/3 = is about ? tells you that - average yes, but means that ...

this formula is nonsensical. adding the 3 measures values is not the correct way - mathematically - to determine equipment utilization...they are like standard deviations. they must be combined as in the above formula. so dividing an incorrect number by 3 tells you nothing as well. this formula doesn't give you the average. You will need to calculate the average availability and the average performance over some period of time and then multiply the 3 proportions together to get the average OEE...