Q: We run a 3 shift operation of 120 hrs a week.
Some of our machines are not 100% loaded due to the product mix we have.
How should we calculate the OEE?
During some product-mixes we do not use a certain machine because, for example, line A can run products in sizes 10mm to 50mm and line B can run products from 45mm to 100mm.
What would be the OEE in the following example?
- Machine A is planned to run only 80hrs of it’s possible 120hrs per week
- It has 20 hrs breakdown
- Assume the Performance and Quality 100%
Reading the site I expect it to be 20/80 but I’m getting disagreements at work.
Arno Koch • OEE is an instrument to measure equipment effectiveness from the perspective of the shopfloor team. So the shopfloor team measures OEE from the machine it is working on.
The machine is basically scheduled to run 3 shifts, so one would expect to have an OEE measured in these 3 shifts.
But: due to market-constraints (for product that can be produced on a certain machine) a machine is taken out of the shift schedule; it is being un-scheduled.
In your example it is un-scheduled for 40 hrs; there is no team at the machine, the machine is not running. So there is no OEE.
The OEE’s availability would now be:
Running time (60) / (Scheduled time (120) – Unscheduled time (40) ) = 75%
BUT…. The machine COULD have been running IF there were a different product mix or no market constraint! So this is a matter for the operations management to see and act upon.
That’s why –beside OEE– we also look at the OOE, the Overall Operations Effectiveness.
In the OOE we do not care about unscheduled, planned or not, we consider the total available shift time of the regular shift-schedule as 100%.
So your OOE’s availability would be:
Running time (60) / (Planned time (80) + Unscheduled time (40) ) = 50%
Or in other words:
Running time (60) / Total Shift schedule (120) = 50%
The owners of the facility could even extent this way of thinking and ask you: “Why is the machine only scheduled for 120 hrs? There are 168 hrs in a week; the machine could be operated in a 5 shift operation!”
That’s why there is TEEP, which takes 24/7 as 100%
So now your example would bring how much TEEP availability?
Running time (60) / (Planned time (80) + Unscheduled time (40) + not scheduled (48)) = 35,7%
Or in other words:
Running time (60) / total time (168) = 35,7%
Where is the difference?
OEE, OOE and TEEP are being calculated based on the same numbers. They only take a different reference value for “maximum time” and thus they will show a different loss-cascade.
The shopfloor-team will focus on the part they can and should influence; the time they are operating a machine that has demand. Operations management and higher management should support this ánd do their part also.