Q: I am having a problem changing the Name Plate capacity (NPC) on one of my lines. The line in the past was 3.153pcs/min and now needs to be changed to 2.685pcs/min. When I change the Name Plate Capacity of the Machine settings to the new value and enter the Production for the line I still get the 3.153pcs/min. Should I not use the new, lower settings now?
Arno Koch • It is not the Name Plate Capacity (NPC) that determines the OEE but the ‘Standard’, which is the theoretical maximum speed of a certain product(group) on that equipment.
Name Plate capacity versus the Standard
The NPC is used to calculate the OEE Top value; meaning the OEE regardless differences in product.
The Standard is the Theoretical Maximum Speed of a specific product on a certain machine. (Read more here)
So what you are probably looking for is to change ‘the Standard’, the maximum speed of a product on a machine.
When change the Name Plate Capacity or Maximum Speed?
The machine or product have been changed
If the machine or the product was modified, leading to a higher speed, the value should be changed. From that moment on, the next calculations will use the new speed, older calculations will use the old speed.
The speed was set wrong form the beginning
in cases where the maximum speed was wrongly defined from the beginning, all calculations need to be recalculated retrospective, to correct this error.
Why to lower the maximum speed?
My question here would be; Why would you lower your maximum speed? To raise the OEE? Having a too high maximum speed can’t harm. Your OEE will be a bit lower; so what. Important is that your operators keep looking for losses and thus potential improvement.
Setting the maximum speed definition lower than theoretical possible speed means there will be a day you go over it; thus having a performance rate over 100%. Of course that is ‘impossible’, meaning at that point you will have to change the speed again…
The shame of a high OEE
My advise; in case of doubt ALWAYS set speed higher than whatever you think is possible, NEVER build in hidden losses by lowering the maximum speed. It is not a shame to have an OEE that is not 85% because it will lead you to improvement.
It is a shame having a high OEE while the machine is running far below real maximum capacity and nobody is looking for improvement because the number says it is ok….!
There are no excuses for not being perfect.
There are only causes to be removed!