Q: I am having a problem changing the 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 Machinery settings to the new value and enter the Production for the line I still get the 3.153pcs/min. I have even closed the application to update the numbers. How do I change the NPC so it comes up with the new numbers?
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.
The NPC (design speed of the machine) is used to calculate the OEE Top value; meaning the OEE regardless differences in product. (www.oeeIndustryStandard.org)
So what you are probably looking for is to change ‘the Standard’, the maximum speed of a product on a machine.
If the machine was modified, after changing this value, the next calculations will use the new speed, older calculations will use the old speed.
Was it a matter of wrongly defined speed, all calculations would 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 lower than theoretical possible means there will be a day you go over it; thus having a performance rate over 100%. Of course that is ‘impossible’ so than 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….!