Q: The Name Plate Capacity (NPC) is the maximum speed of the machine to run its ideal product. And OEE is calculated based upon different theoretical maximum speeds for different products running on that machine. Now what is OEE Top?
Arno Koch • You describe it right. There is only ONE NPC and there can be multiple Standards (Maximum Speeds) to accommodate the speed differences for different products.
The ideal product for a machine, from perspective of effectiveness, would be a product running at the machines maximum speed.
Not everyone can afford a different machine for each product, and thus we allocate also products to a machine when this is maybe not the ideal combination. So we accept a certain loss in order to be able to run that product.
This is where the OEE Top value comes in. OEE Top calculates the performance rate ALWAYS based upon the NPC. So also for products that run slower and have a lower Standard.
If we can run product B at only halve the speed of product A, the performance of product B would drop to 50%.
Allocate product at more suitable machine
Looking at the cutter example, this indicates you might want to move this product to a heavier cutter that can cut this product in one stroke. This also works in the opposite direction. Imagine there is a product C, half the thickness of product A. What would be the standard?
I would say it has a standard of 120 because the cutter could cut two of these pieces in one stroke.
determining the NPC and the maximum speed
In a technical sense, determining the NPC and the maximum speed for each product on a machine is probably the most difficult part of defining your OEE settings. Always make sure you look for the theoretical maximum because the goal of OEE is to make losses, and specially those hidden losses, visible. Making them visible is the first step on overcoming the losses! Hiding them away between excuses like ‘this is not realistic’ closes the road for improvement…