Why is my OEE 100% or above?

Why is my OEE 100% or above?

OEE theory states that: "an OEE score of 100% means that for the planned production time, the equipment is constantly working at optimum speed and produces only good quality products. There is therefore no downtime, short stops, loss of speed or defective products."

It is therefore highly unlikely that a normal factory production is actually running at 100% OEE, and above this is theoretically impossible. Why then do some production facilities see this in their data?

There are several possible reasons. Some of these are discussed here, although there will be others.

Reason 1: There may be genuine peaks in OEE.

If you are looking at the OEE calculation per hour on the KPI details graph for example, or another innius report, there may indeed be hours where 100% OEE was achieved. Although this would expected to be occasional, not normal.

Reason 2: The maximum machine rate has been set too low in the OEE configuration.

To calculate the Performance component of OEE, the theoretical maximum production rate needs to be defined. Refer to the Knowledge Base article: How do I configure the KPI: Overall Equipment Effectiveness?
This may be based on:
  1. The machine manufacturer's specifications.
  2. Previous experience of what the equipment together with operators can potentially achieve.
  3. A theoretical maximum based on the product type being produced.
For any of these factors, the maximum rating might have been determined as lower than it actually is. This may be by design, or perhaps in error. Or it may be for example, that the product type being run didn't match the product type defined in the OEE configuration.

Reason 3: Production is being counted whilst the machine is in downtime.

In cases where the Availability measurement is coming directly from the machine, it is sometimes desirable to configure the innius OEE to allow production to be counted when the machine is 'off'. This can happen in cases where the automated part of the production process finishes and is then manually finished, or perhaps defects are only counted up once the machine operation has finished. Either way, this setting can increase the actual machine production and rejection counts for the OEE calculation, which in extreme cases could cause the actual machine production to exceed the maximum production rate, resulting in a performance exceeding 100%.