OEE Metrics Calculations

Quality:

We select all running/downtime/switch phases that have been recorded for an asset. For all these phases, we sum up the total count of good product manufactured, and the total count of rejected products.

Quality = (Total Production - Total Rejected Products) / Total Production

Note: Calculating quality requires two sensors for the corresponding production line. If only one production sensor is installed, then the quality will be 100% by default.

Performance:

Performance takes into account speed losses, which includes any factors that cause the process to operate at less than the maximum possible speed when running. For each product linked to an asset, users can enter the expected run rate.

In order to calculate the asset performance, we first calculate what is the operating run time:

Run time = Total running time + performance downtime

Then we calculate the expected production by multiplying the run with the expected run rate:

Expected production = Run time * Expected run rate

This leads to the performance metrics:

Performance = Total Production / Expected Production

Availability:

Availability takes into account downtime losses (events that stop planned production for an appreciable length of time).

Availability is calculated as the ratio of operating real time over available production time:

Availability = Operating real time / Available production time

The available production time is calculated as:

Available production time = Total running time + availability losses + performance losses = Total running time + Total downtimes

Note that by default micro downtime are considered to be performance losses.

The operating real time is the total amount of time for which the asset was marked as running or in a performance downtime

Operating real time = Total running time + performance losses

To sum up, availability is calculated as:

Availability = (Total running time + performance losses) / (Total running time + performance losses + availability losses)