How Is OEE Calculated?

Sepasoft MES Module Suite

How is Overall Equipment Efficiency (OEE) Calculated?

OEE is measured against a production timeframe: a run/shift, or calendar time for a Line or Cell Group. OEE defines three performance indicators for Quality, Performance and Availability and each indicator is expressed as a percentage or decimal as a value.

OEE calculations output three performance indicators:

  • The Quality indicator is the percentage of acceptable units produced during defined production timeframe.

  • The Performance indicator is the percentage of a production timeframe that equipment is running at the designed or desired production speed.

  • The Availability indicator is the percentage of time within a production timeframe that equipment is ready for a production run and can be used.

OEE Indicator: Quality

The Quality indicator is calculated with the Infeed counter values and a Reject count.

(OEE Infeed Count - OEE Reject Count) / OEE Infeed Count = OEE Quality | Percentage of acceptable units produced

Success

It is important to note that Reject-Count values are calculated one of two ways depending on the system design.

When:

  • Reject counters have been added to equipment: in this case, all of the values for those counters are summed.
  • Reject counters have not been added to equipment: in this case, the value is derived from the difference between Infeed Counter and the Outfeed Counter on a line.

OEE Indicator: Performance

The Performance indicator is calculated with a count value of Infeed counters and a derived valued called 'Infeed Standard Count'. The Infeed Standard Count takes a Package Count and a production timeframe called 'Runtime'.

The Performance indicator is calculated with two variables: OEE Infeed Count and Infeed Standard Count:

OEE Infeed Count / Infeed Standard Count = OEE Performance | Percentage of a production timeframe that equipment is running at the designed or desired production speed

OEE Infeed Count

The variable OEE Infeed Count is is the sum of Infeed Counters.

Infeed Standard Count

The factor: Infeed Standard Count is calculated by three variables: Runtime, Standard Rate and Package Count. The variable 'Runtime' is a calculated value from planned and unplanned downtime of equipment. The variable 'Standard Rate' is a value that the system designer sets in the Rate Period settings.

Runtime * Standard Rate * Package Count = Infeed Standard Count

Runtime

'Runtime' is derived from the current production time and planned/unplanned downtime where production time is in the run state (Runtime = Elapsed time - Downtime: see Elapsed Time below)

Standard Rate

'Standard Rate' is a value that you configure in the Rate Period settings. For reference, see OEE Material Production Settings > Rate Period.

Package Count

'Package Count' is a value that you can configure to determine how many units make up a bundle of units. For reference, see OEE Material Production Settings > Package Count.

OEE Indicator: Availability

The Availability indicator is the percentage of time within a production timeframe (based on material information or work orders) that equipment is ready to use.

Runtime / (Elapsed Time - Planned Downtime) = OEE Availability | Percentage of time that equipment is ready for production

Elapsed Time

Elapsed Time means the time of current operation.

 





Sepasoft MES Module Suite