Overall Equipment Effectiveness (OEE)

Overall equipment effectiveness is a metric of how well planned production time is used, calculated as availability multiplied by performance multiplied by quality, so that 100 per cent means only good parts, at ideal speed, with no stops.

OEE compares what a machine, line or cell actually produced with what it could have produced in the time it was scheduled to run. Availability captures time lost to stops, performance captures speed losses against the ideal cycle time, and quality captures parts that were scrapped or reworked. Multiplying the three factors gives a single percentage. An equivalent calculation is good count multiplied by ideal cycle time, divided by planned production time.

The metric was popularised by Seiichi Nakajima as part of total productive maintenance and is now used widely in discrete and process manufacturing. Plants use OEE to expose hidden capacity, prioritise improvement projects, compare shifts and track the effect of maintenance and changeover work. Breaking OEE into its three factors points teams to the dominant loss, which is usually more useful than the headline figure.

Results depend heavily on definitions, such as what counts as planned downtime and how the ideal cycle time is set, so comparisons between sites are meaningful only with consistent rules. Manual data collection tends to under-report short stops, which is why automated counting from machine controllers is common. OEE covers scheduled time only; TEEP extends the idea to all calendar time. ISO 22400 defines key performance indicators for manufacturing operations management, including OEE.

Key points

OEE equals availability multiplied by performance multiplied by quality.
Equivalent form: good count times ideal cycle time, divided by planned production time.
Popularised by Seiichi Nakajima within total productive maintenance.
Consistent definitions of planned downtime and ideal cycle time are essential for comparisons.
ISO 22400 defines manufacturing operations KPIs, including OEE.

Where AiVibe comes in

AiVibe designs and manufactures the AiAmbA AI Factory as the OEM: edge devices plus AI agents that let people talk to PLC, CNC and robot controllers in plain language. Existing lines are retrofitted with edge devices, and a trained operator confirms every change an agent proposes.

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Overall Equipment Effectiveness (OEE)

Key points

Where AiVibe comes in

Related terms

Terms that refer to Overall Equipment Effectiveness (OEE)