What is OEE?
Overall equipment effectiveness, also known as OEE, is a metric commonly used in industry to measure how well an operating line is running, making 1st grade product, compared to the theoretical productivity levels.
At a high level, it is a very easy calculation. As with other things though, the devil is in the details!
Simple OEE Calculation
The better way to look at it is to break OEE into Availability, Performance and Quality. When it is broken down into these components then it is possible to start looking at where the opportunities are to improve.
What are the Opportunities?
Availability
Operating Time
- Time the equipment is actually running – no downtime, no change over, no stoppages
Planned Production Time
- Total time in a day or shift minus break time, meeting time, planned downtime
Opportunity = reduce unplanned downtime, reduce time to do changeovers between lots, between products, between shifts
Performance
Ideal Cycle Time X Total Pieces
- Time to produce 1 piece at the maximum production rate the equipment can manage X total pieces produced in the operating time
Planned Production Time
- Total time in a day or shift minus break time, meeting time, planned downtime
Opportunity = reduce instances where the operations does not run at the peak rate, simplify process
Quality
Good Pieces
- Pieces that went through ALL steps of the process only once > no rework, no reprocessing, no returns, no rejects
Total Pieces
- Number of pieces produced in the operating time > including rework and rejects
Opportunity = reduce defects, simplify process, review raw material prior to starting process, good products the first time