O.E.E. calculation

A method of calculating the overall effectiveness of a production environment, you can use to measure and optimize the efficiency of both individual machines and whole plants.

You can measure, compare and contrast the overall effectiveness of individual or groups of identical machines performing a similar function.

Example

Three different schedules produce three different parts over an eight hour shift that includes two ten minute breaks and a five minute hand over period.

Shift Data

  Schedule A Schedule B Schedule C
Part Number Built A123 B456 C789
Cycle 10 seconds 45 seconds 70 seconds
Good Units Produced 2240 450 229
Scrap Units Produced 50 25 11
Unplanned Downtime 32 minutes 18 minutes 22 minutes
Scheduled Time 480 minutes (8*60) 480 minutes (8*60) 480 minutes (8*60)
Planned Down Time 25 minutes total 25 minutes total 25 minutes total
O.E.E. Schedule A Schedule B Schedule C
Net Available Time (NAT) 455 minutes (480-25) 455 minutes (480-25) 455 minutes (480-25)
Net Operating Time (NOT) 423 minutes 
(455-32)
 437 minutes 
(455-18)
 433 minutes 
(455-22)
Ideal Operating Time (IOT) 381.67 minutes 
((2290 units*10 seconds)/60)
 356.25 minutes 
(475 units*45 seconds)/60)
 280 minutes 
(240 units*70 seconds)/60)
Lost Operating Time (LOT) 8.33 minutes 
((50 scrap units*10 seconds)/60)
 18.75 minutes 
((25 scrap units*45 seconds)/60)
 12.83 minutes 
((11 scrap units*70 seconds)/60)
Availability 92.97% 
(NOT/NAT)*100
 96.04% 
(NOT/NAT)*100
 95.16% 
(NOT/NAT)*100
Performance 90.23% 
(IOT/NOT)*100
 81.52% 
(IOT/NOT)*100
 64.67% 
(IOT/NOT)*100
Quality 97.82% 
((IOT-LOT)/IOT)*100
 94.74% 
((IOT-LOT)/IOT)*100
 95.42% 
((IOT-LOT)/IOT)*100
O.E.E. 82.06% 
Availability*Performance*Quality
 74.17% 
Availability*Performance*Quality
 58.88% 
Availability*Performance*Quality

Where multiple products, or shifts are involved, you must apply weighting factors to the calculated results to produce statistically valid results.

  Availability
Schedule A 423 minutes
Schedule B 437 minutes
Schedule C 433 minutes
Total Net Operating Time 1293 minutes
Total Net Available Time 1365 minutes
Weighted 
1293/1365=94.73%
  Performance
Schedule A 381.67 minutes
Schedule B 356.25 minutes
Schedule C 280 minutes
Total Ideal Operating Time 1017.92 minutes
Total Net Operating Time 1293 minutes
Weighted 
1017.92/1293=78.73%
  Quality
Schedule A 8.33 minutes
Schedule B 18.75 minutes
Schedule C 12.83 minutes
Total Lost Operating Time 39.91 minutes
Total IOT 1017.92 minutes
Weighted 
39.91/978=96.08%

The weighted Overall Equipment Effectiveness is:

94.73*78.73*96.08=71.66%