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%