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17. Multi batch, parallel output, incl. rejects

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17. Multi batch, parallel output, incl. rejects

In this example

  • Shift time:                                       500 min
  • Production Run A:                         100 min
    •   Output 1                              45.000 Good (Set Speed 800 pcs/min)
    •                                                 5000 reject
    •   Output 2                               38 (Set Speed 0,6 pcs/min)
    •                                                  2 reject
  • Production Run B:                         10 min
    •   Output 3                                4.500 (Set Speed 700 pcs/min)
    •                                                   400 reject
    •   Output 4                                5 (Set Speed 0,6 pcs/min)
    •                                                   1 reject
  • Waiting:                                            390 min

Result

  1. Availability 22% (110min/500min)
  2. Performance: 45,9% (Weighted average!!)
  3. Quality: 91,7% (Weighted average!!)
  4. OEE = 22% x 45,9% x 91,7% = 9,3%

Calculation of Performance

  1. The quality of each product in a run is calculated:
    • First run:
      • 90%
      • 95%
    • Second run:
      • 91,8%
      • 83,3%
  2. The average performance for each run is calculated
    • First run: (90+95)/2= 92,5%
    • Second run (91,8% + 83,3%)/2 = 87,55%
  3. A weighted average is calculated for the different runs = 92%
    • 100 minutes at 45% and
    • 10 minutes at 54,5%:
    • ((100/110) * 45%) + ((10/110) * 54,5%) = 45,9%

Warning: Just adding all actual outputs and dividing this by all maximum outputs does not give a correct performance!

Calculation of Quality

  1. The quality of each product in a run is calculated:

First run:

  • 45000 Good/ (45000 Good + 5000 Reject) = 90%
  • 38 Good/(38 + 2 Reject) = 95%

Second run:

  • 4500 Good /(4500 Good + 400 Reject) = 91,8%
  • 5 Good/(5 Good + 1 Reject) = 83,3%

2. The average performance for each run is calculated

  • First run: (90+95)/2= 92,5%
  • Second run (91,8% + 83,3%)/2 = 87,55%

3. A weighted average is calculated for the different runs:

  • 100 minutes at 92,5% and
  • 10 minutes at 87,585%:
  • ((100/110) * 92,5%) + ((10/110) * 87,585%) = 92,05%

Warning: Also the quality rate is a weighted average! Just adding all good outputs and dividing this by all actual outputs does not give a correct quality rate!