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20. Multi batch, parallel output,  multiple rejects

In this example

  • Shift time:                                       500 min
  • Production Run A:                         100 min
    •   Output 1                                  45.000 Good (Set Speed 800 pcs/min)
    •                                                     5000 rework + 1000 scrap
    •   Output 2                                  38 (Set Speed 0,6 pcs/min)
    •                                                      2 rework + 3 scrap
  • Production Run B:                         10 min
    • Output 3                                       4.500 (Set Speed 700 pcs/min)
    •                                                        400 scrap + 150 rework
    • Output 4                                        4 (Set Speed 0.9 pcs/min)
    •                                                         1 rework + 2 scrap
  • Waiting:                                            390 min

Result

  1. Availability 22% (110min/500min)
  2. Performance: 48,2% (Weighted average!!)
  3. Quality: 86,28% (Weighted average!!)
  4. OEE = 22% x 48,2% x 86,28% = 9,15%

Performance Calculation

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

First run:

  • (45000 good + 5000 R + 1000 S) /100.000 max = 51%
  • (38 good + 2 R + 3 S)/100 max = 43%

Second run:

  • (4500 good + 400 S + 150 R)/10.000 max = 50,5%
  • (4 good + 1 R + 2 S)/10 = 70%

2. The average performance for each run is calculated

  • First run: (51+43)/2= 47%
  • Second run (50,5% + 70%)/2 = 60,25%

3. A weighted average is calculated for the different runs

  • 100 minutes at 47% and
  • 10 minutes at 60,25%:
  • ((100/110) * 47%) + ((10/110) * 60,25%) = 48,2% performance

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

Quality Calculation

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

First run:

  • 45000 Good/ (45000 Good + 6000 Rejects) = 88,23%
  • 38 Good/(38 Good + 5 Rejects) = 88,37%

Second run:

  • 4500 Good /(4500 Good + 550 Rejects) = 89,1%
  • 4 Good/(4 Good + 3 Rejects) = 57,14%

2. The average quality-rate for each run is calculated:

  • First run: (88,23 + 88,37)/2= 88,3%
  • Second run (89,1% + 57,14%)/2 = 73,12%

3. A weighted average is calculated for the different runs. For a correct result this is to be done in time:

Good product time, first run:

  • (100min / 2) * ( (45000 / 100000) + (38 / 100) ) =
  • 50min * (0,45 + 0,38) = 41,5 min

Good product time, second run:

  • (10min / 2) * ((4500 / 10000 + (4 / 10)) =
  • 5 min * (0,45 +0,4) = 4,25 min

Total good product-time:

41,5 min + 4,25 min = 45,75 min Good time

Quality Rate:

(45.75 / 53.025) * 100 = 86.28%

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