OEE Calculation-How To Calculate OEE (Overall Equipment Effectiveness) with Example
OEE Calculation-How To Calculate OEE (Overall Equipment Effectiveness) with Example:-
OEE Calculation is a simple calculation which is multiplied by availability, Performance and Quality. It is a methodology to measure the productivity of Process industries. If your manufacturing process OEE indicates 100%, It means you are Producing as fast as possible with low or no downtimes. Different types of losses are generally indicated through OEE, which also improves Manufacturing Productivity and Equipment health.
Download OEE Template (Excel sheet).
| OEE = A x P x Q |
| A-Availability P-Performance Q-Quality |
Availability:-
Availability = Run Time / Production Planned Time.
,(Run Time = Production Planned Time − Stop Time, Stop Time (or Downtime)=Unplanned or Planned Stops or both).
Stop Time is termed as the total time of Unplanned and Planned Stops or Total downtimes which may run the machine but due to the breakdown, the machine is unable to run.
Planned Stops are the total time taken due to Mould or tool changeovers, Preventive maintenance or First piece quality checking time etc.
Unplanned stops are the total time taken due to equipment or machine failure.
Performance:-
Performance = Ideal Time × Total Counts / Run Time.
It takes basically minor Stoppage, Slow cycle times or Reduced speed.
Quality:-
Quality = Good Count / Total Count
Common Losses in Industries:
| OEE | Common Losses | Details |
| Availability Loss | Unplanned stoppages | Equipment failure or machine failures |
| Planned stoppages | Mould changeover, Preventive maintenance, Set-up and adjustments | |
| Performance Loss | Small stoppages | Minor Stoppages |
| Slow Cycles | Speed reduction | |
| Quality loss | Production rejections | Defects of Process |
| Start-up Rejections | Defects of process |
Availability Loss:-
It is the total losses due to the Unplanned and planned Stoppages.
Equipment failure or Machine Failures:
Total downtime or stoppages due to Equipment failure or Machine Failures.
Any type of Tooling failure, Unavailability of alternative tools so that awaited time for alternative tools, breakdowns and unplanned maintenance, no operators, Shortages of raw materials, and Critical maintenance parts are the Potential causes of Equipment failure.
Setup and adjustments Losses (Mould changeover, Preventive maintenance):
Setup and Adjustment time is the total loss time of Mould/tools change over time, Planned maintenance time, cleaning time, and First Piece inspection times.
Performance Loss:-
It is the total Losses due to the minor stoppages and Slow Production Cycle times.
Minor stoppages:-
Minor stoppages are small downtime which takes a maximum of two minutes.
Material jams, obstructed product flow, Incorrect settings, misaligned or blocked sensors, and the Unintentional opening of safety Doors of machines are the Potential causes of Minor Stoppages.
Generally in TPM, those loss time to stoppages coming under the White tags are minor stoppages.
Speed Reduction:
Total loss time due to slow production cycles.
Quality loss:-
quality defects are the total loss time due to the Rework of Product, scrap and process PPM.
Defects of the process:
Defects of the process are the Total Scrap or PPM and The loss time for reworks.
How To Calculate OEE (Overall Equipment Effectiveness)
OEE Calculation is described here with Examples.
The below data are given for one shift only
| Item | Data |
| Shift Length | 8 hours (8*60=480 Minutes) |
| Breaks ( Tea and Lunch) | 50 minute |
| Downtime | 55 Minutes |
| Ideal Cycle Time | 1.0 Seconds |
| Total Production | 20000 Pieces |
| Reject Quantity | 320 Pieces |
| Availability | Performance | Quality |
| A= Run Time / Planned Production Time A=375 minutes / 430 minutes = 0.8720 (87.20%) Run Time=Planned Production Time − Stop Time Run Time=430 minutes − 55minutes = 375 minutes Planned Production Time =Shift Length − Breaks =480 minutes − 50 minutes = 430 minutes | P= (Ideal Cycle Time × Total Count) / Run Time P= (1.0 seconds × 20000 Pcs) / (375 minutes × 60 seconds) = 0.8888 (88.88%) | Q= Good Count / Total Count Q=19680 pcs / 20000 pcs = 0.9840 (98.40%) Good Count = Total Count − Reject Count =20000 Pcs − 320 Pcs = 19680 Pcs |
| OEE= A X P X Q =0.8720 × 0.8888 × 0.9840 = 0.7626 (76.26%) | ||
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