TPM method

Overall Equipment Effectiveness (OEE)

The Overall Equipment Effectiveness (OEE) refers to a production-related metric for determining the value creation of a facility.

An ideal machine would run continuously, always at maximum performance, and without any defects. However, this ideal scenario rarely occurs in reality. The Overall Equipment Effectiveness (OEE) serves as a metric to determine how close the equipment is to this ideal state. It combines time, quantity, and quality to provide an effectiveness assessment.Starting with the maximum available time, for example, assumed to be 24 hours, the theoretically available production time is used as the basis for further calculations. This potential production time is derived from the total time in the observation period minus all planned downtimes, such as maintenance, repairs, or non-utilization of the equipment due to the order situation.Three types of losses are distinguished for OEE calculation:
  • Availability losses
  • Performance losses
  • Quality losses
Availability losses: These occur due to unplanned downtimes during the potential production time, such as breakdowns, setup processes, or waiting times. Subtracting availability losses from the potential production time yields the actual production time.Performance losses: These represent the difference between the potential output of the equipment based on the actual production time and the actual output. This difference arises from short stoppages, such as jammed parts, or from reduced equipment speed.Quality losses: These include all non-conforming products produced by the equipment. Any product requiring rework or considered scrap is deducted from the actual output for calculating the OEE.Overall, the OEE is calculated by multiplying the availability rate (actual production time / potential production time) by the performance rate (actual output / potential output) by the quality rate (good products / actual output).

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OEE Excel Tool

Discover for yourself how OEE is precisely calculated and conduct an assessment in your manufacturing today.
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An example of how optimized maintenance can affect the OEE:

Example 1: High production time, lower quality

Available time (24 hrs)

– Planned downtime

Availability

A: Possible production time 95%

– Availability losses:
Breakdowns, Setup and Adjustment Time, Line Constraints

B: Actual production time 80%

Performance

C: Possible Output 80%

– Performance losses:
Short Stops, Reduced Speed

D: Actual output 70%

Quality

E: Actual output 70%

– Quality losses:
– Scrap, Rework

Q: Impeccable products 60%
Degree of availability (B/A) x performance level (D/C) x quality rate (F/E)
0 % OEE

Example 2: More planned maintenance, lower failure rate

Available time (24 hrs)

– Planned Downtime

Availability

A: Possible production time 85%

– Availability losses:
Breakdowns, Setup and Adjustment Time, Line Constraints

B: Actual production time 80%

Performance

C: Possible output 80%

– Performance losses:
Short Stops, Reduced Speed

D: Actual output 75%

Quality

E: Actual output 75%

– Quality losses:
– Scrap, Rework

Q: Impeccable products 70%
Degree of availability (B/A) x performance level (D/C) x quality rate (F/E)
0 % OEE