Availability Loss

This means the machine is not running when it should, leading to less production time = Unplanned Downtimes, such as Machine Breaks, no material, etc.

It is important to clarify that Schedule Loss or Planned Downtime are not included in the OEE calculations as they are part of  OOE(Overall Operations Efficiency).

In this example, the line was active for only 20 hours of the 32.5 hours that is supposed to be running according to its Scheduled time. The Scheduled time takes into account Planned downtimes such as Lunch, Breaks, etc.

With those 20 hrs, the line could only produced 400 units of the 650 that could have been produced if there hadn't been any unplanned downtimes.

How to calculate Availability losses

The calculation depends on the KPI you're focusing on. For OEE, Availability considers only Unplanned Downtimes, while for OOE, it factors in both Unplanned and Planned downtimes. TEEP, on the other hand, incorporates a continuous 24/7 Maximum Time for its calculation.

Performance Loss

When the machine operates at a slower speed than its ideal or designed speed. This means it takes longer to produce each unit, reducing efficiency = Slow cycles and Micro stops.

In this example the line instead of running at a 20 units/h Rate it ran to 16 units/ h, as a result, it only could produce 320 units of the 400 units that it would have produced running at the targeted rate.

Quality Loss

When not all produced units meet the required quality standards, scrap and parts that need rework.

In our example, there were 35 units rejected at the Quality check process.

When any of OEE's factors (Availability, Performance, and Quality) falls below 100%, it signifies a loss that can be quantified in terms of time, units, and money.

In this example, the amount net units, or good counts left were 285 units of the 650 units that could have been produced, without unplanned downtimes at the right speed, with no rejects.

By diligently monitoring and optimizing these factors, you can make significant improvements at every stage of your production process, leading to increased efficiency and cost savings.

OEE Benchmarks

Seiichi Nakajima introduced the concepts of OEE and total productive maintenance (TPM) in the 1970s, and in his 1984 book Introduction to TPM, he suggested four “world-class” numbers: availability of 90 percent, efficiency of 95 percent, and quality of 99 percent, yielding 85 percent (world-class) OEE

• 100% OEE is considered perfect production
• 85% OEE reflects world-class operations
• 60% OEE is typical and average
• 40% OEE is low but not uncommon

The metric could have different weights depending on your industry, type of company, size, etc.

There are times when a world-class OEE target is either unrealistic or unideal, simply because of how your operations work. Distinct differences exist between manufacturers of large and small product mixes, based on their target numbers for the individual aspects of OEE (availability, efficiency, and quality).

When should you track OOE and when OEE?

The key difference among these metrics lies in defining Availability. Each aims to assess actual production (OEE) versus potential production (OOE), depending on the timeframe.

Therefore, a company should measure OEE when they need detailed insights into equipment performance and efficiency, whereas OOE is more appropriate when they want to evaluate overall operational effectiveness and identify opportunities for holistic improvement across multiple aspects of their operations.