Overall Equipment Effectiveness Definition & Calculation | eMaint

What is Overall Equipment Effectiveness (OEE)?

Overall equipment effectiveness (OEE) is one of the most important metrics to help organizations analyze and optimize equipment usage. OEE evaluates how available equipment is, how it performs and what kind of quality it produces. The metric offers an important, high level overview of equipment efficiency.

Why measure OEE?

OEE measurement is a common key performance indicator (KPI) for organizations across all industries. With lean manufacturing initiatives, benchmarking OEE can provide insight into maintenance successes, or help identify areas in need of improvement.

When you understand how effective your equipment is under the availability, performance and quality realms, it is easier to identify where to make specific improvements. For example, if your focus is on performance, you can closely monitor and analyze what is having the greatest impact on production output.

To further discover what is contributing to production losses, availability, performance and quality are subdivided into what is called the ‘Six Big Losses’ in OEE. They are categorized as:

How do you calculate OEE?

  • Availability = Run Time / Planned Production Time

Availability accounts for all events that stop planned production long enough to qualify and track as downtime.

  • Performance = (Ideal Cycle Time × Total Count) / Run Time

Performance takes into account anything that causes the manufacturing process to run at less than the maximum possible speed.

  • Quality = Good Count / Total Count 

Quality accounts for manufactured parts that do not meet quality internal or external standards, including parts that need rework.

To discover the total OEE for a particular piece of equipment, you multiply availability, performance and quality together:

How do you improve OEE?

OEE.com offers a simple “I.D.A” methodology to help drive improvements for OEE. I.D.A focuses on:

  • Information (I) – A key to begin making better-informed decision making is using accurate, relevant and easy-to-understand information.
  • Decision (D) – When information is tracked and reviewed, organizations are in a position to make decisions that will lead to productive action.
  • Action (A) – Action is a tangible process sparked from theoretical decisions, and Results (R) follow.