How to do an OEE calculation

What is OEE?

Let’s start at the beginning: what is OEE? OEE (Overall Equipment Effectiveness) tells you how efficiently production resources are being used. How often does a machine halt? Why does it stop? What percentage of the maximum machine speed do you actually reach? Moreover, if you produce non-stop, at full speed, do you produce lots of waste? The power of OEE is that it clearly shows the most important instances of waste.

What does OEE measure exactly?

OEE measures the differences between ideal and actual production. When a production line operates 24 hours a day, produces at top speed, and delivers perfect quality, then we have an idea of the ideal line production. However, what is the actual output and what causes the differences? OEE focuses on three points:

• Machine availability
• Performance
• Product quality

A proper OEE calculation

A proper OEE calculation identifies where waste occurs in the process. That’s an invaluable step towards improving!

Start with an inventory

1. What’s the actual machine production? Look at availability, performance loss, and quality loss.
2. Then, make an inventory of all possible performance losses like short breaks in production because of machine malfunction, or when a product doesn’t run smoothly through the line. The inventory shows you the actual output of the machine.
3. Finally, make an inventory of all possible quality losses, or reasons for rejection (e.g., too thick, too small, the wrong color). How many good products remain?

When the percentages on actual production time, actual output and approved output are known, OEE can be calculated.

Availability x Speed x Quality = OEE

Loss or waste is also easy to calculate:

100% - OEE = Waste

The value of the OEE calculation

An OEE calculation is not an end but the means to an end: the OEE calculation in itself won’t get you very far. However, when OEE is known, you’ll be able to start improving and to measure the improvements. That’s an invaluable part of the improvement process!

OEE Software

Would you like to know why your production isn’t at its maximum capacity? Cierpa OEE examines the underlying reason for waste. Cierpa OEE combines manual, digital and real-time measurements into visual insight. By measuring alone you can expect a 3 to 5 % improvement immediately!