What is OEE?

A light in the dark for mining and manufacturing

· 3AG blog,analytics

OEE. It’s a term almost everyone in mining and manufacturing is familiar with, but one that very few would profess to truly understand. Its application seems almost too simple, yet its calculation can stump even the brightest leaders.

An OEE definition and some broad applications

OEE, or overall equipment effectiveness is like the headlamp on a miner’s helmet: It shines a bright light where you need to focus your work and highlights how best to do that work—so you can be as efficient (with your time and other resources) as possible.

OEE is frequently employed across mining and manufacturing. Part of its appeal is its obvious usefulness; it simply shows what percentage of your manufacturing time is productive. A score of 100% means you’re producing good products as quickly as possible.

To expand a little, OEE measures how many good products an organization creates in a given timeframe divided by how many it theoretically could have produced if all machines and processes ran perfectly. It can be calculated by looking at actual production for a time period (tons, units, etc.) or by measuring the “good” time that equipment is running. This flexibility in measurement is both a blessing and a curse, as any site superintendent can tell you.

Regardless of such minor variations, OEE relies on elementary mathematics; for example, if your production line is designed to create 1,200 units per shift but only 900 are completed, your OEE score is 75%. Or, say, your mill can crush 5,000 tons every shift but only 3,000 tons are produced, your score would be 60%.

Its broad applicability has made OEE a valuable standard for determining productivity in manufacturing. OEE is usually broken down into three ratios, regardless of industry:

Availability compares equipment run-time against shift length. This may be affected by scheduled maintenance, unexpected breakdowns, staffing changes or disruptions, running out of supplies or supply chain interruption.

Performance looks at what is produced versus what could have been produced or how much time was spent producing units vs. total run time. This is usually affected by the relative health of the machine being measured.