OEE - Calculator

Total available time during the week (all shift-hours) Hours
Total downtime including scheduled and unscheduled maintenance, set-up times, lack of personnel, meetings... Hours
Theoretical maximum output per hour (Ideal Run or Cycle Time in bottleneck) (output per hour)

Total Production during the period (Actual output)  
Output that had to be re-worked or scrapped  


Use this form for estimation.

Take a specific period (for example, a week or a month) and change the default values in the form.

Follow the example used as the default values in the form: The press-line at Example Ltd. schedules 76 shift-hours per week.

During Week #42, about 8,200 articles were produced, but 35 of them failed to pass quality control. The press-line, for different reasons, has not been running for 18 hours during the week. The theoretical maximum output is 200 articles per hour.

What is Overall Equipment Effectiveness ?

O.E.E. is a means to numerically describe production effectiveness, the ability to produce good product. Within OEE are characterized the three key production losses (i.e., availability, performance and quality)—and used to measure actual improvements on 5S, WCM, Lean Manufacturing, TPM.

After all factors are taken into account, the result is converted (transmuted) in percentage. The results (in %), therefore, can be regarded as a preview of the existing production efficiency of a particular line, cell or machine.

Having the right metrics, Overall Equipment Effectiveness provides you a window to analyze out-of-the-ordinary issues and gives you an established framework for improving the whole manufacturing process.

The tool helps you to methodically assess the process and to set a target. The vision, OEE=100%, will (probably) never be achieved, so improvements will always be possible.

One good thing about using Overall Equipment Effectiveness is that it cannot be manipulated as it is based on actual production that is compared to what was theoretically possible during the same period. This means that it allows companies to have separate business functions (production, maintenance, engineering e.tc) striving for a single, common goal. This is one reason why it is used in Lean Manufacturing.

Overall Equipment Effectiveness is a very effective benchmarking tool in making sound management decisions.

Useful Formulas:

OEE = Actual output / Theoretical maximum output = Availability Ratio x Performance Ratio x Quality Ratio

• Availability Ratio — The share of the actual production time and the planned production time. All planned stops and breakdowns will reduce the availability ratio, including set-up times, preventive maintenance, breakdowns and lack of operators. The only time that you may choose to deduct from the availability ratio is lack of orders.

• Performance Ratio — Loss of production due to under-utilization of the machinery. In other words, losses are incurred when the equipment is not run with full speed. Short, unregistered, stops may affect the performance ratio as well.

• Quality Ratio — The amount of the production that has to be discharged or scrapped.

By Oskar Olofsson

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Oskar Olofsson

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