What Is OEE (Overall Equipment Effectiveness)? A Guide to Understanding and Improving Production Efficiency

Table of Contents

• Introduction to OEE
• How to Calculate OEE?
• OEE, Q, P, and A Calculator
• Benefits of OEE Monitoring
• Breakdown of OEE
• Conclusion
• Practical Use of OEE
• The Role of TPM in Improving OEE

Introduction to the OEE (Overall Equipment Effectiveness)

The OEE (Overall Equipment Effectiveness) is a fundamental indicator for evaluating the efficiency of your machine, a production line or even your manufacturing workshop as a whole. Expressed as a percentage, it varies from 0 to 100%: a score of 100% indicates fully operational equipment, while a score of 0% means that no good part has been produced.

According to standard NF E60-182, OEE is defined as the ratio between useful time and required time. In other words, it measures the percentage of time spent producing good parts at rated rate compared to the time the equipment was available for production.

How to calculate the OEE ?

Alternately, The OEE can also be calculated as the ratio between the number of good parts produced and the number of parts that it would theoretically be possible to produce during the production time.

More specifically, the OEE can be broken down into three sub-indicators: it is the product of the Quality Rate (Q), the Performance Rate (P) and the Operational Availability (A).

OEE = Q × P × A

These three sub-indicators provide a more detailed view of production performance.

Quality Rate (Q): It represents the proportion between the number of quality parts produced and the total number of parts produced. If you've produced 90 quality parts out of 100, then the Q is 90%.

Performance Rate (P): It's the proportion between the actual production speed and the theoretical production speed. If a machine can theoretically produce 100 parts per hour but actually produces 80, then the P is 80%.

Operational Availability (A): It's calculated by dividing the actual operational time of the machine by the available production time. If a machine operates for 8 hours in a 10-hour day, then the A is 80%.

OEE, Q, P, and A Calculator

This calculator helps you determine your Overall Equipment Effectiveness (OEE), Quality Rate (Q), Performance Rate (P), and Operational Availability (A) based on your input data such as the number of conforming products, the total number of products, actual and theoretical cycle times, actual production time, and opening time. Simply enter your data in the fields below and click “Calculate” to get your results.

Actual Cycle Time (in minutes): This is the average observed time currently taken to produce a product or complete a production cycle. This time can be influenced by factors such as machine stoppages or performance losses due to minor interruptions or deviations in rates.

Theoretical Cycle Time (in minutes): This is the ideal or expected time to produce a product without any interruptions or inefficiencies. This would be the cycle time if there were no scheduled stops, organized malfunctions, or series changes.

Actual Production Time (in hours): This is the total time during which production actually took place, taking into account any machine stoppages and organized malfunctions. For instance, if you started an 8-hour workday but had 1 hour of downtime and 1 hour of training (organized malfunction), the actual production time would be 6 hours.

Opening Time (in hours): This is the total planned time for production, before accounting for any stops or interruptions. This would include the operating time, scheduled stops, and any other time during which production could theoretically take place.

Benefits of OEE monitoring

The OEE is a performance indicator that allows production to be challenged. It is particularly useful when tracked on the bottleneck resource, i.e. the element that limits the workflow. Furthermore, it should be noted that OEE is the reference indicator for TPM (Total Productive Maintenance), a methodology widely used to optimize productivity.

Breakdown of OEE

Useful time, net time, operating time, required time, open time, and total time are all important elements in understanding and calculating OEE . For example, the net time is obtained by adding to the useful time the non-quality time, which represents the time theoretically spent producing bad parts.

To obtain the operating time, the differences in cadence are added to the net time. These deviations represent the time lost in producing at a rate lower than the nominal rate.

The required time is calculated by adding the unplanned stops to the operating time. These stoppages, which are often the main cause of OEE losses, represent the time spent in stoppage by the installation.

OEE = Tu / Tr

Conclusion: The Importance of OEE in Improving Production

In summary, OEE is a key indicator that, when properly analyzed and interpreted, can provide valuable insight into production performance and enable improvement measures to be put in place. For any production manager, the use and understanding of OEE is essential.

Tracking this metric helps quickly identify inefficiencies and production issues, and determine what actions need to be taken to improve performance. Whether in terms of quality, performance or operational availability, every aspect of production can be optimized through the use of this indicator.

The use of OEE in practice

In practice, OEE monitoring can help identify various issues such as production defects, unplanned shutdowns, and supply or personnel issues. Identifying and resolving these issues helps improve production efficiency and maximize yield.

Additionally, the OEE can be used to track the progress of continuous improvement initiatives, and to identify areas where additional investment in equipment or staff training can be beneficial.

The role of TPM (Total Productive Maintenance) in improving OEE

TPM is a methodology that aims to maximize the efficiency of production equipment. It includes a set of tools and techniques that, when used in conjunction with OEE, can help reduce downtime, increase product quality, and improve overall production efficiency.

Finally, let's not forget that the OEE is not only a tool to assess current performance, but also an indicator that, when monitored over time, can help anticipate future problems and develop strategies. proactive to improve production efficiency.

It is important to understand that the objective is not to achieve 100% OEE at all costs, but rather to aim for continuous improvement and to optimize productivity and quality in a sustainable way. With the OEE as an ally, every company can set out on the path to manufacturing excellence.

To go further in optimizing your productivity, we invite you to consult our file model: OEE Dashboard for calculating the OEE and monitoring the performance of your production line. You can also watch our demo video below to understand in more detail how to effectively calculate and interpret OEE. These resources will help you put what you've learned into practice and take action to improve your production performance.