In a world where competition is global, measuring the productivity of a production plant is one of the main needs for manufacturing companies.

Extricating between production targets, operator movements and maintenance operations is not easy and, without a synthesis indicator, you can risk to not have full visibility of the production process.

It is fundamental to understand what are the causes of downtimes or malfunctions and which are the phases of the production process that decrease efficiency. Having visibility on the processes is a fundamental requirement to carry out actions able to reduce production costs and therefore improve competitiveness on the market.

The indicators to measure the efficiency of a production plant are different. One of the most widespread is undoubtedly the OEE index. Let's see in details what it is, why it is important to know it and what are the precautions to measure it correctly.

The Overall Equipment Effectiveness

The OEE index, or global efficiency index, is an indicator that measures the efficiency of a machine, a plant or a factory. It provides operators with accurate information about the performance of the plant. It also has the advantage of being a standard indicator, an indicator that will be used as a reference for all the plans to improve production efficiency and effectiveness.

The OEE monitoring is usually an activity that is introduced on a specific machine, and then extended across the factory, with efficiency improvements of average 30-40%. For efficiency improvements we intend, as per manual, to increase production using same resources. The global efficiency index focuses on delays, production waste and interruptions. By reducing these three aspects will have significant benefits.


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The three dimensions of the OEE

How to calculate the OEE in a production facility? The index, expressed in percentage points, is calculated by multiplying three factors: availability, performance and quality.

Availability means the time when the production is actually on, with respect to the expected production time. In simpler terms, this index assumes a worrying value the more it diverges from 100%.

Performance means an indicator that identifies production losses due to a slowdown in production cycles. The index, calculated as a percentage, divides the actual production speed by the ideal speed in the specific phase of the process.

Lastly, the word quality indicates all the economic losses deriving from products that can not be marketed, as they do not comply with what is defined by the quality requirements. The index is calculated by dividing the number of compliant products by the total number of products processed.

By multiply these three factors, the OEE index will be a sign of greater efficiency, the closer it is to 100%. What can be considered a good result? It depends on the sector of reference. The values are generally considered a positive range from 85% up, but it must be considered that lots of production plants have been going on for decades with a global efficiency index of 60%.

How to increase the global efficiency index

One of the most immediate ways to increase OEE is to minimize unexpected downtimes, the only downtimes that actually impact the availability factor. To do this, it is necessary to deeply know what are the causes of these downtimes. The development of analysis on historical production data is needed, through appropriate IT tools. The analysis of these data could also lead to the discovery of many micro-downtimes, which may not even be accurately recorded, having a heavy impact on the production plant productivity.

To conclude …

Recording production data and being able to analyze it, is now a prerequisite for manufacturing companies. A good way to monitor processes is to measure the global efficiency index, a simple indicator that summarizes the negative effects resulting from downtimes, slowdowns or poor quality of products. The constant, accurate and real-time monitoring of this KPI requires the digitalization of the plant and new skills among the factory operators.

The OEE is just one of the indices that are utilized, perhaps the most famous, but probably not always adaptable to all types of production.

What is certain is that, in order to amortize investments and maximize the efficiency of a production plant, we must identify the most appropriate indicators, that can guide us in making decisions, and measure them accurately.


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