OEE: learn about this indicator of efficiency in industries

Have you ever noticed that in factories around the world, there's always talk of some kind of OEE? It's kind of the main star when it comes to measuring production performance. But do we really know what OEE is and how to use it to boost factory performance? Let's dig a little deeper into this subject and discover the tricks of this indicator!

OEE, que vem do inglês Overall Equipment Effectiveness, ou Eficácia Geral do Equipamento em português, nascido com intenção de auxiliar o TPM (Manutenção Produtiva Total). é considerado o padrão de ouro para avaliar a produtividade na fabricação. É um conceito central na manufatura enxuta e um indicador chave de desempenho para qualquer instalação de produção, unidade fabril ou estação individual.

The great thing about OEE is that it's not just a pretty number for us to admire. It's here to make a real difference, pointing out where production needs help and how we can improve.

Mas claro, não basta só ter o OEE na manga e esperar a mágica acontecer. Implementar isso direito é um processo que requer organização e ter um time alinhado é crucial. Tem que ter os dados certos em mãos, entender os princípios básicos e, principalmente, os benefícios que isso traz pra empresa.

OEE acts as a problem detector in production, revealing faults along the line and in the machines, what is often referred to as the "hidden factory". It shows where we are missing production opportunities with the resources we have available.

Além disso, o OEE orienta as estratégias de alocação de recursos e manutenção ao destacar os problemas reais dentro da fábrica. Ao concentrar esforços na eliminação de desperdícios, o OEE não apenas mede o desempenho, mas também impulsiona a busca pela melhoria contínua. Podemos ir mais além, se você tiver o OEE em tempo real, conectado a uma ferramenta de APS (advanced planning & scheduling), poderá prever se vai cumprir as ordens de produção e ajustar a entrega de clientes e ainda, antecipando problemas ou reclamações, você estará levando sua empresa para outro patamar de informação.

The interesting thing about this indicator is that it focuses on the critical areas of lost productivity, grouped into three main categories: availability, performance and quality. These categories are fundamental to understanding how factory equipment is used and how products are delivered to customers.

But how do we calculate this OEE? Well, OEE is the result of multiplying three parts: availability, performance and quality. I'll explain what each one means and how to calculate it:

Availability

‍Thisis how long the machine or production line was available to work as planned, without any unscheduled stops. To calculate this, we look at the total time the machine or line was supposed to be working and subtract the time it was stopped for some reason. The reasons can be planned or unplanned stoppages: explain the planned ones, which are missing from the text.

As paradas não planejadas são quando a máquina para inesperadamente, sem a gente ter programado. Pode ser por quebra de equipamento, falta de operadores ou até falta de material. Já as paradas planejadas são aquelas que sabemos antecipadamente  que ia acontecer, como  manutenção, ajustar alguma ferramenta ou até limpar a máquina.

It's important to remember that the list of reasons for downtime can vary depending on the type of production and the company. But a good way to get started is to write down the most common causes of downtime.

E tem mais uma coisa: não se conta como perda de disponibilidade as paradas já  programadas, como grandes manutenções planejadas (como aquelas de fim de ano, por exemplo) ou reformas. E também não conta devemos contar quando a falta de demanda ou alguma sazonalidade determina que fechemos alguns turnos completos previamente. que acaba deixando a máquina sem programação de produção. Estes são excluídos do cálculo do OEE. Por outro lado, tempos de setup e espera por produção de outros setores para produzir são contabilizados

Performance

‍Herewe are looking at the actual speed of the machine or production line compared to the speed that has been predicted. This predicted speed, sometimes called the "maximum demonstrated rate" (MDR) or "ideal cycle time", represents the maximum that the machine should be able to produce.

The performance shows how much the machine actually yielded during the time it was running, compared to the maximum it could have yielded operating at that maximum speed.

We divide performance losses into two types:

Micro-stops: These are moments when the machine stops for a short period, usually less than a minute. Often the operator can solve the problem quickly. However, these stops can be so frequent that their impact can go unnoticed. Examples include feed failures, material jams, misconfigurations and even quick clean-ups that need to be done occasionally.

Slow cycles: These are times when the machine runs slower than the expected speed. This can be caused by various reasons, such as the machine being dirty or worn out, inadequate lubrication, inferior material or incorrect settings. Human factors, such as the operators' lack of training or experience, can also influence this.

Quality

‍Thethird aspect of OEE focuses on the quality of the products manufactured. In simple terms, quality refers to the percentage of products that leave the production line according to the customer's specifications the first time. Quality losses are divided into two categories: production rejects and initial rejects.

Production rejects: These are defects that arise during stable production, i.e. when the line is running smoothly. These defects can be corrected through rework. For example, products with incorrect weights, labeling problems, chemical or physical non-conformities and damaged packaging.

Initial rejects: This includes defects that occur from the start of production until the line stabilizes. These defects are usually more noticeable after shift changes or when equipment starts operating. Examples include non-standard products, equipment that needs time to warm up or that generates waste at the start of operation.

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To make it easier to understand how to put all this together in a formula, we've created the example below so that you can better understand and calculate your OEE. Take a look:

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Importantly, each of these pillars of the OEE calculation has some common mistakes that we must be careful not to miscalculate, distorting the indicator.

See examples below:

Availability:

Availability is an area where many challenges arise when calculating OEE. A common mistake is to exclude too much downtime from the OEE calculation.

For example, shift changes are often omitted from the calculation, even though they represent significant periods of inactivity. Imagine a changeover that lasts 30 minutes when it was only scheduled to last 10 minutes. This results in a loss of 20 minutes in the process, which can considerably impact production. Identifying and understanding these losses is crucial to improving operational efficiency.

Performance:

A common performance-related challenge is a lack of understanding of the maximum potential output of machines. Manufacturers often underestimate the actual production speed, which can lead to an incorrect OEE reading, with a performance percentage of more than 100%.

One way to solve this is to contact the machine manufacturer for information on the maximum demonstrated rate (MDR). If this is not feasible, it is possible to establish a reference based on records of the fastest changes. Periodically adjusting cycle times based on operator performance can also help improve the accuracy of the calculation.

Quality:

With regard to quality, two main challenges arise when calculating OEE:

The lack of a reliable method for automatically recording scrap, which often requires operators to manually record rejects.

The delay in obtaining quality information, which can result in inaccurate data when calculating OEE retrospectively.

Resolving these issues is essential to ensure that the OEE calculation accurately reflects the efficiency and quality of production operations.

Understanding and implementing OEE is key to setting achievable targets and optimizing equipment utilization. Following a successful implementation guide ensures that you are on the right track to achieving your lean manufacturing goals.

Now that we have a better understanding of what OEE is, how can we start implementing it in real time in our company? At NEO, we are experts in this field and have helped companies all over the world reach their full potential. To make this journey even easier, we're offering you 30 free days of our OEE tool, along with the hardware needed to connect to your equipment and transmit the signals (yes, you read that right! 30 days with the equipment at no cost!). And before you ask about any catches or fine print, know that if you don't like it or it doesn't suit your process, simply return the equipment. It's as simple as that, because our mission is to help the industry reach its full potential.

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