FMEA stands for Failure Mode and Effects Analysis, a technique for reviewing subsystems, components, and assemblies to identify potential failure scenarios in a system. This tool also allows for investigating the causes and effects of these failure modes.

This approach offers a step-by-step paradigm for checking for possible defects in a product or service’s design or assembly process. “Failure modes” are the ways something can go wrong. This includes any current or potential defects, especially those affecting customers.

The “effects analysis” studies the consequences of these failures. Errors should be prioritized according to the severity of their effects, their frequency, and how easy they are to detect.

The evaluator should document the current knowledge and ongoing projects related to identified failures and risks. This should be used in the organization’s continuous improvement process, assisting in quality control before and after the regular operation of a given process.

FMEA Benefits

FMEA provides several benefits to organizations that use it, such as:

• Increases the reliability and safety of products and processes. By identifying potential or actual failures, FMEA allows for correcting or eliminating the causes of these failures, preventing them from recurring or getting worse.
• Reduces costs and waste. FMEA prevents or minimizes the effects of failures, reducing costs and optimizing resources.
• Improves customer satisfaction. FMEA delivers high-quality and reliable products and services, anticipating customer needs and expectations.
• Improves risk planning and management. FMEA analyzes and prioritizes failures, monitoring and evaluating improvement actions.
• Promotes continuous improvement. FMEA documents and records failures, learning from mistakes and applying best practices.

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Types of FMEA

Due to its flexibility, Failure Mode and Effects Analysis can be used in various contexts, resulting in different types of FMEA. The technique can be categorized in several different ways, but it is generally divided into three main classes: DFMEA, PFMEA, and SFMEA. Below, we explain what each element of this alphabet soup means.

Design FMEA (DFMEA)

Design FMEA (DFMEA) is performed during the product design phase. The goal is to improve the design of this merchandise by discovering potential problems.

To verify this, the following are evaluated:

• Properties of the materials used: lubrication, viscosity, elasticity.
• Product geometry: critical dimensions, interferences, ergonomics.
• Tolerances: assembly compatibility, functional performance, durability, and lifespan.
• Engineering noise: noise sources, noise levels, impact on performance.
• Other elements: safety, reliability, and durability, among others.

DFMEA is generally applied in the automotive and aerospace industries. In the case of automotive, manufacturers evaluate the design of a new vehicle to find potential failure points within critical components. For this, they usually check brakes, engine, and transmission.

In the aerospace industry, Design FMEA is used to analyze the design of an aircraft with a special eye on failure points related to safety and performance. The goal, of course, is to resolve them during the design phase.

Process FMEA (PFMEA)

PFMEA should be applied during the manufacturing or production of a commodity. It determines the search for failures that allow greater reliability and safety of your workforce.

For this, you need to evaluate factors such as human errors, analysis methods, materials, and machines used within your processes. It is also recommended to check your monitoring metrics and explore environmental factors.

PFMEA is generally used in industries where customer satisfaction is a crucial factor, such as the food industry. Food companies often use this process methodology to find potential failure modes in their manufacturing process.

These elements include things like contamination, improper handling, or packaging problems. This way, it is possible to identify the effects of these errors on food quality and consumer safety.

System FMEA (SFMEA)

Finally, we have System FMEA, represented by the acronym SFMEA. This is a more generalized analysis of systematic failures. We can describe it as a Design FMEA but for the entire system.

This technique is applied during the service or maintenance phases. The steps to apply SFMEA are basically the same as DFMEA, including function, failure, and risk analyses.

The main sectors that use the system FMEA are:

• Medical device industry: manufacturers of medical and hospital devices use SFMEA to find possible failure modes in the manufacturing or operation of their products. The procedure includes looking for incorrect calibrations and installation errors.
• Telecommunications industry: companies in the communication technology sector seek to find failures in their services. This includes things like network interruptions, billing errors, or customer complaints.

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How can FMEA be used?

FMEA is a method that makes us think: “if this failure happens, what are the consequences?” The goal is to reduce the chance of a failure occurring as much as possible, removing what causes it.

This tool works as a knowledge summary, which allows the creation of a record based on past experiences with similar products/processes and the use of this information for future improvements.

Using FMEA consistently prevents failures and makes the service safer and more reliable. This provides greater security and satisfaction to customers. In addition, it has a positive impact on the company’s financial return, as it reduces or eliminates potential failures in production processes.

How to Apply FMEA 

Now that you know what FMEA is and what types exist, it’s time to learn how to apply the technique in your organization. It is essential that the analysis is done in the right order and one step at a time, as each new step depends on the result of the previous one.

Step 1: Planning and Preparation

The FMEA study begins with a purposeful and careful definition of the scope. The management team is responsible for defining the study’s objective.

Step 2: Structure Analysis

Structure analysis is used to | into sequential steps, interfaces, and logistical elements. It uses the boundaries stipulated by the scope definition in step 1 to identify each step, interface, and logistical element of the process to be studied.

The goal of structure analysis is to facilitate a complete understanding of the process. Start with the central element of your scope, identify the process it is part of, and point out all elements that have a direct relationship with it.

Step 3: Function Analysis

In the Function Analysis step, you should explore what the product should do, what the overall process (and each of its activities) should perform, and how this functionality is facilitated. Using the Structure Analysis developed in step 2, each element is analyzed separately in terms of functions and corresponding requirements.

Step 4: Failure Analysis

In step 4, the concept of the “failure chain” is used to understand and visualize imperfections in the process. This chain is composed of mode, effect, and cause of failure.

• Failure mode represents any way an item can fail to meet its intended function.
• The failure effect is the consequence of a failure mode.
• Failure cause is an indication of what can make a failure mode happen.

In failure analysis, you identify how the elements detailed in Structure Analysis can present errors in performing the intended functions — which are documented by Function Analysis. A failure mode leads to an effect triggered by a failure cause. Determining possible causes is the central element of an FMEA.

Step 5: Risk Analysis

In step 5, you should evaluate the severity, occurrence, and detection capability of each failure chain. Based on the evaluations, determine the level of action priority between “high, medium, or low.”

Use the Action Priority Tables as a basis. It is worth noting that these tables do not establish a “risk priority,” but a level of priority for the demanded action. This seeks to reduce the risk of functional failure.

If the evaluated level is high, measures must be taken to improve prevention or detection controls. Otherwise, you should at least justify what makes the current controls adequate.

If the level is medium, it is recommended that measures be taken to improve prevention and/or detection controls. If it is low, actions to improve prevention or detection controls can be taken but are not mandatory.

Step 6: Optimization

The main objective of the optimization stage is to develop actions to reduce risks and increase customer satisfaction by improving your processes. Most actions will likely involve reducing the probability of occurrence of failure causes or improving detection controls. Both alternatives lead to a more robust process.

Step 7: Documentation of Results

The results of each FMEA study must be fully documented. An FMEA study will not be complete until Step 7 is finalized.

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FMEA Example

Below is a detailed step-by-step on how to conduct an FMEA. Please remember that this is just a simple and didactic example to make it easier to understand.

1. Process step

Let’s consider the process of testing a finished car at a car manufacturer plant.

2. Failure mode

In this FMEA example, we defined two failure modes:

• The car does not brake
• The car does not start

3. Failure effect

So, we ask the question: “If this failure occurs, what could happen?”. We have as effects of these failures:

• Accident
• The consumer would be unable to reach their destination

4. Severity (S)

As the accident is the worst possible scenario, we rate the severity value as 10 and for the second effect, not so serious, we rated it as 7.

5. Failure causes

“What could cause these failures?” We list two probable causes for each failure mode:

• The brake system not working or the wheels slipping during the test.
• Battery problem or fuel shortage.

6. Probability of occurrence

As it is a new car that just left the manufacturer, we consider:

• Probability of occurrence 7 (high) for the probability that the problem is in the brake system and 2 (low) for the problem to be in the wheels.
• The probability of occurrence is 5 (moderate) for the problem in the battery and 3 (low) for fuel shortage.

7. Process controls

As mentioned earlier, process controls can prevent the cause or detect it after it has occurred. In this case, the indications we have for problems are:

• In the brake system would be noise. Brake pads emit different types of noise and each of them represents a different failure. These include high and low-frequency squeal, judder, groan, moan, rattle, clack, chirp, and creak. That is, a fully functioning brake system ideally does not make noises.
• Another control would be the TWI (Tread Wear Indicator), which measures the thickness and depth of the tire grooves.
• The car’s dashboard works as a control to detect both the battery and fuel shortage problems.

8. Detection (D)

The lower the detection value, the greater the chance of detecting the failure. We have the following detection scores:

• Brake noise as 2 for extremely likely to be heard and 3 for tread wear indicator.
• Battery problem as 1 and fuel shortage as 4.

9. Risk Priority Number (RPN)

Finally, we calculate the RPN. The higher the RPN value, the higher the priority of that item in the preventive action plan.

In this example, the highest number was for the first failure mode (the car does not brake), which means that verifying it should be the automaker’s priority for improvement.

FMEA Results

After finishing the FMEA, what to do with the results?

This last step is the most important, and if not done correctly, all previous steps will be irrelevant to your product or process.

After finishing the FMEA, we use the results to:

• Mitigate high-risk failures.
• Reduce the severity of consequences and probability of occurrences.
• Add controls to increase failure detection.
• Create action plans with dates and people responsible for implementing each improvement.
• Reassess to ensure objectives are achieved.

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Conclusion

The implementation of FMEA (Failure Mode and Effects Analysis) is a fundamental step to ensure the quality and safety of products and processes in an organization. By identifying and evaluating potential failure modes, as well as their causes and effects, companies can proactively act to mitigate risks and increase customer satisfaction.

Through its different applications, such as DFMEA, PFMEA, and SFMEA, the technique provides a systematic and detailed approach to failure analysis at various stages of the product or service lifecycle.

Thus, FMEA not only helps identify problems before they occur but also provides a solid foundation for continuous improvement, making it an indispensable tool for any organization seeking operational excellence.

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