Thinking based on anticipating failures has been around for hundreds of years, but the first widely known use of FMEA (Failure Modes and Effect Analysis) was in the 1940s. The US military developed this technique to reduce sources of variation and potential failures in the production of ammunition.
With proof that the military had been able to reduce project risks with the use of FMEA, the aerospace industry also adopted this methodology for the Apollo missions and other subsequent NASA missions.
In the late 1970s, the use of FMEA took off in the automotive industry due to the advantages it offered to reduce risks related to quality. In 1993, the AIAG (Automotive Industry Action Group) incorporated FMEA into the QS9000 standard for automotive production and for its suppliers. QS9000 later became TS16949 and then IATF16949, as of November, 2016.
FMEA has proven to be crucial as a planning technique and it is widely used today in all kinds of industries to ensure the safety and efficiency of products and processes.
What is FMEA?
Failure Modes and Effects Analysis (FMEA) is a tool used to assess the reliability of systems and identify potential failures in projects, processes, products or services. With FMEA, it is possible to define a plan to proactively correct these potential failures and thus avoid their negative effects.
FMEA is an inductive method in which we ask ourselves: “if this failure occurs, what could happen?” The idea is to reduce the chances of a failure occurring as much as possible by eliminating the root causes. The tool works as a summary of knowledge that allows for the creation of a history based on previous experiences with similar products/processes, making it possible to use this information for future improvements.
Using FMEA in a consistent manner ensures that failures are eliminated, resulting in increased reliability of the service provided and greater safety and customer satisfaction. Its application has a direct impact on the company’s financial returns as it minimizes, or eliminates, potential failures in production processes.
Main types of FMEA
There are several types of FMEA, but they all share the same goal and differ only in the way they classify risks and name the elements. The most common types of FMEA are:
DFMEA – Design failure mode and effect analysis
Also known as Product FMEA, DFMEA is specifically aimed at product design. It addresses the prevention of product design related issues before going into production, such as potential malfunctions, reduced service life or safety and regulatory issues.
PFMEA – Process of Failure Mode and Effects Analysis
PFMEA seeks to identify potential failures in the planning and execution phases or in changes to processes. It can involve manufacturing, assembly, transactions or services.
In PFMEA, the team focuses on failure modes and their causes that could result from the actual production or service process, and not product design.
In addition to the two types mentioned, there are also System, Service and Software FMEAs.
How to implement an FMEA
Now that you know a little more about what an FMEA is and the main types, let’s look at the first steps before implementation:
- Understand your customer’s needs
- Define the scope of the FMEA (design, process or other)
- Define the multidisciplinary work team and involve related areas
- Define the format of your FMEA form
After completing the steps above, you can proceed to the steps that will help you determine how to implement the FMEA. This involves identifying:
1. Failure mode
Sit the team down and brainstorm to determine potential failures that could occur and their effect on the process, product, service and, inevitably, the customer.
2. Potential failure effect
The effect is the consequence of the failure in question. More than one effect can usually be identified for each failure.
3. Severity (S)
Severity is the degree of the effect of the failure. A scale of 1 to 10 is generally adopted, where the effects of a failure that are considered extremely severe is 10 and 1 represents a negligible effect.
4. Cause of failure
Determine all possible causes for each failure mode.
5. Occurrence probability (O)
Occurrence probability is the likelihood of a certain effect occurring and resulting in a failure. Occurrence probability can be rated on a scale of 1 to 10, where 1 represents an extremely low probability and 10 a very high probability.
6. Process controls
These are the current controls used to prevent or detect failures, and they can be tests, procedures or mechanisms that ensure that failures do not reach the customer. These controls can prevent a failure from occurring, or reduce its likelihood. They can also detect failures after the cause has been detected, but before the customer is affected.
7. Detection (D)
Detection is an estimate of the probability of detecting a failure with the current process controls. It can be rated on a scale of 1 to 10, where 1 is extremely likely that the control will detect the failure and 10 is unlikely/impossible that the failure will be detected (for example, if there is no control).
8. Risk Priority Number (RPN)
The risk priority number is calculated by multiplying severity by occurrence by detection (S x O x D).
This number helps to classify and prioritize detected failures- that is, the order in which they should be addressed and whether immediate action is required.
An example of FMEA
Below is a detailed step-by-step example of how to perform an FMEA. Keep in mind that this is just a simple and didactic example to make it easier to understand.
- Let’s consider the process of testing a finished car at an auto factory.
- In this FMEA example, we detected two failure modes:
- The brakes don’t work
- The car won’t start
- So, we ask ourselves, “if this failure occurs, what could happen?” The effects of the failures are:
- The consumer can’t get to their destination
- As an accident is the worst possible scenario, we classify the severity as a 10, and for the second effect, which is not so serious, we classify it as a 7.
- “What could cause these failures?” We cite two probable causes for each failure mode:
- The braking system does not work or the wheels slipped in the test.
- Battery problem or no fuel.
- As this is a new car, fresh out of the factory, we can consider:
- Probability of occurrence 2 (low) for the problem being the wheels and 7 (high) for the probability of the problem being in the braking system.
- Probability of occurrence 5 (moderate) of the problem being in the wheels and 8 (high) for lack of fuel.
- As mentioned above, process controls can either prevent the failure or detect it after it has occurred. In this case, the signs we have for the problems are:
- The noises in the braking system. Brake pads emit different types of noise and each one represents a different kind of failure. These noises include high and low frequency squeals, judders, groans, moans, rattles, clacks, chirps and creaks. That is to say, ideally, a fully functioning braking system is free of any noise.
- Another control would be the tread wear indicator (TWI), which measures the thickness and depth of the tire treads.
- The car panel works as a control to detect both the battery problem and the lack of fuel.
- The lower the detection number, the greater the chance of detecting the failure. So we classify them as follows:
- Brake noise as 2 since it is extremely likely to be heard, and 3 for the tread wear indicator.
- The battery problem as 5 and the lack of fuel as 3.
- Finally, we calculate the RPN. The higher the RPN number, 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 brakes don’t work), which means that verifying this system should be the automaker’s improvement priority.
After finalizing the FMEA, what should you do with the results?
This last step is the most important one because if it’s not done correctly, none of the previous steps will benefit your product or process.
After finalizing the FMEA, we use the results to:
- mitigate high risk failures
- reduce the severity of effects and probability of occurrence
- implement controls to improve failure detection
- create action plans with schedules and identify the people responsible for implementing each improvement
- reassess to ensure the objectives have been attained
The FMEA results help to improve the reliability of the service provided and ensure greater satisfaction among customers, users and end consumers.
Now that you know about FMEA and how to implement it in your company, I invite you to get to know SoftExpert FMEA. This solution helps organizations improve productivity and reduce costs, while satisfying the requirements established by international standards and regulations, such as IATF 16949 and ISO 9000.
To learn more about the advantages and benefits that SoftExpert FMEA can offer your company, contact our experts. They understand your challenges and can recommend the best way to implement the FMEA solution to satisfy your needs.