A Failure Modes and Effects Analysis (FMEA) is a risk management tool that identifies potential failures within a system or process and classifies them by likelihood of occurrence and potential severity. Six Sigma teams use FMEA because it accurately predicts challenges and puts organizations in a proactive rather than reactive stance.
The successful employment of FMEA requires using data and insights gained from past experiences with similar products and systems. The object is to identify failure modes and failures effects. A failure mode is defined as potential or actual defects or errors in a system. A failure effect describes how a failure mode will impact customers or end users.
There are four steps in FMEA:
- Identify potential failures and defects
- Determine potential severity and consequences of each
- Predict likelihood of occurrence
- Create systems for failure detection
A study from Total Quality Management called FMEA a “risk assessment process” that is “an essential tool for improving both product and process design.”
How to Conduct a Failure Mode and Effects Analysis
As with all projects, the first step of a successful project is assembling the right people to overcome challenges. For FMEA, that consists of a cross-functional team with members who bring a variety of perspectives as well as expertise in the process, system, product or service in question. It’s also important to have people on the team with in-depth knowledge about customer needs.
Teams then define the scope of the process that is the focus of the project. They also establish boundaries for the project, as well as determine how far into detail they will go. A whitepaper from Siemens outlines what happens next in the steps involved with FMEA.
Identify Potential Failures and Defects
Teams determine this by analyzing each functional requirement for the process and identifying, based on similar processes and experiences from the past, where failure moods are likely to occur. It’s also important to remember that one failure mode can have a domino effect, leading to failures in other components. The team also notes the failure effects of each failure mode.
This includes the consequences of failure within the process or related process, as well as to products, services and customers.
Determine Severity
In this step, teams expand on the failure effects, determining the severity of consequences from a failure mode. Teams typically develop a scoring system in this step. Siemens suggests the following.
1: No effect
2: Very minor effect, noticed only by discriminating or very observant users
3: Minor effect, with only a small part of the system impacted
4-6: Moderate effect, with most users “inconvenienced and/or annoyed”
7-8: High effect, which involves loss of the system’s primary function, leaving users dissatisfied
9-10: Very high effect, meaning the process, system or product has become hazardous, leading to angry customers and safety hazards
Likelihood of Occurrence
Teams then rank each failure mode by the likelihood of occurrence. Again, most teams find it effective to create a system that assigns numeric value to the potential of each failure, with those ranked with a “1” as the least likely to occur and those ranked with a “10” as the most likely to occur. This step often includes conducting a root cause analysis to determine the exact causes and how likely they are to occur.
Create Systems for Failure Detection
At this point, it is easy to see with just a quick review the failure modes most likely to occur and the severity of each. Teams then can create or improve current process controls to detect potential failures before they happen. These include inspections, tests, and other mechanisms used to evaluate the system or process – from a team of people doing periodic checks of a system to automated processes that look for derivation from acceptable ranges.
The job of controls is to prevent a failure mode from happening or, at the very least, detecting a failure after it has happened but before it can affect the customer or end user. It’s also helpful for teams to rank the potential controls with a rating that estimates how well it is expected to work in detecting failures.
Putting It All Together
A way to make the effectiveness of FMEA understood is using an example from day-to-day life. The process in question is a commute to work, with the goal of arriving consistently on time at the office. The team involved is everyone in the household. The first step is identifying the potential failure modes of a commute. Some of the most popular include:
- Leaving the house late
- Traffic congestion
- Failure to find keys
- Bad weather
- Getting the kids to school before commute
And so forth. The first job is to rate the severity of each. Most people can find their keys in short order (if this is a problem, a Cause/Effect Diagram might help). However, getting the kids to school is a complex process, and a failure to pack a lunch the night before or serve breakfast on time can cause major delays.
It’s then time to look at the likelihood of occurrence, based on experience. For many people, it’s congestion on the same road every day or hitting the snooze button too many times. Whatever the case, an honest appraisal of past experience leads to more accurate predictions on what aspect of the morning routine will cause an issue.
Knowing these issues, solutions can go into place. Putting the keys into the same location before bed each night. Finding alternative commuting routes. Checking traffic before leaving the house. Dividing up the duties for making breakfast and packing lunch with the kids.
Process controls can then go into place. In this case, that’s mostly visual inspections.
While obviously simplistic, this example contains the same approach that a team should use with work-related processes. FMEA can apply to everything from getting expense reports filed accurately and paid promptly to reducing the risk of errors when operating heavy machinery on the factory floor.
Because it requires an in-depth examination of a process, often before it even starts operations, FMEA has emerged over the years as one of the most popular and critical tools in the Six Sigma toolbox.
Interested in learning more about FMEA?
Eli Lilly CFO Says Process Mode Failure Analysis Important for Business Strategy
