Eliminating design failures when developing new products is all about finding and strengthening the weakest links.
And your first step is DFMEA.Performing a DFMEA audit at your organization helps you discover and remove potential design flaws before they cause catastrophic damage to your company.
What is DFMEA?
Design failure mode and effects analysis (DFMEA) is a tool to help companies discover and mitigate failure points in the design of their products. The idea is to identify potential failures early so they can be avoided before causing lasting damage.
The goal of performing a DFMEA is not only to find and mitigate failure points but also identify the severity and impact they would have on your organization. Performing a DFMEA analysis can help you determine if you need to recall a product or merely rework it to remove the potential for certain types of failures.
DFMEA vs. PFMEA vs. FMEA
DFMEA is part of a larger family of failure mode and effects analysis (FMEA) operations that started in the U.S. military during the 1940s. A FMEA is a methodical approach to identifying all possible failures of a design, product, process, or service and provide potential solutions to preventing those them.
While Design FMEA is a component of FMEA that focuses on product design, Process FMEA focuses on discovering and mitigating failures in a particular process. The easiest way to think of it is if you’re looking to bring a new product to market, a Design FMEA would help you discover potential problems in the design of the product while a Process FMEA would help you discover problems with the production process. One looks at what you produce, while the other looks at how you're producing it.
Essentially, the goal of the family of failure mode and effect analysis audits is to help companies discover any potential problems in the products, processes, and procedures and avoid costly failures. Performing a failure mode and effects analysis at your organization is one of the best ways to find ways to improve your products and operations.
The DFMEA Audit
There are four main areas of a DFMEA audit:
- Failure mode
- Failure effect
- Failure cause
- Severity of failure
This pertains specifically to the way the item failed to meet quality standards. Failure modes can be classified as full, partial, intermittent, or unintentional.
A full failure is when the component cannot function in any way and needs to be replaced. Partial failures are when the component can still perform some of its intended functions but is not performing as it should. Intermittent failures are when the component fails at random intervals. Lastly, unintentional failures are when the failure was affected by a different item.
Let’s look at some quick examples. With your smartphone, a full failure would be when your smartphone does not work at all. It wouldn't turn on and you couldn't use it to go online or make calls. A partial failure would be if the phone could perform most of its functions, like letting you call, text, and browse the web, but the camera doesn’t work. An intermittent failure would be if the phone functions as expected most of the time, but randomly turns off or stops working. An unintentional failure would be if you dropped it into a pool. The water affects the phone, causing it to fail.
The failure effect refers to the effect the component's failure has on the rest of your production. If a failure results in unexpected downtime of a critical asset, the impact is severe. If the failure results in a light bulb shorting out, the effect is minimal.
For example, if a light bulb goes out in the maintenance office after an electrical surge, it won’t have a large effect on your production. However, if the electrical surge results in your machine press going offline, that would severely impact production.
This is where you finally discover the “why” behind the failure. The goal at this stage is to determine the precise cause of the failure, or at least as close as you can. Sometimes you may not be able to pinpoint the exact cause right away, but you can at least narrow it considerably and after a few trials and errors, you should be able to find the root cause.
It’s important not to get too off track at this stage. While you want to identify any potential failure points you may find, the farther down the “rabbit hole” you go, the farther away from the root cause you’ll be. Keep your descriptions of the potential causes clear and concise and don’t stray too far from the most likely causes.
Severity of the failure
This is where you determine the severity of the failure on your organization. More than just the effect on production, how would this particular failure impact your organization as a whole.
Going back to the example of the smartphone, if you drop your phone in the pool and it stops working, the company must provide a new phone. It costs money and it’s frustrating, but it does not have a large impact on the organization overall. However, if the security features of your phone failed and sensitive company and customer data leaked onto the Internet, your company could face severe consequences.
The Risk Priority Number (RPN)
The next step after identifying the failure mode, effect, cause, and severity is to assign the failure a degree of risk. The Risk Priority Number (RPN) is the identifier you use to determine the level of risk the failure presents to your company.
The RPN is calculated using:
- Severity of failure effect (S) from low to high
- Frequency of occurrence (O) from infrequent to frequent
- Detectability/preventability (D) from very detectable to not detectable
Each factor is ranked from 1-10, with one being the lowest and 10 being the highest. The RPN is calculated by multiplying the three values, giving you a score anywhere between 1 (low risk) and 1,000 (high risk).
Determining the RPN for failures helps you determine which ones you need to address first.
After the DFMEA Audit
The goal of an audit is to determine your RPN, so it follows that your actions in response to the audit should be to lower the RPN. To start with, you need to determine which actions you need to take to correct the failure.
The severity of the failure is a good place to begin. For items and products with a low RPN, you can simply revisit the design with your engineers and look for any weaknesses. If your team is large enough, bring in someone from another team who did not work on that particular design to get another set of eyes on it. For designs with a high RPN, you may need to consider starting from scratch or bringing in outside experts. Keep in mind that the severity of the failure on your organization should only be revised once the failure has been completely removed.
To lower the occurrence rate, examine the causes of the failures to see where you can make improvements. One of the best ways to lower the occurrence rate is to use preventive maintenance software to schedule regular inspections. You can also use the software to automatically generate a work order to perform maintenance before failures occur.
You can also use preventive maintenance software to improve your ability to detect failures. These software solutions are all about collecting large amounts of data on your assets and your operations to help you detect problems early and work quickly to get them resolved. You can tell the software to look out for issues based on metrics from your engineers, technicians, or third-party experts.
Most importantly, you need a way to keep track of the corrective actions you take and the performance of your assets and production lines. If you don’t, the same problems are likely to occur, and you’ll need to start the process all over again. A good asset management software is the best place to track and store all your critical data.
Design failure mode and effect analysis (DFMEA) audits are designed to help companies detect failures in their products and discover ways to mitigate them to avoid catastrophic disruptions or damages to their organization.
During an audit, you’re looking for:
- Failure mode
- Failure effect
- Failure cause
- Severity of failure
Once you have these, you can calculate the Risk Priority Number (RPN) by assigning the severity of the effect (S), the frequency of occurrence (O), and the detectability of the failure (D) a value from 1-10 and multiply the three values together.
The best way to document the failures and work to prevent them from happening is to implement enterprise asset management (EAM) software at your organization.
When you’re ready to begin mitigating design failures at your company, reach out to our experts. You can schedule a personalized, one-on-one walkthrough of our ManagerPlus EAM software to see for yourself how you can improve your asset performance.
About the author
Jason is a storyteller at heart with a career spanning everything from film and TV to iPhones. Just don't expect much before his first cup of coffee.