What Is Design Failure Mode & Effects Analysis (DFMEA)?

Whether you’re in the aerospace, manufacturing or automotive industry, there is no room for even the smallest design flaw. Not only can design flaws lead to costly delays and product failure, but left unchecked, they’re at high risk of putting the end user in harm’s way.

Design Failure Mode and Effects Analysis (otherwise known as Design FMEA or DFMEA) is a systematic approach used by design engineers and teams during a product’s design stage to identify potential failure modes (i.e., ways in which the design could fail) and to assess their impact on the overall system. Using DFMEA, teams can identify a design’s functions and possible failure modes, giving it a corresponding severity ranking that will determine how the design may affect the end user. 

With a DFMEA analysis, engineers can proactively address potential issues by identifying and mitigating risks early in the development process. This method helps with quality control to improve product reliability and performance before the production process even begins. And it can be crucial for any company launching a new product, especially cars, planes and other modes of transportation.

What’s the Difference Between FMEA & DFMEA?

DFMEA is a process that falls under the larger umbrella of Failure Modes and Effects Analysis, also known as FMEA. FMEA is the general methodology that helps quality engineers investigate asset, product and process failures (all the ways something can go wrong) and understand the potential failure mode effects they could have on a product’s overall performance. FMEA helps businesses anticipate problems, prioritize risks and implement solutions before failures occur, while DFMEA does this as well but only during the design phase of the product or process lifecycle. 

The U.S. Military created FMEAs after WWII to help reduce variation sources and potential failures in munitions production. It was a success, and NASA soon adopted FMEAs for its Apollo missions, which, once again, proved highly effective. Civil aviation, the automotive industry and other business sectors soon followed in implementing FMEAs to equal benefit.

DFMEA vs. FFMEA vs. PFMEA

DFMEA is one of three types of FMEA that also include Functional FMEA (FFMEA) and Process FMEA (PFMEA). All three focus on different stages of the product or process lifecycle. FFMEA and PFMEA function as follows:

FFMEA

Sometimes referred to as System FMEA (SFMEA), FFMEA examines the risks associated with how a system functions and how individual parts can break down. Its goal is to proactively prevent failure by determining which parts and systems are essential to an operation and scheduling preventative maintenance to keep assets running smoothly. 

PFMEA

PFMEA examines all possible failures within a particular existing process (or a portion of a company’s operations). It predicts what can go wrong during a system’s operation and allows teams to keep it fully operational during inspections and routine maintenance. 

Key Industries Using DFMEA 

There are several industries that perform DFMEA as a crucial part of their process for new product introduction and new technology integration. These industries include: 

• Automotive: Through its tools and analysis, DFMEA gives automotive companies the ability to produce higher quality vehicles, and owners can be assured that safety and performance are priorities for automakers. DFMEA also helps these companies adhere to regulatory requirements.
• Aerospace: Design flaws in aerospace can result in the loss of life. As such, DFMEA is critical in enhancing the safety and reliability of aircraft parts and systems. Aerospace engineers apply DFMEA to identify possible failure points in components, subsystems and materials, analyzing their impact on overall system performance.
• Defense: DFMEA helps defense contractors and engineers prioritize risks, enhance design robustness and improve performance in products like weaponry, aircraft, vehicles, and communications and electrical systems. It supports compliance with strict military standards and reduces the likelihood of failures that could compromise mission success, safety or operational efficiency.
• Industrial: In the industrial sector, DFMEA enhances the reliability, safety and efficiency of machinery and equipment during its design phase to identify potential failure modes in components such as motors, conveyor systems and control mechanisms.
• Manufacturing: DFMEA allows teams to analyze components and systems’ material properties, tolerances and interactions as well as to identify potential issues before they become costly to repair and/or require emergency maintenance.
• Healthcare: As with aerospace, medical errors can cause the loss of life. Healthcare systems use DFMEA with a focus on the design of patient safety and medication systems.
• Software: DFMEA improves software products and reduces costs associated with defects by using structured brainstorming to identify, rate and rank risks. 

What’s the Purpose of DFMEA?

DFMEA analyzes four critical aspects of a design failure: 

• Failure mode: This is the potential or actual failure in a component, function, element, system or process.
• Failure cause: A failure cause can stem from a flaw in design, processes, quality or part usage. When the end user is involved, human error is also a consideration for the cause of the failure.
• Failure effect: The immediate consequences of a failure on function or functionality, operations or status (i.e., how it will impact end users or customers). Some potential effects may include user injury, an inoperable product or process, product quality deterioration or specification non-adherence.
• Severity of failure: This is a quantifiable number that measures the severity of a potential failure’s effect.

As with FMEA, DFMEA assigns a 0 to 10 score to determine the failure mode’s severity, frequency and detectability. A score of 0 signifies a failure has no measurable impact, while a 10 denotes that the failure requires immediate attention. 

10 Steps to Complete the DFMEA Process

Each step in the DFMEA process is built on the last, so the following 10 steps have to be carried out sequentially for an accurate result: 

1. Define your system’s function and design requirements: Make sure all team members are knowledgeable regarding the product and its design. Identify all parts defined in the DFMEA’s scope, their functions and how they interface with each other.
2. Identify the possible failure modes: Think about potential failure modes — this is any way in which a part or product can fail (and parts may have more than one failure mode). Document them all thoroughly. 
3. Analyze the impacts of each failure mode, and give it a severity rating on the 0-10 scale: Each potential failure mode is evaluated based on how severe its effect would be if it occurred. The severity score, from 0 to 10, shows the consequences of the product’s failure on its performance, safety and end-user satisfaction. Zero represents no significant impact, while 10 shows catastrophic failure. 
4. Determine the potential causes of each failure mode: A team identifies the root causes that could lead to possible failure by analyzing a design’s weaknesses, material flaws or other external factors. 
5. Determine the failure’s expected probability ranking on the 0-10 scale: How often is a failure mode likely to occur? Much like a severity of failure score, this occurrence ranking score is rated on a 0 to 10 scale. A score of zero reflects infrequent occurrences, while 10 represents a high frequency of occurrences.  
6. Assess how easy or difficult it will be to detect this failure: Here, you evaluate the ability of your current processes to detect a design failure before it affects the end product. Once again, the detection ranking is given on a scale of 0 to 10. A score of 0 indicates it will be easy to catch (high detectability), and a 10 means it will be difficult to identify (low detectability). 
7. Calculate a risk priority number (RPN): Do this by multiplying the severity rating, the occurrence rating and the detection rating. A higher RPN indicates a greater risk and the need for immediate action.
8. Create a recommended action plan to reduce the likelihood of failure: The higher the RPN number, the more resources you should invest in that action plan. This can involve redesigns, enhanced testing or process improvements to reduce the chance of failure.
9. Record the actions you took: Make sure to document all corrective actions you took in response to these findings. Doing this shows the risks have been addressed and provides a reference to team members for future product development and issues that may arise.
10. Run another RPN calculation after changes have been made: Once you’ve taken corrective action, run a second RPN to assess the effectiveness of the changes to determine whether the risk has been sufficiently addressed or if further adjustments are needed.

How Ford Used DFMEA

Ford used the DFMEA process during the development of its 2011 Ford Explorer. The redesign of this popular SUV incorporated new technologies, including a fuel-efficient engine and an all-wheel drive system — both of which were in need of early-stage failure analysis to ensure their reliability.

Ford’s team used DFMEA to identify potential failure modes across critical parts and systems, such as the engine, transmission, drivetrain and electronic stability control. They then assessed how these failures could impact overall vehicle performance, safety and customer satisfaction. For example, they examined how a failure in the all-wheel drive system could compromise the Explorer’s handling and safety.

Next, the team prioritized risks based on the severity, frequency and detectability of potential failures. This allowed them to focus on the issues that posed the greatest threat to safety or performance. After identifying the high-priority risks, the team implemented design changes and introduced new testing protocols to mitigate these issues.

Ford’s redesigned Explorer underwent rigorous testing to address all identified risks adequately. This thorough approach not only enhanced the reliability of the new technologies but also helped Ford deliver a safer, more efficient SUV to the market.

Benefits of DFMEA 

DFMEA offers businesses many benefits, particularly in risk management and product quality. By identifying potential failure modes early on in the design process, it enables teams to proactively address risks, reducing the likelihood of problems in the final product. 

This leads to better quality and increased end-user satisfaction, as design flaws are mitigated when they reach production. Additionally, DFMEA helps decrease production costs by preventing redesigns or recalls (depending on the industry) that would otherwise arise from undetected problems.

Another key benefit is in prioritizing actions for teams. DFMEA ranks failure modes by severity, occurrence and detection, which gives teams guidance on which issues to address first, allowing the most critical risks to be resolved efficiently. Overall, DFMEA enhances design robustness, boosts operational efficiency and promotes a more reliable, cost-effective final product.