Identifying the failure modes of processes, designs, and assets is a critical part of continuous improvement for manufacturers. Completing a failure mode and effect analysis (FMEA) can help companies identify and address potential failures before they cause disruptions across the plant.
However, what about other types of analysis, like design failure mode and effect analysis (DFMEA) and process failure mode and effect analysis (PFMEA)? While they share four out of their five words, these acronyms have different meanings. Each one is important at different stages of manufacturing and product development, and both can be enhanced through the use of a computerized maintenance management system, or CMMS. Let’s discuss DFMEA vs PFMEA, what makes them unique, and when you should use each one. We’ll also explore some important differences between DFMEA vs FMEA and FMEA vs PFMEA.
What Is DFMEA vs PFMEA?
DFMEA and PFMEA are both subtypes of Failure Mode and Effects Analysis, or FMEA. However, they are used to achieve very different goals.
Design failure mode and effects analysis (DFMEA) is normally used during the design phase, while process failure mode and effects analysis (PFMEA) is used to meet performance requirements during the manufacturing process.
Before we can talk in depth about DFMEA vs PFMEA, we have to establish what an FMEA is.
What Is FMEA? Failure Mode and Effect Analysis
A failure mode and effect analysis (FMEA) is the process of identifying every possible failure that could happen with a piece of equipment. The goal of FMEA is to identify potential failures, determine the outcomes of each failure, decide how important those failures are, and put a plan in place to mitigate failures.
It’s a vital process that starts from the bottom up to pinpoint the parts that are most susceptible to failure and the facility-wide consequences of a breakdown. It uses three important factors to prioritize risk areas. Severity: How serious would the effects of the failure be? Occurrence: What is the likelihood of a failure occurring? And detection: How easy would a failure be to catch before it causes wider consequences? This structured approach provides better risk management and ensures early prevention of the worst potential failures.
Benefits of FMEA
The main benefit of FMEA is risk mitigation. By outlining the potential failure modes of a design or process, a team gets ahead of those issues before they take place. This saves money, improves quality control, and minimizes unplanned downtime. It is a proactive process that also ensures a plan is in place for when a failure inevitably occurs. It is very effective at improving operations from individual product-level designs all the way to organization-wide processes.
What Is DFMEA? Design Failure Mode and Effect Analysis
Design failure mode and effect analysis (DFMEA) focuses on how a product is designed and determines how that design might fail. The purpose of DFMEA is to detect and correct potential design failures before mass production or reaching the end user. For manufacturing, assets used in product creation or packaging may undergo a DFMEA analysis before being built or utilized. The chief difference between DFMEA and FMEA is in the scope: DFMEA is focused on the design stage, while FMEA refers to the broader analysis process of identifying failure modes.
Benefits of DFMEA
The DFMEA process allows you to assess design functionality, specifications, interactions, and potential failures in the early stages of the product lifecycle. This may assess the broader design as well as provide a more specific, component-level analysis. Taking corrective action before production can lower manufacturing costs by preventing expensive, time-consuming recalls. It also helps shorten the product development timeline.
DFMEA Example
Let’s look at an example of DFMEA in packaging.
An engineer creates an efficient method of sealing a liquid product package. But during prototype testing, after about 75 packages, the bottom fails to seal. This causes the package to leak. The spillage renders the packages unusable — and poses catastrophic consequences for assembly line equipment.
Using DFMEA, the team can assess exactly where the failure occurs, how this failure impacts operations, how likely it is to occur, and how difficult it is to detect the failure.
This allows them to prioritize the issue relative to other failures, examine the root cause, and identify the right fix — whether in packaging design, equipment performance, product performance, or somewhere else.
What Is PFMEA? Process Failure Mode and Effect Analysis
Finally, process failure mode and effect analysis (PFMEA) looks at a process from start to finish and identifies potential failures. It can be used to analyze the entire manufacturing process for a product, or a section of that process, such as product assembly or packaging. PFMEA can also be used to examine other processes that occur throughout an organization.
FMEA vs PFMEA
The difference between these two analyses (as well as DFMEA vs FMEA) is in scope. FMEA encompasses all of Failure Mode and Effects Analysis. It is the tree from which all the other types branch off. PFMEA, DFMEA, and all other kinds of failure mode analysis are all FMEA — process FMEA, design FMEA, and so on.
Benefits of PFMEA
Routine process examinations help teams identify inefficiencies and high-risk areas early and often, taking corrective action before catastrophic consequences kick in. Effective, efficient process controls yield many benefits.
The PFMEA process helps mitigate risks, reduce downtime, deliver high-quality products, amplify output, enhance employee safety, and boost customer satisfaction.
PFMEA Example
Let’s look at an example in the manufacturing sector. Imagine that an automotive plant wants to modify one step of the assembly process, shifting from human assembly to a machine.
They hope to see process improvements in efficiency and employee safety, but the team is concerned about quality, equipment reliability, and environmental factors for equipment performance.
Using PFMEA, the team reviews and ranks the risk of all the potential failures relative to other points in the process, including the likelihood of failure, the impact on production, and how difficult it may be to detect equipment failures or quality issues. They use the findings to decide how and when to implement the process shift, including modifications.
Differences Between DFMEA vs PFMEA
There are several key differences between DFMEA and PFMEA. They are used at different points in the manufacturing process, for different purposes, and often by different stakeholders altogether. This table shows how they differ in scope, frequency, and application:
| DFMEA | PFMEA | |
| When they are used | During the design or redesign processes, prior to manufacturing | Before or during the manufacturing process, and as needed on an ongoing basis |
| Why they are used | To identify product design failures that could impact product quality and end-user satisfaction | To identify process failures that could slow production, cause a shutdown, or result in errors in the end product |
| How often they are used | Only during the product development process, or when the product is being redesigned | On an as-needed basis, when there are changes in the assets used, after a major failure that needs to be better understood, or when there are process changes |
| Who completes them | The product team, consisting of design, development, and product quality experts | Manufacturing team members, including supervisors, quality control specialists, production engineers, and other stakeholders |
| What happens with the results | Design tweaks and improvements, including changes to materials and form that improve the design and function of the product | Improvements in processes to avoid failures, such as improved maintenance practices, employee training, inspections, and others. |
When To Use DFMEA vs PFMEA
DFMEA and PFMEA are both important parts of product creation, but they should be used at different times.
DFMEA is used during the design process, but some products may require several rounds. The initial DFMEA may be created during the preliminary design phase, and then another DFMEA may be completed before the final design is produced. If the product is redesigned for improvements or changes are made to the design based on consumer feedback, another DFMEA should be completed before the redesigned product enters production. It should be used as many times as necessary to ensure the finished product has as few design flaws as possible and has been optimized for both safety and performance.
Similarly, a PFMEA may be completed multiple times. A manufacturing company may complete a PFMEA before ramping up production of a product to ensure it can meet quality and volume expectations. A PFMEA might also be completed after a major failure, when equipment is replaced, or when new processes are being implemented. A PFMEA could be completed an endless number of times if needed. If the process is still in use, it can be analyzed for continuous improvement.
How DFMEA and PFMEA Work Together
Despite their different applications, combining DFMEA and PFMEA is a great way to fully optimize the manufacturing process. DFMEA allows you to mitigate risk at the product level, fixing potential design flaws and ensuring each product performs as it should. PFMEA then enhances product manufacturing, leading to fewer defects and wasted funds. The advantage of conducting them at different points in the process is that they don’t get in each other’s way — they are synergetic failure analysis tools.
Benefits of Using DFMEA and PFMEA Together
While you may need to choose between DFMEA and PFMEA at an individual point, both should be used for the best risk management results. You will end up with better products and a more efficient manufacturing line while avoiding potentially disastrous recalls and downtime.
When you use DFMEA and PFMEA together, you’ll:
Mitigate Risk
Combining these risk management techniques helps identify potential failures early and often. DFMEA helps you identify high-risk design elements at or before the prototyping stage, and PFMEA focuses on process flaws that compromise production.
When you use only one strategy, or neither, you open yourself up to downtime, product waste, and longer production cycles — all of which cost you time and money.
Save Money
DFMEA helps you avoid product waste and recalls by highlighting design flaws before production begins. And with PFMEA, you’ll approach asset management proactively and resolve process steps before they result in failures.
By highlighting issues before large-scale production, you’ll use more of what you produce, avoid expensive repairs, and maximize production time with fewer rework phases. And in turn, you save money on recalls, repairs, and downtime.
Improve Quality Control
DFMEA helps measure the success of your design within the context of product goals, customer expectations, and regulations. This creates a thoughtful final product that meets quality standards. Meanwhile, PFMEA analyzes your production process to reduce or eliminate issues that could cause defects.
From design to production, DFMEA and PFMEA help ensure product quality consistency and preserve brand reputation.
How To Complete a PFMEA
Performing even a single PFMEA is an in-depth and time-consuming process, but it does not have to be overly complicated. Here’s how to complete a PFMEA in six steps.
- Form a Cross-functional Team
The first step to properly reviewing a process will always be building a team with complete visibility into every step. It’s rare for an individual in an organization to know every single part of any process. Make sure everyone on the team has dedicated time to work on the PFMEA. - Conduct Process Mapping
Map out the entire process that will be analyzed. This should be fairly granular, making note of every step along the way and marking down any potential critical points of failure. The more detailed the process mapping, the easier the rest of the analysis will be. - Identify Potential Failure Modes
Now it’s time to address the failure part of the analysis. Go step by step and identify ways that part of the process could go awry. Be thorough — consider any potential inefficiencies or gaps in the process. - Assign Severity, Occurrence, and Detection Ratings and Calculate RPN
Once failure modes have been identified, they must be ranked for prioritization. Rate each potential failure out of 10 (with 10 being the highest) by its impact on operations, likelihood to occur, and difficulty to detect. These ratings can then be used to calculate a Risk Priority Number and identify which failure modes should be addressed first. The higher the RPN, the higher the priority of the risk. - Develop an Action Plan
Now that we have a full list of potential failures and know which ones need to be prioritized, corrective action can be planned to mitigate the highest risk ones. - Track and Review
After action is taken, continuously review the results to gauge how effective risk mitigation was as well as the PFMEA itself. Adapt and improve as needed, and take what you learn into your next failure analysis.
How To Complete a DFMEA
While the subject of a DFMEA is completely different than a PFMEA, many of the steps are similar at a broad level.
- Form a team: In this case, make sure members have a range of product design knowledge.
- Identify product failure modes and their root causes.
- Assign severity, occurrence, and detection ratings and calculate RPN.
- Take action to address design risks, usually through redesign.
- Run a follow-up DFMEA to check if RPN has been reduced and confirm if further action is needed or if the product design is ready to move forward for manufacturing.
Which Failure Mode Should You Use: DFMEA vs PFMEA
If you’re still not sure whether to use a DFMEA vs. PFMEA, ask the following questions to narrow down which is best for your use case:
- Are you trying to correct problems in the product (DFMEA) or the production of it (PFMEA)?
- What stage of the product life cycle are you in? If the product is still in the design phase, use a DFMEA. If the product is in production, use a PFMEA.
- Are the problems you want to address more related to the design (such as component failures or material weaknesses), or the process (such as product assembly or equipment malfunctions)? If the former, use a DFMEA, and if the latter, use a PFMEA.
DFMEA and PFMEA are both important processes in product development and manufacturing. Whether you’re designing a product for mass production or improving processes throughout a manufacturing plant, a computerized maintenance management system, or CMMS, can be a useful tool for tracking and improving operations.
Collect Data To Improve DFMEA and PFMEA Accuracy
No matter whether you’re performing a DFMEA, PFMEA, or a different type of FMEA entirely, gathering real data will enhance the entire process. Using a CMMS as a risk assessment tool
can help you identify trends in equipment failures and processes over time and show how process or design improvements have impacted them. Such documentation is important for continuous improvement and ensuring excellent product design and manufacturing quality based on actual insights.
A CMMS can also be key in increasing product reliability and improving RPN scores. By tracking assets and gathering performance data, your team will be well-equipped to perform thorough equipment analyses and boost performance with targeted maintenance.
To learn more about what a CMMS can do for your team, speak with a specialist or request a free demo of eMaint CMMS.
