PFMEA vs DFMEA: Core Benefits and Differences

If engineers had a crystal ball to predict every potential failure during the design or manufacturing phase, they’d be over the moon (literally, in some cases). But reality isn’t quite so magical. That’s why, in the 1960s, NASA came up with a game-changing methodology: FMEA (Failure Mode and Effects Analysis).

Why? Because when you’re building spacecraft, there’s no room for error. A single failure could mean catastrophic consequences. FMEA was their way of identifying potential problems before they happened, ensuring every system was fail-proof.

Fast forward to today, FMEA has evolved into two main areas: DFMEA (Design Failure Mode and Effects Analysis) and PFMEA (Process Failure Mode and Effects Analysis). These methods have become the backbone of industries ranging from aerospace and automotive to virtually every manufacturing sector.

Let’s do a head-to-head of DFMEA vs PFMEA to find out what they’re used for and their key differences.

What is FMEA?

FMEA, or Failure Mode and Effects Analysis, is the groundwork, the overarching methodology, upon which the concept of identifying potential failures, assessing risks and their management, and developing solutions are based. DFMEA and PFMEA are branches of it, with their application being highly specific:

Failure Modes poses a simple but necessary question, that is: “What can go wrong in this process or design?”. Let’s take two examples:

• If you’re running a sports team, one of your players could get injured due to overtraining.
• If you’re an automaker, a car’s engine could overheat.

The goal is to list out all the possible failure modes that could occur during the design, manufacturing, or operational phases.

Once all potential failure modes are listed, what happens if they do indeed occur must be considered. What’s the effect of each failure?

• An injured player would underperform and potentially decrease the morale of the team.
• An overheating engine could damage the engine to the extent that it breaks down, potentially causing the driver to be stranded.

FMEA is all about understanding the consequences of a failure. For more guidance around FMEA, find our in-depth guide here.

What is DFMEA?

Alright, let’s circle back to DFMEA, or Design Failure Mode and Effects Analysis. It’s a proactive approach taken during the designing phase of a product as a safety check, a thorough go-through of the product done to look for potential weaknesses. Any issues that could, during the later phases, cause any sort of issues. And its goal? Building the best possible product by spotting weak points and addressing them early on.

DFMEA provides the following benefits:

• Improves product design by identifying potential flaws early on
• Ensures designs meet performance and durability expectations
• Cuts down on expensive redesigns and warranty claims by catching issues upfront
• Leads to better, more reliable products that keep users happy

The process DFMEA follows is quite straightforward:

Step 1: Identify Failure Modes

This requires good ol’ sitting down and jotting down potential flaws in your product’s design. Think of all possible ways a product could break down, whether in the near or distant future of its lifecycle.

Step 2: Evaluate the Effects

What are the consequences of these failures? Consider how severe their impact is on a product’s function and safety and, as a result, customer satisfaction.

Step 3: Assess the Severity

The severity of a failure’s impact on a product is scaled using the denomination S, standing for Severity, on a scale from 1 (least severe) to 10 (most severe).

Assuming you’re building a coffee machine. In its design, a failure in the water pump would have a high severity because it would render the coffee machine useless. A failure in its heating element would be very high severity, a solid 10, as it could potentially harm the user. A failure of buttons would be medium severity as they might require the user to do some process manually but does not render the machine completely useless or harm the user (unless it is the power button).

Step 4: Identify the Cause

Time to start digging and tackling issues. Surface-level solutions don’t cut it—the underlying cause of every failure must be determined to fix it at the root level. A compromised component could have become so due to poor design, the quality of materials used, and many other reasons.

Step 5: Calculate the Occurrence

Denominated with the letter O, the likelihood of each failure mode occurring is rated from 1 (unlikely) to 10 (highly likely).

Step 6: Detection

It must be assessed how easy (1) or challenging (10) it is to detect the cause of a failure mode before the point of no return. The letter D is used to denote it.

Step 7: Risk Priority Number (RPN)

Now, we calculate the Risk Priority Number (RPN) by multiplying Severity (S), Occurrence (O), and Detection (D) for each failure mode.

Step 8: Develop an Action Plan

A plan is then developed to address all the potential failures based on their RPN. Those ranking high get the higher priority.

Let’s take an example to understand how these steps are implemented in the real world:

A new startup is coming up with a unique smartphone, trying to compete with the big brands in the industry. With DFMEA, they would look at failure modes in the case of a smartphone, such as a weak screen, bad ergonomics, or perhaps an unimpressive battery capacity.

The team would assess the severity of the issues they’re able to list out, their likelihood, and how easily they would be detected. By then addressing these issues, based upon the RPN, the risk of a product underperforming post-launch is reduced.

For an in-depth look at DFMEA, find our detailed guide here.

What is PFMEA?

If DFMEA focuses on design flaws, PFMEA is concerned with failures that can occur during the production process. It acts like a safety net for the production line, helping engineers in a manufacturing plant find weaknesses in their processes so they can fix them before anything goes wrong. This could involve anything from testing to packaging.

The benefits of PFMEA include:

• Helps catch issues before they cause defects or make the final product unusable
• Makes the whole production process run smoother by finding out where things can go wrong
• Reduces the massive cost to financial resources and public image caused by recalls
• Helps ensure the production process is safe, avoiding accidents and protecting the people who are working on the production line

The process of PFMEA involves the same steps as DFMEA, but the primary focus is on processes rather than the design of the product. Here’s an example of a car manufacturing process to understand the role of PFMEA:

Assuming your company is an automaker manufacturing SUVs for off-road enthusiasts. A step in your assembly process is attaching the doors. A potential issue that could occur is a misalignment of the door during the installation process, leading to panel gaps or doors being hard to close. These could also let air or water inside.

This ends up being both a safety concern and a cause for low customer satisfaction. Your production team, using PFMEA, spots this alignment issue via visual inspection during the assembly process, as it’s a relatively easy one to catch. The latch issue, though, could go unnoticed until later when the doors are tested.

To resolve this, your team might decide to improve the alignment jigs used during assembly and add extra quality checks to ensure the latch mechanism works perfectly before the car moves to the next stage of production.For more detailed insights, explore our comprehensive guide on PFMEA here.

DFMEA vs PFMEA: Key Differences

Both DFMEA and PFMEA are part of the same “overarching” methodology, FMEA, but their objective differs, so they focus on different parts of the product’s journey. Here’s how DFMEA vs PFMEA stand when compared against each other:

Focus

DFMEA is implemented during the designing phase, trying to find weaknesses in the design itself. Its primary goal is simply to provide the best possible design, one that is most reliable and least susceptible to stress.

PFMEA, on the other hand, focuses on the manufacturing or production process. It identifies risks related to how the product is made, assembled, or tested. PFMEA aims to prevent problems that could occur during manufacturing, such as equipment failure or human error. 

Inputs and Outputs

FMEA Type	Inputs	Outputs
DFMEA	– Product design specifications – Design requirements (for example – materials, components) – Prototypes or testing data – Engineering analysis (stress tests, simulations)	– Identified design failure modes (for example – part failure, weak materials) – Design improvements (for example – material changes, stronger parts) – Prioritized risks (based on severity, occurrence, and detectability)
PFMEA	– Process flow diagrams (mapping out each step) – Process control plans – Historical process data – Equipment specifications – Feedback from the design phase	– Identified process failure modes (for example – machine malfunctions, human error) – Process improvements (for example – improved training, better machinery) – Risk reduction actions (for example – more frequent inspections, process redesign)

Timing in the Product Lifecycle

DFMEA takes place during the design phase, before manufacturing begins, because the earlier potential failures are identified, the cheaper and easier it is to correct them.

On the other hand, PFMEA is conducted during the production phase once the design has been finalized and manufacturing has started. It focuses on preventing failures that might happen in the process of building and assembling the product. PFMEA is an ongoing analysis that can evolve with each production run.

Nature of Failure

DFMEA focuses on functional failures as well as any design flaws, including issues with performance, safety, and compliance, due to which a part is not performing its intended purpose or is breaking under the stress it should be able to endure. It is all about evaluating a product’s design and its ability to meet requirements.

PFMEA focuses on failures related to manufacturing, such as equipment breakdown, incorrect assembly, environmental factors, material quality, supplier issues, and any steps in the production process that could lead to defects. It aims to optimize the production process for the designed product.

When to Use DFMEA vs PFMEA

Once the concept of both DFMEA and PFMEA is clear, it becomes very straightforward to use which method to use when. 

Let’s imagine a scenario. You’re in charge of designing a new braking system for a car. Using DFMEA, you’d take a hard look at each component individually—in the case of brakes, it would be brake pads, calipers, and discs. You would identify any potential issues, like sub-par material quality, and fix them before the design is approved.

Now, once the design is approved, we move on to assembling the new and upgraded braking system. PFMEA would be used here to assess any issues in the process, like misaligned assembly tools or incorrect torque settings, and address them so the final product doesn’t suffer from these setbacks.

To really point the drive home, in a nutshell, follow these guidelines to know which FMEA method to use and when. Which phase is the product currently in? Design or Production?

• For the design phase, use DFMEA
• For the production phase, use PFMEA

How LLumin Can Automate Failure Mode and Effects Analysis

DFMEA and PFMEA at the end of the day, rely solely on the ability to use data effectively, and what better way of simplifying the data collection and analysis process than using a CMMS solution like LLumin? Using our software, you can massively improve asset performance with insights from PFMEA and DFMEA.

Thanks to LLumin’s AI and machine learning capabilities, it automates FMEA, making the process free of human error. All activities are tracked and presented in the form of digestible reports and custom dashboards.

You can expect the following after using LLumin’s CMMS+:

• Enjoy real-time collaboration, so all team members can work together, no matter where they are physically located.
• LLumin automatically calculates RPNs based on severity, occurrence, and detection, so you know which issues need your attention right away.
• Reusable templates mean your FMEA process stays the same across all projects, keeping things consistent.
• With accurate and complete data available to you, extracting insights and making needed operational changes becomes easier.
• LLumin has the potential to scale up as your business requirements grow. It’s built to handle it all.

Schedule a demo with us today and see how LLumin’s CMMS+ performs in the real world and benefits your company as it has done so for many others.

Conclusion

Both PFMEA and DFMEA are parts of the risk management process, each serving its role. With the help of CMMS software like LLumin, both of these processes can be improved and automated, making them more efficient, accurate, and collaborative. As a result, your company could save time and money while making more calculated decisions.
FAQs

Fequently Asked Questions

How do PFMEA and DFMEA contribute to risk management?

Both DFMEA and PFMEA are great tools for managing risk by identifying potential areas of failure early on. DFMEA does this during the design phase, before a product hits the market, and PFMEA, on the other hand, looks at the manufacturing process and identifies risks like machine malfunctions or human errors, maintaining desired levels of quality standards. Together, by catching these risks in advance, they both positively contribute to risk management, fixing issues before the product reaches the customer’s hands.

Can PFMEA and DFMEA be used together?

Absolutely. They are, in fact, part of a bigger methodology, so in theory, they are designed to work really well with each other. Doing so provides a more complete picture and helps identify and address risks in both the design and production phases.

What are common challenges when implementing PFMEA or DFMEA?

One common challenge faced when implementing PFMEA and DFMEA is a lack of experience, which leads to inaccurate or incomplete analysis. The team needs to understand what FMEA is, and time and resource constraints can further corner a team into rushing and skipping important steps. Another major setback is the availability of data—if you don’t have enough information about materials or processes, the analysis won’t be as thorough. This makes prioritizing risks difficult.

How do PFMEA and DFMEA impact cost savings?

Both PFMEA and DFMEA contribute to long-term savings. If a flawed design hits the production floor, it could lead to recalls, repairs, and decreased trust in a brand’s product. Recalls are extremely expensive, both financially and in terms of brand reputation. So, addressing design flaws early on using DFMEA prevents this. PFMEA, on the other hand, prevents, for example, machine breakdowns or assembly line errors, which reduce waste and rework. Together, they make the production line much more efficient, and fewer mistakes naturally lead to less financial expenditure on correcting issues.

How often should PFMEA and DFMEA be reviewed or updated?

These are continuous procedures that need to be reviewed regularly. DFMEA should be updated when there are any significant design changes, and PFMEA whenever there are changes in the manufacturing process, such as new equipment or materials. It’s best to develop a schedule for reviewing them, quarterly or annually, and after any major events, like an increase in customer complaints or product failures.