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What is a pFMEA? (i.e., process Failure Mode and Effect Analysis)

This article explains what a pFMEA is (i.e. Process Failure Modes and Effects Analysis) and how to use them as part of your risk management process.

RPN Scoring Table What is a pFMEA? (i.e., process Failure Mode and Effect Analysis)

I recently had someone ask for help understanding the Process Failure Mode and Effect Analysis (pFMEA) a little better. I can’t blame them, because I was lost the first time I tried to fill out a form for one. It can be confusing and overwhelming if you have never created one before.

First things first, what is a pFMEA

FMEA= Failure Modes and Effects Analysis

A lower-case letter will come before the FMEA, and that denotes the ‘what’, of what the failure is that is being analyzed. A pFMEA will often be examining process failures where a dFMEA might evaluate design failures. (dFMEA’s can be confusing as well, Robert Packard created training on how to document risk management activities without using one in his Death of the dFMEA Webinar)

Some systems capitalize all the letters. Some capitalize none. That is not what is important as long as it is consistent throughout your system. Everyone should be able to easily understand that whatever variation of pfmea is used; it means “process failure modes and effects analysis.” 

What does a pFMEA do?

A pFMEA will break down your manufacturing process into its individual steps and methodically examine them for potential risks or failures. For companies that utilize our Turn-Key Quality Management System, FRM-025 process Failure Modes, and Effects Analysis can be used as a template.

For this example, we will look at receiving inspection of injection-molded casing parts for a medical device. This receiving inspection includes a manual inspection of 10 randomly selected parts out of each delivery of 100 using an optical overlay.

Process Step

This area, as the section title suggests, is the process step. When looking at the process as a whole, the pFMEA will break it down into each and every step included in that process. This area is simply that individual step that is going to be examined.

The Process Step or item function depending on what your form uses for this scenario, is going to be part of the random sampling for manual inspection of the received parts using an optical overlay. Our example is going to be the backlighting element of the optical overlay display. The backlighting element will illuminate the inspected part against the template to verify that the part is within specific dimension criteria.

Potential Failure Modes

A failure mode is a way in which that process step might fail. Since it is failure modeS, it needs to be considered that there may be more than one way for the process step to fail. Do not be fooled that because this box on the form has been filled in that the pFMEA will be complete. A thorough examination of all of the possible failures should be investigated.

Our example in this process requires the backlighting element to illuminate a visual template over the parts. The light not illuminating properly is a potential failure mode of this process.

Potential Effects of Failure

the potential effects of the failure is a look into what the ramifications would be if that failure for that process step actually happened.

In our scenario, one of the potential effects of the lighting not functioning properly is that parts outside of the designated sizing acceptance criteria may be accepted rather than rejected as non-conforming parts.

S (Severity)

The next area is the first area that requires an estimated grading of the failure. That is ‘Severity’ which is abbreviated as S. There is a scale provided in the rating section of FRM-025 that outlines the numbering system that Medical Device Academy uses.

Below is a snippet of the rating scale used, this is included with the purchase of the SYS-010 Risk Management Procedure.

Severity (S)
Severity of the effect Scale Definition
Business Risk 0 No potential harm to patient or user
Superficial 2 Little potential for harm to patient or user

In this case, our example is using molded plastic pieces of the outside casing of a medical device. Pieces that are too large or too small will not fit when making the final assembly of the device. These plastic pieces do not happen to be patient contacting, and do not affect the function of the device.

The evaluation of this failure is determined to have no potential effect on patient safety or increase any potential for risk of harm, therefore the severity is assigned as a ‘business risk’ meaning that it bears no risk for the user or the patient. This makes the Severity Score 0.

Causes of Failure

This column is exactly that. What might cause this identified failure to happen? In our example might be the light bulbs in the overlay machine may slowly burn out over time with use. This burnout causes potential failure.

If the bulb is expected to only have a lifetime of 100 hours, then the more hours the bulb is used, the dimmer the light may become. A slowly dimming light decreases the sharpness of the overlay template and our parts that are supposed to have a + or – size criteria of 10% now have a fuzzy template that in reality changes the overlay to show closer to + or – 13%. Now parts that are too small or too large may be accepted.

O (Occurrence/Probability)

This grading criterion is also found in the Rating section of FRM-025. This is how often the failure is expected to occur. How often will the lighting element of our optical overlay fail to function in the appropriate manner for this cause?

Hopefully not very often. In fact, regularly scheduled maintenance and calibration of the overlay machine could prevent this from ever happening in the best-case scenario. Our evaluations determine that the probability of this happening is low. However, since we cannot be certain it will never happen the potential for this risk exists and makes the Occurrence score a 4.

Current Process Controls

What is currently being done to control this risk? Our example uses regularly scheduled maintenance and calibration to prevent bulb burnout affecting the overlay.

D (Detectability)

Our current process is based on routine maintenance and visual inspection. This means that the bulb burnout is something that is visually inspected for and visual inspections for detectability on the rating scale are graded as 8. This chart is found in the Rating Section of FRM-025.

RPN (Risk Priority Number)

This is a number that is found by multiplying the Severity, by the Probability, by the Detectability. In our example, the numbers RPN is  0X4X8=32 for an RPN of 32 which is considered LOW.

pFMEA math

Below is a short video explaining the math behind calculating the Risk Priority Number

https://www.youtube.com/watch?v=OWfyHyx-zhI&feature=youtu.be

Recommended Actions

What if anything can be done to improve this process? In our example, a recommended action may be to transfer from visual only inspections to verification of light output by the meter. This makes the Detectability of the failure measurable by meter or gage which is a detectability score of 4.

This changes the RPN now to 0X4X4=16

The pFMEA shouldn’t be a solo thing

If it can be avoided this type of analysis should be done by a multidisciplinary team. Sometimes in smaller companies, people end up having to wear more than one hat. There are many entrepreneurs that have to function as the CEO/CFO/Design Engineer/RA/QA manager.

Ideally, a team approach should be used if feasible. Have the management level staff who have ownership of the processes participating in this analysis. They should know the process more intimately than anyone else in the company and should have more insight into the possible failure modes of the processes as they have likely seen them first hand. They are also the type of employee who would know the types of recommended actions to control the risk of those failures as well.

The pFMEA should also be a living document

As new failure modes are discovered they should be added to your pFMEA. A new failure mode might be discovered through a CAPA because the process had an actual failure that was not originally analyzed. Take an instance like that as an opportunity for improvement and to update your pFMEA as part of a living breathing risk management system. Also, use this as a time to re-brainstorm potentially similar failure modes that may not have been considered previously so that they can be controlled before they happen.

If you took the time to watch the video above it is also mentioned that in some instances the very first FMEA must be based on estimates because there is no data. Managers and engineers may be forced to estimate the probability of occurrence. If that is the case the FMEA should be updated in the future to adjust the (O) score to reflect what is occurring in actuality based on real data and not the theoretical data that was used for the initial estimate.

Posted in: ISO 14971:2019 (Risk Management)

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Benefits of Incorporating Risk Management into Procedure Documents

By Guest Blogger, Brigid Glass
8971385878 db2fe2e49a q Benefits of Incorporating Risk Management into Procedure DocumentsThe author discusses the benefits of incorporating risk management into procedure documents. An example procedure for Record Control is included.

When I was first introduced to FMEA many years ago, I loved it. I loved the systematic approach and particularly appreciated using a Process FMEA to explain to those involved with a production process why certain controls had been put in place. I enthusiastically taught FMEA to our engineers. At the time, our bubbly, buoyant, outcomes-focused Training Manager said to me, “You Quality people have such a negative outlook. You’re always looking for what can go wrong!”  Well, yes, but it’s our role to prevent things from going wrong!  I’d found a tool to help me with that.

Next, there was EN 1441, a risk analysis standard that never satisfied, and always felt incomplete. ISO 14971 followed, covering the entire lifecycle of a product, with closed feedback loops.  So now, risks in product and process design were well covered, but ISO 13485 section 7.1 asks us to “establish documented requirements for risk management throughout product realization.”  Many of us would acknowledge that we could do better, even though we pass audits.  And what about the rest of the quality management system?  I know that when we document a procedure, we already apply risk management principles in our heads, but we usually don’t apply them systematically or write down the results.

The Idea

Recently, Rob Packard and I started work on a project that requires us to generate a full set of documentation for a QMS, compliant with both U.S. and EU requirements, including ISO 13485 and ISO 14971. We each had our ideas on how best to write a procedure, but this project provided us an opportunity to get some synergy going. Rob wanted to address risk management in each procedure. “Yes!” I said, thinking that there was a chance to fill that gap. But then it was my job to develop the template for the procedures and work out how to accomplish this…

My first results looked very complicated, so I took the KISS (Keep It Simple, Stupid) approach: one column for the hazards and consequences, and one for the risk control measures.

What I didn’t include:

  • I started with more complex hazard documentation (hazard ID, impact, trigger event, etc.). Still, I felt the benefits in the context of a procedure document was not balanced by the extra complexity and work required for analysis and training. It would be a hard sell to users within an organization who were not used to the risk management approach.
  • I decided not to assess risks and controls quantitatively for the same reasons as in the bullet point above.
  • Initially, I included references to implementation, but this would be difficult to maintain as other documents changed.
  • I thought about verification of the implementation of risk controls, then decided to leave that verification to reviewers.

Below is an example from a procedure for Record Control where records are completed on paper, then scanned as a pdf. My list won’t be the same as your list, but it is illustrative.

brigid chart 1 Benefits of Incorporating Risk Management into Procedure Documents

Standards and regulations are essentially a set of risk controls, so they are the first starting point when identifying hazards. The list should include direct risks to products, risks to the integrity of the QMS, and regulatory risks. For those of us who have been in this industry for a while, experience, past mistakes, questions fielded in external audits, and observations of other systems will yield further hazards and appropriate controls. Audits provide the opportunity to update and refine the list and test the control measures.

Benefits of Incorporating Risk Management into Procedure Documents

  • Impresses your ISO 13485 auditor!
  • When first writing procedure documents, starting the writing process by reviewing the external requirements, and systematically writing the risk section, sharpens the mind as to what must be included in the procedure. This is the same approach as in design controls, where we include risk mitigators that apply to product design in the design inputs. This is part of planning in the PDCA cycle.
  • Supports future decision-making, in the same way, that the risk file for a product is considered when a design is changed. The risk control section of a procedure provides the criteria against which any improvement or change can be assessed. Will it enhance the risk controls, or might it introduce a new hazard?
  • Serves as the basis for training on the procedure. Making visible the link between potential hazards and procedural controls much more convincing than saying, “Do this because the procedure says so,” or, “It’s in the procedure because the regs say so.”

This is part 1 in a series of blogs that leads up to our Roadmap to Iso 13485 Certification Courses

 

Posted in: ISO 14971:2019 (Risk Management)

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