Field Engineering Blogs | PFMEA
By Gilberto Jimenez, SQA Senior Engineering Director
PFMEA is a methodology for analyzing any sort of process. Some reasons to utilize this tool include when a process is being designed or redesigned, when control plans for a new or modified process are being developed, when improvement goals are planned, and when analyzing failures. The “P” stands for “Process,” and the “FM” stands for “Failure Modes,” which are ways in which things might fail. The “EA” stands for “Effects Analysis,” which refers to studying the consequences of those failures and rating their severity. The careful selection of a cross-functional team is key to assuring that the PFMEA process is performed correctly. This team can contribute their expertise from all perspectives. This is how a business ensures that all potential failure modes are captured and accurately rated. The PFMEA process should be comprehensive. Moreover, the process also has to be effective. When it comes to FMEA, effectiveness is the name of the game.
A basic PFMEA procedure entails the following tasks:
- Assembling a cross-functional team of people with diverse knowledge about the process being evaluated
- Identifying the scope of the PFMEA
- Filling in the identifying information at the top of your PFMEA form
- Identifying the subprocesses of your general process analyzed
- Identifying all the ways in which failures could happen (failure modes) for each subprocess
- Identifying all of the consequences of the process for each failure mode
- Determining the severity rating, which is the severity of each effect
- Determining all the potential root causes/failure mechanisms for each failure mode
- Determining the occurrence rating for each cause/failure mechanism
- Identifying current process controls for each cause/failure mechanism
- Determining the detection rating for each control
- Calculating the risk priority number, or RPN
- Identifying the recommended actions
- Noting the results and the date as the recommended actions are completed
All functional team members should not only be exposed to this process, but they should also become proficient in this process. It behooves a business to instill this methodology not only in its Quality, Engineering, and Manufacturing functions but also in others such as Procurement, Contracts, and Program Management.
To perform the exercise comprehensively, perspectives from all subprocesses should be captured. The outputs of this effort are the identification of problem areas, as well as their corresponding severity ratings and the actions needed. It is also an assessment of compliance with design documents and customer requirements.
If a product was conformed and qualified many years ago, it is highly likely that the product’s current conformance is not identical to its original qualification. Engineering departments are responsible for maintaining build configurations and their associated processes from a technical design standpoint, but sometimes, sub-tier supplier process changes and manufacturing method changes are not transparent and can be sources of unexpected problems down the line.
Often, the PFMEA process can uncover process issues that were not contemplated or easily seen. The overall FMEA process resembles detective work: the “crime” (in this case, a failure mode) is identified and explained, a team is formed, each team member is asked for input, actions are determined and implemented, and, hopefully after implementation of the identified actions, the culprit is detained. SQA applied PFMEA methodology when helping one of our customers, which manufactures commercial aircrafts. Due to product variability at one of the customer’s key suppliers, which manufactured the fuselage of the aircraft, there had been a recurrence of defects across the different parts and final assemblies. The supplier did not have a robust investigation process to determine the true root cause of the issues to generate solid remediation strategies. SQA created an investigation process based on a PFMEA structure. We mapped the different processes that contributed to the failure mode (defect), determined the failure mechanisms of each process, and then analyzed the risk. High-risk failure mechanisms aligned to the first process would be considered the true root cause. In addition, we addressed and created corrective action plans for contributing root causes which were additional failure mechanisms. This process helped tremendously and saved the client millions of dollars in rework and scrap.
As this example demonstrates, utilizing this tool contributes to a business’ success. Structured continuous improvement activities are a critical function of an effective quality program. SQA Services, Inc. can help facilitate these activities within your business and identify opportunities for the use of such tools to improve the health of a supplier’s quality system.
SQA Associates can assist with the investigation processes and managing overall PFMEA and with the review of internal metrics and customer scorecards to help identify areas and products requiring attention. SQA can also coordinate and facilitate the Production Parts Approval Process (PPAP) as a whole and drive thorough PFMEA, which is the most important part of the risk assessment of your process. SQA Services is an autonomous entity that can support you with our Subject Matter Experts in the Process Field. We can assure that management teams will be on board, help the process work, and drive needed improvements. We can help identify risks and opportunities, identify possible changes, assure sub-tier supplier performance is covered, assure customer performance is accurately and completely reported, and discuss corrective actions key to business. Contact us at +1 800-333-6180 or drop us a note at firstname.lastname@example.org for more information on how SQA can support your PFMEA process.