Your Reliability Engineering Professional Development Site
With the Inside FMEA series of articles, my intention is to bring to life the subject of FMEA, and provide value to readers from all levels of experience.
Whether you are new to FMEA, or an FMEA expert, it is my sincere desire that each and every person who reads Inside FMEA articles will discover new insights about FMEA, and experience improved success in FMEA applications.
The first article, called “Welcome to Inside FMEA”, will introduce the series, and provide a glimpse of what is to come.
Readers are encouraged to contact me with any questions about FMEA, or feedback on Inside FMEA articles. Questions, feedback, and ideas for future articles can be sent to carl.carlson@effectivefmeas.com. I will personally respond to all questions and feedback.
I’m excited to bring this new series to Accendo, and hope you enjoy reading the articles, as much as I enjoy writing them. As I say to readers of my book, "best wishes for effective FMEAs."
Carl S. Carlson
Can you take into account reliability or durability functions in an FMEA? How can this be done? A reader asks this question, and it is discussed and answered in this FMEA Q and A article.
“A prudent question is one-half of wisdom.”
Francis Bacon
In this week’s FMEA problems and solutions article, the intermediate problem challenges readers to prioritize a series of RPNs (with their corresponding S, O, and D). In the advanced problem, readers are asked to weigh in on a fictitious debate between advocates of traditional RPN, and advocates of criticality assessment, using only severity and occurrence.
If you haven’t yet read the article titled “Prioritizing risk for corrective actions in an FMEA – Know before you go!“, you can access it by clicking on the link.
Note from author:
Since this article was originally published, there are subsequent articles in the “Inside FMEA” series that further describe better approaches than RPN to risk prioritization. Here are links:
Is There a Better Way Than RPN?
Risk Prioritization in FMEA – a Summary
Is There a Better Way Than RPN?
Text of the original article:
One of the most important steps in FMEA procedure is prioritizing risk for corrective actions. As soon as Severity, Occurrence, and Detection ratings have been determined for each failure mode and associated cause, the next step in an FMEA is to prioritize the risk and identify which issues need corrective actions. This step has been misapplied more often than any other step in the FMEA process.
“The perfect is the enemy of the good.”
Voltaire
What if a production worker uses a different cleaning method for an assembly operation than was outlined in the operation work instructions, and the result is customer complaints and field issues. How could this be addressed in a Process FMEA? This question is discussed and answered in this FMEA Q and A article.
“I think that probably the most important thing about our education was that it taught us to question even those things we thought we knew.”
Thabo Mbeki
Can you find this common error in detection ranking in the intermediate problem in this article? In the advanced problem, the topic of an in-service detection scale will challenge the most experienced readers.
Failure modes and their causes can be detected in service, like tire pressure monitors on your vehicle. Is that what is assessed in the Detection column of the FMEA? This article discusses detection risk, including examples, and answers this question.
Ponder this question: Let’s say you are an OEM and assemble parts made by various suppliers. When performing your Process FMEA, do you consider special characteristics for components in your Process FMEA? This question is discussed and answered in this edition of FMEA Q and A.
“The key to wisdom is this – constant and frequent questioning, for by doubting we are led to question, by questioning we arrive at the truth.”
Peter Abelard
Assessing the occurrence ranking is one of the more challenging aspects of FMEAs. This article presents problems that relate to occurrence risk assessment, based on a fictitious case study, and highlights a common mistake.
Some FMEA teams associate occurrence ranking with Failure Mode; others associate it with Effect. Still others connect associate it with Cause? Which is correct? This article discusses occurrence risk, including examples, and answers this question.
“Reality is not always probable, or likely.”
Jorge Luis Borges
As of the date of this note, the Inside FMEA series of articles has completed the “Introduction to FMEA Series,” and is nearly complete with the “FMEA Fundamentals Series.”
This year, Inside FMEA articles will continue on a monthly basis. Each article will be posted for readers on the 1st day of the month.
As soon as the “FMEA Fundamentals Series” is completed, articles will continue with the “FMEA Preparation Series,” followed by the “FMEA Facilitation Series” and the “FMEA Special Topics Series.”
Readers of my book, Effective FMEAs, will continue to find the content of the Inside FMEA articles consistent with the concepts in the book.
It is my sincere desire that each and every person who reads Inside FMEA articles will discover the articles enjoyable to read and experience improved success in FMEA applications. As I say to readers of my book, “best wishes for effective FMEAs.”
Carl S. Carlson
What if an FMEA recommended action is redundant with the Design Controls? A reader makes this observation about an earlier article, and asks the question about the value of redundancy in FMEA.
“It is not the answer that enlightens, but the question.”
Eugene Ionesco
Is action always required on high-severity issues? What if severity is high (9 or 10 on a severity scale of 1 to 10), and the occurrence and detection rankings are both low? Is action still required? This problem, as well as a challenging problem involving fail-safe strategies, are the subject of this problem-solution article.
Have you ever been in an FMEA meeting where the team did not agree on the severity rating? Understanding and correctly applying severity risk is an important part of FMEA application. This article discusses the subject of severity risk, including examples for design and process FMEAs, and offers a tip on what to do when the team does not agree on the severity risk rating.
“The only real mistake is the one from which we learn nothing.”
Henry Ford
A reader is having difficulty seeing the difference between a detection control and a recommended action, and sees them as interchangeable. This has repercussions for the linkage between the Design FMEA and Design Verification Plan, and is the subject of this FMEA Q and A article.
“The art and science of asking questions is the source of all knowledge.”
Thomas Berger [Read more…]
Consider the recommended action “Review results of XYZ test to confirm requirements are achieved.” Is this a good FMEA recommended action to address a high-risk issue? Is it sufficient? Challenge your FMEA knowledge by solving this problem and other problems presented in this article.
