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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
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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.
Consider these questions: How many recommendations are needed to address the root cause of a high-risk problem? If the FMEA team is addressing an issue with high-severity and high-occurrence ratings, is it usual to have a single recommended action to reduce risk? Why not? Read on, to learn the essential elements of FMEA recommended actions, and answers to this questions.
“I have been impressed with the urgency of doing. Knowing is not enough; we must apply. Being willing is not enough; we must do.”
Leonardo da Vinci
One of the more important topics in the FMEA body of knowledge is how to audit the effectiveness of FMEAs. Performing FMEAs properly and to a high quality standard is essential to obtaining the best possible results. This FMEA Q and A goes to the heart of FMEA effectiveness audits.
“Without a good question, a good answer has no place to go.”
Clayton Christensen
In this article, we use problems and solutions to learn about FMEA controls. In the intermediate problem, we continue examining the door latch-pin failure of the DC-10 cargo door, as an example to identify FMEA controls. In the advanced problem, we analyze a fictitious FMEA relating to potential safety of someone trying to unjam a snowblower.
A common error in FMEA procedure is to make entries in the Controls column that the FMEA team believes need to be done, but are not currently planned or in place. Why is this error so prevalent? Maybe the question should be why do we limit entries into the prevention or detection control column to actions or methods that are currently planned or in place?
“Never mind your mistakes. One day they will become your most prized possessions.”
Abhijit Naskar
Is it a good idea to do one generic FMEA for wiring harnesses, and use it as a reference for other FMEAs for similar applications? What about interfaces? These questions are discussed and answered in this FMEA Q and A article.
“We live in the world our questions create.”
David Cooperrider
The DC-10 case study continues by asking for causes to the door latch-pin failure. The advanced problem poses a realistic and especially challenging circumstance that FMEA teams can experience.
“Judge a man by his questions, not his answers.” Voltaire
Does a cause description need to be a design or manufacturing deficiency? Why? This is one of the more important questions to consider if you want to achieve quality FMEAs.
“The effort to get at the truth has to precede all other efforts.”
Albert Einstein
In this Q and A article, a reader asks a challenging question about the linkage between FMEA boundary diagrams and Design FMEAs. There are many linkages between different elements of FMEAs, and this question/answer highlights one of the key linkages.
“In all affairs, it’s a healthy thing to hang a question mark on the thing you have long taken for granted.”
Bertrand Russell