There are Alternatives to using MTBFJust a quick note this week to pass along a message from Michael. He’s conducted a bit of research on Mean Cumulative Function and found a few papers. And, according to Michael’s request I’m working on a short introductory tutorial for those new to MCF. [Read more…] |
Eliminating early life failures
Finding and eliminating early life failures
MTBF for electronics life entitlement measurements is a meaningless term. It says nothing about the distribution of failures or the cause of failures and is only valid for a constant failure rate, which almost never occurs in the real world. It is a term that should be eliminated along with reliability predictions of electronics systems with no moving parts. [Read more…]
NoMTBF Non-Users Group
Let’s Create a NoMTBF Non-User’s Group Today
We do it right!
Those that read this blog regularly know that I, along with many others, have some passion for the eradication of MTBF from common use. We make arguments, create examples, describe the errors and encourage using other methods. The campaign seems to be going along well. Yet MTBF is still in use – in standards, in certifications, and even taught by those that should really know better. We’re making progress, but there is much more yet to do. [Read more…]
MTBF: What is it Good For?
MTBF: What is it Good For?
Guest post by Andrew Rowland, CRE, ReliaQual Associates, LLC
I. INTRODUCTION
The mean time between failure (MTBF) is arguably the most prolific metric in the field of reliability engineering. The MTBF is used as a metric throughout a product’s life-cycle; from requirements, to validation, to operational assessment. Unfortunately, MTBF alone doesn’t tell us too much. [Read more…]
Where MTBF falls short
Where MTBF Falls Short
Guest post by Chris Peterson – see her daily blog Test To Be Your Best
I have a brand new widget and I’m very excited about the design. It has features I’ve never built in before, there is a huge market need for it, and now I have to try to prove it’s reliability before I can sell it. What do I use? [Read more…]
NoMTBF guest post Challenge
In the NoMTBF newsletter I’ve announced a contest for this site.
I’d like to invite you to write a guest post on MTBF, either good or bad, for or against, a case study or how-to-use article. Just something about MTBF.
Then, if during the week we post it the site reaches a new record for visits, I’ll send you a shiny new NoMTBF logo coffee mug. [Read more…]
Weibull vs Exponential PDFs
Comparison of Weibull vs Exponential PDFs
This is a short interactive note that let’s you play with different β values and compare the impact for a simple calculation. You may need to download and install the free Wolfram Player and plugin for your browser. You can find it at
<http://www.wolfram.com/cdf-player/
Value and MTBF
Value and MTBF
The value of any task is in the result, although a few may argue about the value in the journey itself. For reliability engineering tasks, the ability to use the output of an experiment or analysis to make decisions permits an organization to derive value from the tasks. Despite a few organizations that insist on [Read more…]
Change from MTBF
If you want to make enemies, try to change something ~Woodrow Wilson
Change
Newton had it right, objects at rest tend to remain at rest, and objects in motion tend to stay in motion. We can say that both states resist changing into the other state unless some force acts on the object. You can feel this resistance when going around a corner in a car. You body seems to want to continue straight and it is the seat, belt buckle, door frame that conspire to bring you along with the car around the corner. [Read more…]
Just muttering MTBF
Anyone that knows me understands that even muttering MTBF in a conversation or even in passing will generally set me off on a anti MTBF tirade. My better friends tend to avoid the topic altogether. And those that are curious about ‘why’ will ask me. In the process I hope to help you think about MTBF and the many issues around its use, and to make or improve friendships. [Read more…]
Seeing Success Against MTBF
Since posting the article about the internal policy by Grundfos I’ve had a range of discussions concerning your efforts to eradicate MTBF. Very encouraging!
The comment by Mark on the Linkedin NoMTBF group prompted me to write about this information. Mark posted: [Read more…]
MTBF at RAMS
No MTBF and Reliability and Maintainability Symposium
RAMS is an annual multi track technical conference, rams.org. This year in Orlando and about 400 or so attended. I was rather busy, having two tutorials, and three papers. See my site for a copy of my slides and papers. It was fun, exhilarating, and very enjoyable. [Read more…]
Grundfos MTBF Policy
A few months ago at a IEC Dependability standards meeting, I met Thomas Young Olesen of Grundfos and we talked a little about NoMTBF. He said their company has a polity to not use MTBF. YES! So I asked for permission to post some information about the policy.
One interesting part of their internal site was a MTBF Calculator. [Read more…]
Electronics Failure Prediction Methodology does not work
Posted 12-11-2012 by Kirk Gray,
Accelerated Reliability Solutions, L.L.C.
“When the number of factors coming into play in a phenomenological complex is too large, scientific method in most cases fails. One need only think of the weather, in which case the prediction even for a few days ahead is impossible.” ― Albert Einstein
“Prediction is very difficult, especially about the future.” – Niels Bohr* We have always had a quest to reduce future uncertainties and know what is going to happen to us, how long we will live, and what may impact our lives. Horoscopes, Tarot
Sample size and MTBF
Samples for Testing
Normally, we life test a sample of products in order to make sure the products will last as long as expected. We assume that the sample we select will represent the total population of products that we eventually ship. It is not a perfect system, and there is some risk involved. [Read more…]
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