A production from Empowering Pumps & Equipment as the voice of the pump and related equipment industries.
by Charli K. Matthews
[Read more…]Reliability 4.0 podcast
Exploring innovations, challenges, and experiences in maintenance and asset management.
by Sebastian Traeger
[Read more…]The Dirge of the MTBF Bias
We use our biases every day to make choices.
We select the beige sweater because we have a color bias concerning our sweaters.
Many of our biases help us quickly make decisions. We rely on biases to move through the day. Many of our biases are under the surface, unconsciously guiding our daily decisions. Mostly, biases are good or at least inconsequential.
The problem is the bias that shields us from achieving our goals. [Read more…]
Book Review: An Elementary Guide to Reliability
If you sort your Amazon search on ‘reliability engineering’ by price: low to high, you may find some interesting titles available for free or maybe a few pennies. Not one to resist a chance to fill another bookcase, it’s been a bit of a spending spree.
One of the reasons I am interested in older titles is to determine why MTBF is so prevalent today. So far, still looking and learning along the way.
There are many great books in our field. Sure, some are older. Some are not at all useful or helpful.
This book review is the first in what may become a monthly addition to the NoMTBF blog.
Today’s review is on the book, An Elementary Guide to Reliability (3rd) Third Edition
, by G. W. A. Dummer and R. C. Winton. [Read more…]
When Do Failures Count?
One technique to calculate a product’s MTBF is to count the number of failures and divide by the tally of operating time.
You already know, kind reader, that using MTBF has its own perils, yet it is done. We do not have to look very far to see someone estimating or calculating MTBF, as if it were a useful representation of reliability… alas, I digress.
Counting failures would appear to be an easy task. It apparently is not. [Read more…]
Fundamentals of Failure Analysis
Fundamentals of Failure Analysis
podcast episode with speaker Fred Schenkelberg
Failure analysis is not just about finding the root cause of a failure; it’s also about preventing future failures. Yet, the process starts much like a crime scene. Understanding some basic steps and approaches helps you fully grasp the failure and its impact or implications.
Sometimes, just identifying a failure is the difficult part. Sometimes, it’s the collection of clues or evidence. Sometimes, it’s the skills and tools needed to fully understand the root cause. The intent of any failure analysis is to understand the problem well enough to craft and implement short and long-term solutions.
Let’s explore the basics of failure analysis, the basic steps, and some ways to identify and avoid ways a failure analysis may fail. If you like, grab your Sherlock Holmes cap and magnifying glass and prepare to improve your ability to learn from every failure.
Sample Size and Duration and MTBF
Sample Size and Duration and MTBF
If you have been a reliability engineer for a week or more, or worked with a reliability engineer for a day or more, someone has asked about testing planning. The conversation may have started with “How many samples and how long will the test take?”
You have heard the sample size question.
Learn to Notice MTBF Every Day
Learn to Notice MTBF Every Day
Did you notice the speed limit signs in your neighborhood today?
If like me, you went about your commute or regular travels relatively blind. You watched for the neighbor’s dog that jumped into the road last week, yet didn’t register seeing the speed limit sign.
It’s a cognitive burden to notice the mundane or known. [Read more…]
The 3 Best Reasons to Use MTBF
This may seem an odd article for the NoMTBF site. Stay with me for a moment longer.
Over the years of speaking out on the perils of MTBF, there has been some pushback. A few defend using MTBF. Here are three of the most common (maybe not exactly the best, per se) reasons to use MTBF. [Read more…]
Teaching Reliability is Part of Your Role
Nearly everyone I’ve ever met doesn’t want or like their toaster to fail.
It will, and that is a bummer, as the quick and easy way to warm up the morning toast will be thwarted.
Failures happen. As reliability engineers, we know that failures happen. Helping others to identify potential failures, to avoid failures or to minimize failures is what we do best.
It is our ability to teach others about reliability engineering that allows us to be successful. [Read more…]
Fundamentals of Regression Analysis
Fundamentals of Regression Analysis
podcast episode with speaker Fred Schenkelberg
Most of us are familiar with the data analysis method called regression analysis. Maybe not familiar enough in some cases. The analysis allows us to identify and model trends or relationships. For example, we might examine the relationship between the speed of a production line and the number of out-of-spec items.
While regression analysis is a common method that many of us use regularly, understanding some of the limitations and options can enhance our analysis insights and accuracy. Understanding the assumptions and how to test them is a fundamental skill worth mastering.
Let’s explore a few of the limitations, checks, and options when taking a look at some data. From checking assumptions to assessing the goodness of fit, and a quick exploration of various approaches beyond simple linear regression.
A Life Data Analysis Challenge
Here is a Challenge: Life Data Analysis
Some years ago a few colleagues compared notes on results of a Weibull analysis. Interesting we all started with the same data and got different results.
After a recent article on the many ways to accomplish data analysis, Larry mentioned that all one needs is shipments and returns to perform field data analysis.
This got me thinking: What are our common methods and sets of results when we perform life data analysis? [Read more…]
10 Reasons to Avoid MTBF
“Why do you avoid MTBF?”
I got this question the other day. The person knew about the NoMTBF campaign. They didn’t quite understand why it was a big deal, especially for me, to avoid MTBF.
The tiff between MTBF and myself is not personal. The metric has not been a part of my work or caused any significant problems for me personally.
It has caused problems that have caused problems for my enjoyment of products and systems though. It has lead to poor decisions by many organizations that create items I and you use on a regular basis.
We can do better than to settle with the use of MTBF in our own work or in the work of those around us. Here are 10 reasons I recommend you avoid using MTBF.
REVIEW Analyzing Repairable System Failures Data
Recently, Ziad let me know he published an article titled Analyzing Repairable System Failures Data in the April-May 2017 issue of Uptime magazine (subscription required). He suggested I’d be interested in the article since it provides a way to analyze repairable system data without using MTBF. He was right.
The article is a short description and tutorial on using mean cumulative plotting and function (MCF). While the article recommends staying away from using MTBF, it could be a bit of a stronger message. The article does provide a very nice worked out example illustrating the use of a mean cumulative plot. [Read more…]
We’ll Meet Your Reliability But Not Your Spec
A Problem With MTBF
(Physics gets in the way!)
A Guest Post by Kevin Walker
I had an interesting case study a couple weeks ago, where “I’m giving you what you want, not what you asked for “ when the requirement as usual was a blanket MTBF, but the product design elements clearly indicated wearout could / would be a factor. — Kevin
