A Few Simple Ideas to Improve Your Reliability Program

Spending too much on reliability and not getting the results you expect? Just getting started and not sure where to focus your reliability program? Or, just looking for ways to improve your program?

There is not one way to build an effective reliability program. The variations in industries, expectations, technology, and the many constraints shape each program. Here are three suggestions you can apply to any program at any time. These are not quick-fix solutions, nor will you see immediate results, yet each will significantly improve your reliability program and help you achieve the results you and your customers expect. [Read more…]

Have you ever heard the claim that “We use MTBF, as it’s working just fine”?

They may be profitable and successful in the marketplace. Is MTBF serving them well?

Probably not.

One way help the folks claiming MTBF is alright is to illustrate using a better reliability metric may provide an improvement over using MTBF. Asking a few questions may find the inevitable chink in the MTBF armor.

1. Any early failures due to supplier or assembly error?
2. Any test design to check for how long the system will last?
3. Ever notice maintenance seems to improve or degrade system performance?
4. Did you fix the time frame for the calculation of MTBF?
5. Do you plot and track the month to month changes in MTBF?

[Read more…]

Guest Post by Martin Shaw

In today’s complex product environment, becoming more and more electronic, do the designers and manufacturers really understand what IS Reliability ??

It is NOT simply following standards to test in RD to focus only on Design Robustness as there is too much risk in prediction confidence, it only deals with the ‘intrinsic’ failure period and rarely has sufficient Test Strength to stimulate failures. [Read more…]

One of the benefits of reliability engineering is that failure happens.

Everything made, manufactured, or assembled will fail at some point. It is our desire to have items last long enough that keep working for us. Since failures happen, our work includes dealing with failures.

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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…]

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…]

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…]

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.

[Read more…]

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…]

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…]

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…]

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…]

“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.

[Read more…]

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…]

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

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