The acronym MTBF is commonly known in our field as “Mean Time Between Failures”.

It is also associated with repairable systems in most textbooks.

It is also denoted as the theta parameter for an exponential distribution.

It is also referenced as a metric for reliability. Oh, and it is the inverse of the failure rate.

And, it is misunderstood and misused by many. I digress, as there is plenty already written on the Perils of MTBF.

What is MTBF? And where and how should it be used, if at all? [Read more…]

Fred talks about the NoMTBF blog and movement

Did you know I was interviewed for the Dare to Know podcast? The interview was fun, check it out here.

Note: this interview was some time ago (about 10 years back), near the start of the article series called NoMTBF. My thoughts haven’t changed very much. Plus, it seems this campaign is slowly working across our profession.

[Read more…]

Getting Enough of the Right Professional Development

Learning the basics of reliability engineering is where we all start. Mastering the range of skills and techniques is a never-ending quest.

Improving, maintaining, and expanding your reliability engineering professional skills takes many forms. There are plenty of options and sources to support your education, yet are you getting enough of the right material? [Read more…]

Extend Your FMEA Process with Mechanisms

One of the issues I’ve had with failure modes and effects analysis is the focus on failure modes.

The symptoms that the customer or end user will experience are important. If a customer detects that the product has failed, that is a failure. The FMEA process does help us to identify and focus on the important elements of a design that improve the product reliability. That is all good.

The issue is that the FMEA process doesn’t go far enough to really aid the team in focusing on what action to take when addressing a failure mode. The process does include the discussion of the causes of the failure mode. The causes are often the team members’ educated opinions on what is likely to cause the failure mode. Often the description of a cause is a failed part, faulty code, or faulty assembly.

Generally, the discussion of causes is vague.

[Read more…]

To make informed decisions, you need information.

To form conclusions, you need evidence and a touch of logic.

To discover patterns, you need data.

In each of these cases, and others, we often start with data. The data we have on hand, or can quickly gather.

We organize data into tables, summarize data into reports, display them in dashboards, and analyze the results to inform decisions. [Read more…]

Having the technical and business skills is not sufficient to be a good reliability engineer.

You must also work with other people. With your peers, across the management team, with suppliers, contractors, and customers.

The ability to work well with others is often complex and situational. Being aware of a few basic skills will allow you to learn and improve. Prette and Prette define social competence as the social skills:

that meet the different inter-personal demands in the workplace in order to achieve the goals, preserve the well-being of the staff and respect the rights of each other.

A. Del Prette e Z. A. P. Del Prette, Psicologia das relações interpessoais: vivências para o trabalho em grupo, Vozes, Petrópolis, 2001.

[Read more…]

Knowing how to estimate sample size or create a Weibull plot is not enough today.

Just having technical skills, while essential, is not sufficient.

Having a master of business administration (MBA) may be helpful, and it is not required; knowing the warranty and brand cost per failure is essential.

You also need to know which analysis to conduct and how it fits into the larger program and organization, plus how it impacts your customers. You also need to understand the business side of your work. [Read more…]

The fundamental technical skills, as I see it, have to include statistics and root cause analysis skills. This skill set is one of three broad areas introduced in the article, What Makes the Best Reliability Engineer?

I would say these are the minimum technical skills for a good reliability engineer. Able to calculate sample size requirements, understand a dataset, and correctly determine the root causes of a failure. [Read more…]

Here’s a simple illustration of how MTBF oversimplifies data, concealing essential information.

By convention, we tend to use MTBF for repairable data. That is fine.

You may also be aware of my dislike for the use of MTBF, for many different reasons. If you find yourself suggesting your organization, customer, industry or whomever to stop using MTBF, you may want to use this simple example to illustrate the ‘value’ of MTBF. [Read more…]

I was preparing to write this article and wondered how many search hits would appear for MTBF? So, opened Google and did an MTBF search. It is a common if misunderstood, acronym.

Beyond the 5,200,000 Google search results, it was the first page results that got me thinking. Keep in mind that Google often serves up a combination of what it thinks you are seeking and which sites have been useful for others.

Let’s break down what you find when you do an MTBF search. [Read more…]