Your Reliability Engineering Professional Development Site
All articles listed in reverse chronological order.
First off I want to say thanks to you the readers of the NoMTBF blog. The notes of thanks, of encouragement, and support all propel me to write to you each week.
I especially like the stories of success helping someone ‘get it’ concerning the common misunderstandings of MTBF. I have to think your work and actions is making a difference across the field of reliability engineering. We’re making progress. [Read more…]
The reliability engineer may have many roles within an organization.
You may be specialized and focused only on the analysis of field data. Or you may be a member of the organization’s strategic leadership team.
You might support one or more product development teams, or work with a team of reliability professionals supporting just one subsystem. [Read more…]
Monte Carlo relies on data that describes the variation of elements within the system. It also connects the elements such that they result is an estimate of performance.
For reliability modeling, this is easiest to imagine for a series system.
For a system with two elements in series, a very simple reliability block diagram multiples the expected reliability for each block to determine the system reliability value. Yet, it is possible to have both elements at the low end of the range of possible reliability values, or the high end or a mix.
That is the value of the Monte Carlo approach. [Read more…]
Most reliability engineers are familiar with the life cycle bathtub curve, the shape of the hazard rate or risks of failure of a electronic product over time. A typical electronic’s life cycle bathtub curve is shown in figure 1. [Read more…]
Predicting Failure vs. Reacting to FailureOne of the twitter notes I sent out a few weeks ago in part read, “Celebrate failures”. And a comment came back that it was a wonderful approach that she had not though of before. Failure will occur and when it does it is our chance to learn.
And, we need to learn. As reliability professionals, we continue to learn our entire career. New materials fail in novel manners. New assemblies fail in an assortment of ways. New designs fail due to unknown sources of variation. We will see failures. So rather than simply focus on the next try and hope to find success, let’s learn from each failure as we move toward success. [Read more…]
Ethics relate to the moral correctness of a person’s behavior given the groups moral principles.
Society, in general, has a set of standard expectations to guide our behavior. This includes fundamentals such as not harming others or behaving in a deceitful manner.
Religious, professional and informal ‘codes’ document the set or principles which guide our behavior in line with moral correctness. [Read more…]
Fault Tree Analysis (FTA) is a technique to explore the many potential or actual causes of product or system failure.
Best applied when there are many possible ways something may fail. For example, when my car doesn’t start, it could be a dead battery, faulty started, loose wire, no fuel, and on and on. [Read more…]
Reliability Testing with ConstraintsIn some cases we have to conduct testing and are asked to not break the product. Now, that isn’t all that fun as a reliability engineer. We want to find what fails and understand it. Or, we want to confirm what we expect will fail, actually does as expected.
So, what do we do when confronted with a very small sample size (that is one issue) and are expected to conduct failure free testing (second issue)? Let’s explore each issue separately and come up with a few suggestions on how to proceed.
Thanks to Олег (@OlegV_Ivanov) via Twitter for the article suggestion. Thanks for the idea Олеr. [Read more…]
Each organization creates their own version of a product life cycle.
Often there are phase gate reviews that signal a transition from one phase to the next. In general, each set of phases follows a common progression from idea to retirement.
There are many references that include a description of the life cycle phases, so let’s explore two of them. [Read more…]
Customers experience product failures.
Understanding these failures that occur in the hands of customers is an essential undertaking. We need this information to identify increasing failure rates, component batch or assembly errors, or design mistakes. [Read more…]
Historically Reliability Engineering of Electronics has been dominated by the belief that 1) The life or percentage of complex hardware failures that occurs over time can be estimated, predicted, or modeled and 2) Reliability of electronic systems can be calculated or estimated through statistical and probabilistic methods to improve hardware reliability. The amazing thing about this is that during the many decades that reliabilityengineers have been taught this and believe that this is true, there is little if any empirical field data from the vast majority of verified failures that shows any correlation with calculated predictions of failure rates.
[Read more…]
The Impact of IoT on Reliability EngineeringArticle inspired by @JillNewberg thanks for the suggestion Jill.
There are two elements to this subject. First there is the reliability of the elements collecting and connecting to the internet. Second is the potential value of the connection and information. [Read more…]
The planning of environmental or reliability testing becomes a question of sample size at some point.
It’s probably the most common question I hear as a reliability engineer – how many samples do we need. [Read more…]
Estimating the set of stress and stress curves is an interesting exercise that may have a greater purpose: safety.
The connection is clear when considering the potential consequences of failure.
For example, the loss of braking power when landing an aircraft may result in the aircraft rolling off the end of the runway. This could be into a river or road and may have a rather poor outcome not only for the aircraft. [Read more…]
As reliability engineers we are the local expert. We know the arcane arts of product life and equipment uptime design and maintenance. We are sought after to estimate useful life, time to first failure, and consulted when failures occur. [Read more…]