Your Reliability Engineering Professional Development Site
Implementing a new reliability development paradigm in a company which is using traditional, standards-based testing can be a perilous journey. It is especially true with introducing HALT (Highly Accelerated Life Test) in which strength against stress, and not quantifying electronics lifetimes is the new metric. Because of this significant change in test orientation, a critical factor for success begins with educating the company’s top [Read more…]
Thanks to Kirk and the folks at TED for sharing another interesting presentation. Seth Godin: The Tribes we lead is a look at how we each can lead a movement to make real change in this world. Tribes and the organization of tribes has been around a long time, in recent years though those that controlled the mass media tried a different way to influence. [Read more…]
Kirk Gray, Accelerated Reliability Solutions, L.L.C.
Many reliability engineers have discovered HALT will quickly find the weaknesses and reliability risks in electronic and electromechanical systems from the capability of thermal cycling and vibration to create rapid mechanical fatigue in electronic assemblies. Assemblies that have latent defects such as cold solder or cracked solder joints, loose connectors or mechanical fasteners, or component package defects can be brought to a detectable, or patent, condition by which we can observe and potentially improve the robustness of an electronics system. [Read more…]
Kirk Gray, Accelerated Reliability Solutions L.L.C.
Traditional electronics reliability engineering began during the period of infancy in solid state electronic hardware. The first comprehensive guide to Failure Prediction Methodology (FPM) premiered in 1956 with the publication of the RCA release TR-1100: “Reliability Stress Analysis for Electronic Equipment” presented models for computing rates of component failures. “RADC Reliability Notebook” emerged later in 1959, followed by the publication of a military handbook know as that addressed reliability prediction known as Military Handbook for [Read more…]
Kirk Gray, Accelerated Reliability Solutions, L.L.C.
In all aspects of engineering we only make improvements and innovation in technology by building on previous knowledge. Yet in the field of reliability engineering (and in particular electronics assemblies and systems), sharing the knowledge about field failures of electronics hardware and the true root causes is extremely limited. Without the ability to share data and teach what we know about the real causes of “un-reliability” in the field, it is more easily understood why the belief in the ability able to model and predict the future of electronics life and MTBF continue to dominate the field of electronics reliability [Read more…]
When we go to an automobile race such as the Indianapolis 500, watching those cars circle the track can get fairly boring. What is secretly unspoken is that everyone observing the race is watching for a race car to find and sometimes exceed a limit, finding a discontinuity. The limit could be how fast he enters a curve before the acceleration forces exceed the tires coefficient of friction, or how close to the racetrack wall, he can be before he contacts it and spins out of control. Using the race analogy, [Read more…]
After a discussion with a client this morning, and their motor vendor’s reliability engineer asked for a reference for a sample size calculation formula I recommended, I had a short email exchange with said reliability engineer. In my note with the references, I included an aside with a link to this site. He liked the site and agreed that MTBF was often [Read more…]
Now for something completely different. Roaming the net looking for an interesting advertisement or data sheet with a ‘great’ (i.e. bad) example of the mis use of MTBF, ran across that MTBF is actually being used by at least one government for department budgeting.
This is bad. [Read more…]
The term Bayesian Reliability Analysis is popping up more and more frequently in the reliability and risk world. Most veteran reliability engineers just roll their eyes at the term. Most new reliability engineers dread the thought of having to learn something else new, just when they are getting settled in the job. Regardless, it is a really good idea for all reliability engineers to have a basic understanding of Bayesian Reliability Analysis.
This series explains Bayesian Reliability Analysis and justifies [Read more…]
Most of us have seen reliability specified using a requirement like the following:
The Zeus 5000 SUV shall have an MTBF of 144,269.5 miles with a 90% confidence.
Some readers may not have seen reliability requirements specified in any other way. What they have always seen has read something like: The widget shall have an MTBF of X with a Y% confidence. This reliability requirement structure is rather ubiquitous [Read more…]
Great note [response to comment on Drain in the Bathtub Curve on NoMTBF Linkedin Group] – yes, there is a place for parts count prediction — not to determine the mtbf, to encourage proper derating, thermal engineering, and parts reduction, etc. It’s a start and as you note only one part of the reliability program. [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…]
The Linkedin NoMTBF group is growing and while not very active does have an occasional interesting discussion. Join the discussion and maybe relate how you have raised awareness around the proper use of MTBF.
http://www.linkedin.com/groups/No-MTBF-1857182/about
| the following is a discussion on the sister Linkedin NoMTBF Group recently. It was and may continue to be a great discussion. Please take a look and comment on where you stand? Do you some form of the Arrhenius reaction rate equation in your reliability engineering work?Join the discussion here with a comment, or on the Linkedin group conversion.
Fred |
Giving a presentation last week and asked if anyone uses an 85/85 type test, and a couple indicated they did. I then asked why?
The response was – just because. We have always done it, or it’s a standard, or customers expected it. The most honest response was ‘I don’t know’.
They why is the test being done? Who is using the information for a decision? What is the [Read more…]