Normally, we life test a sample of products in order to make sure the products will last as long as expected. We assume that the sample we select will represent the total population of products that we eventually ship. It is not a perfect system, and there is some risk involved. Continue reading Sample size and MTBF
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 Continue reading Why success with HALT begins long before doing HALT
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. Continue reading No MTBF Tribe
Each of us have seen product life or component reliability claims on product literature or data sheets. We may even have received such claims stated as goals and been asked to support the claim with some form of an experiment. Standards bodies from ANSI, BSI, ISO, IEC, and others from around the world provide standard methods for testing products. This includes product life testing in some cases. Continue reading Question use of reliability testing standards
Kirk Gray, Accelerated Reliability Solutions, L.L.C.
It is easy to understand why the term HALT (Highly Accelerated Life Test) is so tightly couple to the equipment called “HALT chambers” systems. Many do not think they can do HALT processes without a “HALT Chamber”. Many know that Dr. Gregg Hobbs, who coined the term HALT and also HASS (Highly Accelerated Stress Screens), spent much of his life promoting the techniques and was also the founder of two “HALT/HASS” environmental chamber companies. Continue reading Why HALT is a methodology, not equipment
A few weeks ago I was working on a report summary that included a reliability value at 5 years for a product. The document was intended for use with customers, so it was reviewed by Marketing.
Not too many changes, which was nice as I do not consider myself a writer and certainly not a marketeer. They did ask for one change that prompts this note. They wanted the 96% reliable at 5 years to be replaced with the (roughly) 2,100,000 hour MTBF value instead. Continue reading Marketing and MTBF
Just a short note today about a great high level article in Wired magazine. Robert Capps did a nice summary and review of the significance of reliability engineering, product failure and what we can do about it.
And he doesn’t mention MTBF – which is appropriate.
http://www.wired.com/design/2012/10/ff-why-products-fail/all/
In light of the International Day of Failure, Oct 13th, let’s consider failure from a reliability engineer’s point of view. We work to understand and avoid product failures. When a product fails to deliver the desired performance attribute it is tossed away, returned, replaced, repaired, or tolerated. This may occur before or after the value of the product has been achieved. Continue reading International Day of Failure
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. Continue reading Why Parametric Variation Can Lead to Failures and HALT Can Help
Reliability, maintainability, availability, or the ‘ilities’ are common in our language with reference to products, services, equipment, and people. Joe is regularly available for the meeting; We can count on (depend or rely) Sara to finish the report on time; My car starts every morning without fail; and many more. What is meant with these concepts and specifically how do we manage achieving and sustaining business objectives related to these ‘ility’ concepts? The purpose of this short paper Continue reading What is Reliability
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 Continue reading Reliability Paradigm Shift From Time to Stress Metrics
Recently I received a question related to setting an Acceptable Quality Level (AQL) for a sampling of fielded electricity meters. The question was on how to select the right AQL for use with the sampling plan. I was not sure from the question if the sample would determine if the population would be replaced or not (expensive), or simply an experiement to determine how the meters are doing after 15 years of service (information only). Continue reading AQL decision
I cannot teach anybody anything, I can only make them think.
Socrates
This site is part a long string of attempts to eradicate the improper use of MTBF. This week two people have sent me references to work previously done and Chris sent me another podcast also highlighting issues with MTBF. Jim McLinn wrote about the possible transition away from constant failure rate Continue reading The MTBF Battle Continues