Your Reliability Engineering Professional Development Site
A listing in reverse chronological order of articles by:
Would you like age-specific field reliability of your products and their service parts? Age-specific field reliability is useful for reliability prediction, diagnoses, forecasting, warranty reserves, spares stock levels, warranty extensions, and recalls. Nonparametric estimation of age-specific field reliability is easy, if you track parts or products by name and serial number for life data. What if there are life limits? What if there’s no life data?
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“Interdependent people combine their own efforts with the efforts of others to achieve their greatest success.” Stephen Covey
If you’ve been reading the FMEA facilitation series, by now you understand the primary facilitation skills. Studying and applying these skills will help you achieve excellent results in FMEA applications. [Read more…]
I needed multivariate fragility functions for seismic risk analysis of nuclear power plants. I didn’t have any test data, so Lawrence Livermore Lab paid “experts” for their opinions! I set up the questionnaires, asked for percentiles, salted the sample to check for bias, asked for percentiles of conditional fragility functions to estimate correlations, and fixed pairwise correlations to make legitimate multivariate correlation matrixes. Subjective percentiles provide more distribution information than parameter or distribution assumptions, RPNs, ABCD, high-medium-low, or RCM risk classifications.
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Automotive Electronic parts are qualified before usage in serial production. When product quality and reliability are poor, then assembly problems, high warranty costs, poor service, and recalls occur. The OEM’s and suppliers followed different qualification plans. Ford, GM, and Chrysler and large parts suppliers started the Automotive Electronics Council (AEC) in the 1990’s, with the mission of defining a suite of common qualification tests.
The first qualification standard was Q100, which defined stress tests for electronic components containing integrated circuits. These components are in every electronic control module, some sensors, entertainment systems, safety systems, and, in the future, autonomous driving systems.
“Creativity is an ability to respond adaptively to the needs for new approaches and new products.” Frank Barron
Creativity is an essential ingredient to achieving excellence in FMEAs. Excerpts from the book Effective FMEAs will be used throughout the article.
A version of this article was previously published in the December 2015 edition of Quality Progress magazine.
Last summer while visiting my hometown, I ran into Sam, an old friend who works in a senior technical position for a very large organization. In the course of our conversation, Sam told me about a recent discussion he had with his division’s manager about the possibility of moving up in the company. He was trying to find out if his boss would recommend him for a promotion to a particular supervisory level position that had just opened. His manager’s reply was provocative. He said, “Sam, you’re excellent at your job. I don’t know what we’d do without you. But before I could recommend you for a team leader position, you’re going to have to work on your soft skills.”
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Aside from meeting specific quality system standard requirements—such as those found in ISO 9001 or IATF 16949—well-designed quality system metrics also can serve as meaningful indicators of the strengths and weaknesses of an organization’s various processes.
As a quality manager, I often consider how precisely our quality system objectives and other metrics describe the effectiveness of our systems. One metric I started using recently—overall equipment effectiveness (OEE)—has provided our management team with a composite measurable that encompasses three major branches of our operation: maintenance, production and quality.
[Read more…]The mere formulation of a problem is far more essential than its solution, which may be merely a matter of mathematical or experimental skills. To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advances in science. – Albert Einstein
In this article, we will discuss how to use brainstorming to enhance FMEA effectiveness, and when (and when not) to use brainstorming.
The geometric distribution is a discrete distribution often encountered in reliability work, which contains some valuable properties worth understanding. Let’s take a look at some of these characteristics.
This model is useful when trying to answer the question, “How many trials are needed to get a particular result?” So, the number of trials is not set initially; we need to figure that out.
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How to allocate subsystems’ MTBF requirements with testing? Name-withheld-to-protect-the- guilty proposed “Top-Down” reduction in subsystem MTBF requirements; the more subsystems (in series) that you test, the lower the subsystem required MTBF! “The correct formula is
1/MTBF(subsystem requirement) = 1/MTBF(system requirement) –
((# of subsystems in series – # of subsystems tested)/MTBF(subsystem).”
This “Top-Down…” method is uncited and not found in Internet search.
[Read more…]
The binomial distribution is a discrete distribution useful for estimating the probability of success or failure when these are the only two possible outcomes. Thus, the prefix, “Bi”. Understanding the binomial distribution — how it’s used and under what conditions – is therefore a valuable analytical tool for reliability engineers.
[Read more…]“Honest disagreement is often a good sign of progress” – Gandhi
The Oxford English Dictionary defines “conflict” as, “an incompatibility between two or more opinions, principles, or interests.”
Conflicts are bound to arise from time to time. They can be positive and beneficial. An absence of any expressions of disagreement or conflict may indicate a problem in adequacy or quality of facilitation. Facilitators should not be afraid of conflict, but should learn the value of disagreements and how to manage them. Understanding the difference between healthy debates and dysfunctional arguments is critical to good facilitation. [Read more…]
One of the most important skill sets you could master to prepare you for business leadership is sales and negotiation. Some of you may be thinking, “Gosh, I’m not going into sales or marketing. I can skip this blog post!”
But I want to assure you, regardless of your field, sales and negotiation are part of it.
If you’re working in operations and want to expand your department, you need to sell that idea to your executive staff. If you’re a designer with a bright idea for a new line, you’re going to have to sell that idea to the people you work with … to the other managers, engineers and stakeholders in your organization.
[Read more…]The boiler is the heart of a refinery or power plant. Boiler failures cause forced shutdowns and put the health of the plant at risk.
Some boiler designs run the risk of thermal fatigue failure. During service, the internal waterside surfaces of the tubes form a thin, protective oxide layer. Yet if the strains caused by the combination of (1) thermal expansion and (2) restraint during temperature fluctuations exceed the oxide strain capacity, the oxide cracks. Each thermal cycle will repeatedly crack the oxide, expose fresh metal when then oxidizes, eventually forming a crack. Technically this mode of cracking is corrosion fatigue-driven by thermal cycling. Yet since the boiler water will always be mildly corrosive, for boiler applications this mode of cracking is simply called “thermal fatigue”.
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“The effects of chance are the most accurately calculable, and the least doubtful of all factors in the evolutionary situation.”
R. A. Fisher, ca. 1953
COVID-19 vaccination claims have changed from “prevention” to “reduced severity.” FDA approved Pfizer’s vaccine for 95% efficacy, compared with the placebo control sample. Pfizer’s placebo sample had 86% efficacy, compared with the US population case rate! Sample subjects resembled each other but not the US population!
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