Your Reliability Engineering Professional Development Site
As we continue to find and improve ways to master our environment, accomplish tasks, communicate, move, heal, etc. we continue to discover new materials, processes, and products. Emerging technologies often promise
They also may last longer.
As a minimum, they should last long as current solutions or longer or provide another compelling reason to use the new technology. [Read more…]
The WordPress.com stats helper monkeys prepared a 2012 annual report for this blog.
Here’s an excerpt:
600 people reached the top of Mt. Everest in 2012. This blog got about 11,000 views in 2012. If every person who reached the top of Mt. Everest viewed this blog, it would have taken 18 years to get that many views.
Once again those with a CRE are at or near the top of the salaries reported in this survey. See more at http://www.qualityprogress.com/salarysurvey
I never did like taking final exams in college as I viewed them as four hours I would rather spend doing something (anything) else. An exam is a check of what you know about a topic or subject. We prepared for those exams by reading, studying, practicing working problems (doing homework) and trying to understand the key concepts, trends, themes, etc. Some of my classmates thought it was about how much they could stuff into short term memory, others though sleep deprivation had something to do with preparing for an exam. [Read more…]
Just a couple of sample questions from deep in the body of knowledge this week.
Which of the following can be evaluated with dye penetrant methods? [Read more…]
Hi all,
I’m asking for feedback here. I’m thinking about building a subscription service that sends the subscriber a CRE preparation question a day (maybe adjustable by subscriber … not sure how to do this yet). [Read more…]
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. [Read more…]
Let’s work a sample size problem.
A random sample size, n, is to be taken from a large population having a standard deviation of 1″. The sample size is to be determined so that there well be a 0.05 risk probability of exceeding a 0.1″ tolerance error in using the sample mean to estimate μ. Which of the following values is nearest the required sample size?
a. 42
b. 106
c. 203
d. 384 [Read more…]
I recently received a question concerning what sample size to use when assessing call center calls. Not a lot of information in the request, so my answer was rather general. And, thought it might provide some insight to others facing sample size questions of their own. [Read more…]
note: if you know of a great online resource that isn’t on this list, please add a comments and we’ll add it to the list for all to share.
Shon Isenhour recently posted on Linkedin a question about online resources helpful for reliability engineers. I added my list and hadn’t seen any other links added. There must be more than the few I know about – what can you add to this list? [Read more…]
Ran across an interesting graphic in a new book recently. It single-handedly placed dependability in its proper context. It is an umbrella term that includes most of what we commonly think of as reliability and the other ‘ilities.’ It encompasses the various connotations of dependable and reliable that are conveyed during common use. And, the term dependability permits the overarching context for defining very clearly the various [Read more…]
Two short questions to evaluate your knowledge of failure mechanisms (root causes) and common reliability models. The answers will be posted in a comment, later.
Which of the following failure root causes is most likely NOT due to power line variation (electronic-based product)?
A. Circuit design margin exceeded
B. Power dissipation
C. In-rush current response
D. Mechanical fatigue [Read more…]
Let’s say we have two identical pumps share a load in parallel. The failure rate for a pump in this mode of operation is 0.0002 failures per hour. If one pump has to carry the full load alone, that pumps failure rate increases to 0.0009 failures per hour.
What is the reliability of the two pump system over a 168 hour week of operation? [Read more…]
A foundational element of probability and statistics is counting. How many ways could something occur? A simple example is a pass or fail criteria, thus when evaluating a product there are two possible outcomes. [Read more…]
In those situations where we sample without replacement, meaning the odds change after each sample is drawn, we can use the hypergeometric distribution for modeling. Great, sounds like statistician talk. So, let’s consider a real situation. [Read more…]