Your Reliability Engineering Professional Development Site
All articles listed in reverse chronological order.
I’m about to leave for Nepal for a month and much of it without internet. So, this post and the next couple are homework for you. Take a look, work the problem, solve it, then show your work. Comment with why you chose your response and why you didn’t select one of the others.
This is question 17 from the ASQ CRE 2009 sample exam. [Read more…]
The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.
In Maxims for Revolutionists (1903) by George Bernard Shaw
It is those that see the world as it should be that prompts change. I believe it is those resisting change to be unreasonable; I suppose it depends on your point of view. The idea or invention may be an inspiration or take diligent work, yet the real work is in changing the reasonable to a new way of viewing the world.
During a normal day, we unconsciously tie our shoes, brush our teeth and drive to work, mostly by routine and without too much conscious thinking about the tasks. Occasionally we answer the phone and have to think a little about the conversation. Or we design an experiment for the next project, thinking we can save time by using the same test as last time. Then we slip comfortably into a routine. Do we not think anymore?
Reliability engineering is thinking.
I’m about to leave on a long trip and much of it without internet. So, this post and the next couple are homework for you. Take a look, work the problem, solve it, then show your work. Comment with why you chose your response and why you didn’t select one of the others.
This is question 16 from the ASQ CRE 2009 sample exam. [Read more…]
I recently saw a quote with the notion to stop complaining and do something positive. Which happens to work with my mother’s admonishment
If you have nothing good to say, say nothing.
So, while I’ve been railing against MTBF and then suggesting a better metric, my message on use something else has gotten lost. Recently on a Linkedin group discussion someone suggests yesbx.com as a sister site to nomtbf.com.
Maybe it is time to focus on a positive message around a replacement metric to MTBF. You already know my position on MTBF. So what do I recommend. [Read more…]
Best Wishes for all those taking the CRE Exam Oct 4th.
… Or, reliable learning. One of the best things about reliability engineering is the never ending opportunity to learn. We work with materials, assembly processes, and people creating and maintaining products, machines, and systems. Other engineering disciplines tend to focus on one aspect of a design or process – mechanical engineers make allowances for the circuit board location and heat transfer requirements, yet do not word on the circuits themselves. Electrical engineers just the opposite, they focus on electronics and power and attempt to fit within the constants imposed by industrial designers. Maybe architects are close to the breadth of reliability engineering as they contribute the aesthetic and functional elements of a design, and consider the maintenance and longevity of the building. Yet, they are not involved with the actual aging and maintenance. [Read more…]
Recently a question came to me about the difference between hazard rate and failure rate. A lot of literature and reference use these two terms interchangeably. I have long thought there is a difference, and to check my understanding I asked a good friend and reliability engineering consultant Chet Haibel. He provides a slide set (below) that described the various functions we use working reliability statistics and he details out the functions when using the exponential distribution.
Please review the slides and comment or ask questions – both Chet and I will attempt to help clarify any misunderstandings. I do think the slides are excellent and will do a great job providing a review of basic reliability math and the exponential distribution.
Related:
Using The Exponential Distribution Reliability Function (article)
Basic Statistics (article)
The Exponential Distribution (article)
Playing with Prezi and thought it would be fun to create one for the NoMTBF campaign.
Take a look, let me know what you think? And, feel free to use it as needed.
I received a note today from someone that has signed up for the Oct 5th CRE exam (about two weeks from today) and has not spent any time preparing. The request:
How should I prepare for the exam?
Reminds me of a quote about tree planting. The best time to plant a tree is 20 years ago, the second best time is now. [Read more…]
Test yourself with the third five questions from an ASQ sample exam. If you have other ways to sort out these questions, please comment and let us learn and compare approaches. [Read more…]
Having been invited to evaluate reliability practices within a company, I conducted a series of interviews with various staff members. When asked any question on the reliability techniques used, members of the engineering, procurement, operations, and quality departments all responded with nearly the same comment: “Oh, the reliability guy does that.” It appeared that the organization had one reliability engineer who did everything related to reliability. His interview was scheduled last that day. I was looking forward to meeting him. [Read more…]
If you have other ways to sort out these questions, please comment and let us learn and compare approaches. [Read more…]
Endless debate on merits of MTBF is meaningless as more than one has told me. My neighbor has a bumper sticker that says Endless War with the ‘less’ crossed out and written above it ‘this’. Instead of endless debate, how about we just end this now. Stop using MTBF and all related grand averages. Use the statistics, distributions and knowledge you have to provide accurate estimates and summaries.
Imagine you are requested to assist a design team in determining how to best improve the reliability of a product. You learn that the organization produces a range of point of sale (POS) devices and they have invited you to a meeting with their staff to discuss the product and ways to improve the field reliability.
To help understand the situation, you may have already started to think of a set of questions whose answers would lead to suitable recommendations: [Read more…]