… 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…]
Archives for September 2013
Reliability Math
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.
Slide set posted with permission of Chet Haibel.
Chet’s slides
Related:
Using The Exponential Distribution Reliability Function (article)
Basic Statistics (article)
The Exponential Distribution (article)
Signed up, Now What?
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…]
Third Five Questions
Third in a series exploring sample exam questions.
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…]
Reliability Program of One
All Reliability Tasks
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…]
Second Five Questions
Second in a series exploring sample exam questions.
If you have other ways to sort out these questions, please comment and let us learn and compare approaches. [Read more…]
No Feedback
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…]
First Five Questions
ASQ has posted sample exams for the past 10 or so years for the certifications. The CRE one is from 2009 and has questions used on previous exams. You can find a copy here or here.
This post has the first 5 questions with the answers explained. This is how I think or work through the problem to select an answer. Please comment if you have a different approach, especially if it would save time. [Read more…]
Reliability Goal Story
A life-support-equipment company manager desires to conduct a reliability program assessment. The company is experiencing about a 50% per year failure rate and at least the Director of Quality thought it should do better. One of the findings was related to reliability goal setting and how it was used within the organization.
Nearly everyone knew that the product had a 5,000-h Mean Time Before Failure (MTBF) reliability goal, but [Read more…]