Your Reliability Engineering Professional Development Site
Threaded connections on process chemicals and utilities piping can be difficult to seal. Leaks from threads in steam and compressed air service are common. This article looks at pipe thread design and the proper sealing of threads. [Read more…]
Guest Post by James Kline (first posted on CERM ® RISK INSIGHTS – reposted here with permission)
An organization’s culture is an important determinant of its success or failure. This is because an organization’s culture is the combined effect of the employees’ underlying assumptions, beliefs, attitudes and expectations. Each can affect performance and adaptability. A cultural assessment can help determine areas that can inhibit mission accomplishment. This article lists the different techniques used in conducting a cultural audit and indicates how it can help guide corrective action. [Read more…]
Lean product development might mean different things to different organizations, but let’s start with the 5 principles of lean manufacturing and see how it can be applied to the product development process. [Read more…]
This is part of a short series on the common life data distributions.
The Poisson distribution is a discrete distribution. This short article focuses on 4 formulas of the Poisson Distribution. It is also known as the rare event distribution. It has application in a homogeneous Poisson princess and with renewal theory. [Read more…]
Hey Ash,
I have a question about whether I should stay in my current engineering job or pursue other options.I work for an engineering firm that does contract work for other companies. We have recently lost a big contract. With this lull, I have been told that much of my work over the next several months will basically be document control.
As a new engineer, I am concerned that I will be missing out on valuable experience if I am not working on strong engineering projects.
So my question is, should I stick it out or look for another job?
Thanks,
-Anonymous
In the article Process Capability I – Overview and Indices, the main process performance indices were defined. In the article Process Capability Analysis II – Estimating Percent Defective, ways to calculate the percent defective were introduced.
In this article, the mathematical connection between the Cp index and percent defectives is made.
A key characteristic of Design of Experiments is the resolution. This is a concept that is often misunderstood, or not understood at all. We have attempted to provide a quick discussion so a user can determine if they are at risk. [Read more…]
In most organizations being a reliability engineer is a lonely position. I like to think we’re so effective that one or just a small team is all any an organization needs.
As with any engineering position, we have specialized training and skills. We view the world and problems just a little differently than others. Then we use statistics, which tends to future isolate us from our peers.
For over 50 years there have been professional societies focused on supporting the professional education of reliability engineers. For nearly as long there have been trade journals and newsletters. Longer for technical journals and other scientific and engineering organizations and journals. [Read more…]
Those who know me well know I am a voracious reader. From newspapers and magazines to business related books and novels it’s a rare site to find me without my Kindle or some type of printed reading material. Lately I have noticed a number of articles on the reasons why your best employees are leaving your business and I have to say I saw this problem trend coming more than a decade ago. [Read more…]
Many explosions in the processing, manufacturing and bulk materials handling industries involve flammable gases or vapours and explosive dusts or fibres. Such chemicals are known as hazardous materials. This article provides a basic overview of the design requirements for hazardous areas.
Guest Post by Malcolm Peart (first posted on CERM ® RISK INSIGHTS – reposted here with permission)
Most of us are aware of the old saw “the operation was successful, but the patient died!” which has been around since 1829 and used to describe medical, as well as military and business failures. There are many reasons for failure but is ‘over-management’ one of them? Can too much ‘project management’ be applied to the point that the aim of the project, i.e. the product, is compromised? [Read more…]
One of several reasons for emphasizing product requirements includes enabling modeling and simulations of designs, as well as ensuring adequate verification and validation testing.
Recall the fundamental framing of a requirement as:
Note the framing (within the requirement) of a mathematical and/or experimental relationship where “Y” is the output as a function of “(x)” as the input….Y = f(x) or as a function of multiple inputs Y = f (x1, x2, x3…xn). Let’s expand on this for a moment:
This is part of a short series on the common life data distributions.
The Pareto distribution is a univariate continuous distribution useful when modeling rare events as the survival function slowly decreases as compared to other life distributions. This short article focuses on 7 formulas of the Pareto Continuous Distribution also known as the Pareto distribution of the first kind (there are three kinds, apparently). [Read more…]
I was asked “Do you know about Singularity design?” I hadn’t heard the term in that context before.
It’s the concept of not approaching design from multiple disciplines. The design process is done with an approach and knowledge base of all needed disciplines at once and in conjunction. The electrical system isn’t designed by an electrical team and the mechanical by a mechanical team. The “Design Team” 
designs both simultaneously. Team members knowledge might be rooted in one discipline but there is clearly no boundary to their knowledge of other disciplines. This would be a mechanical engineer who has designed a PC board before.
In my prior article, Process Capability I – Overview and Indices, the process capability concept was defined for prototype samples and serial production. The data is assumed to be normally distributed and Pp, Ppk, Cp, and Cpk indices were defined. Its application to one-sided and two-sided tolerances was discussed. This article provides methods to estimate the percent defective.
The engineering tolerance for a critical characteristic is 10±0.2. So the lower specification limit (LSL) is 9.8 and the upper specification limit (USL) is 10.2. A sample of 30 parts provided measurements of the critical characteristic. The sample mean ($-\bar{x}-$) was 9.951 and the sample standard deviation (s) was 0.1825.
