Your Reliability Engineering Professional Development Site
Find all articles across all article series listed in reverse chronological order.
Centrifugal Pump Life Extension – The Volute
What readers will learn from this article.
Guest Post by Greg Caroll (first posted on CERM ® RISK INSIGHTS – reposted here with permission)
There is a gaggle of Management Consultants pushing the 20th century mantra of Good Management Practice as a panacea to all the ill of today’s business environment. The key plank in most of these methodologies is that old chestnut “the PDCA cycle” for Continuous Improvement. If your consultant wears this as a badge, run a mile
Business Management is no longer just about Financial Accounting or Office Administration. And Best Practice is not just someone’s vague opinion. Leading businesses from around the world have, thru the international standards organization, put down a comprehensive set of guidelines for a broad range of Systems Management areas covering the lifecycle management Best Practices. [Read more…]
The McNemar test is a nonparametric statistical test to compare dichotomous (unique) results of paired data.
If you are comparing survey results (favorable/unfavorable) for a group of potential customers given two ad campaigns, or evaluating the performance of two vendors in a set of prototype units, or determining if a maintenance procedure is effective for a set of equipment, this test permits the detection of changes.
The McNemar test is similar to the χ2 test. The McNemar only works with a two by two table, where the χ2 test works with larger tables. The χ2 test is checking for independence, while the McNemar test is looking for consistency in results.
Let’s examine an example where a group of people are surveyed about a prototype design, before and after a presentation. [Read more…]
Think this was written about the elusive Sasquatch? Loch Ness monster, maybe? What about the abominable snowman?
Nope, nope, and nope. This was referring to good engineering managers.
In his opinion piece, Juan Pablo Dellarroquelle argues that engineers that are good at their jobs have little incentive to move into a managerial role because they are already influential leaders in an individual contributor role.
Alternatively, he argues, engineers who are weak technically are promoted to managers because of their organizational skills.
While this may be the case in some circumstances, in general – I disagree. [Read more…]
In my previous article we established the lean product development goal statement as:
We then derived high-level objectives as follows:
This post provides a list of my process capability articles, a short description and a link. The goal is to make it easy for the reader to locate any of the articles. It is recommended to read these articles in the order presented. This post will be updated when additional posts are written on the Process Capability topic.
This post provides a list of my telematics analytics articles, a short description and a link. The goal is to make it easy for the reader to locate any of the articles. It is recommended to read these articles in the order presented. This post will be updated when additional posts are written on this topic.
I’m facilitating an RCM Analysis this week in a second-floor conference room that overlooks a company courtyard complete with manicured landscaping, picnic tables, park benches and walking path complete with distance markers. While this park like setting has been mostly empty the first few days this week today there is a group of 30 people milling around. Some small groups of 2 or 3 are clustered together talking and most everyone is checking out their smart phone for various unknown reasons. I can’t help but wonder what is going on so I ask the team I’m working with why so many people are in the courtyard. [Read more…]
With today’s software and problem solving methodologies, there is no reason to be teaching or using Taguchi methods. They have a range of limitations and assumptions, and better options exist and are easy to use. Watch this video to learn more! Avoid falling for the sales pitch for yesterdays tools. No reason to limit your options and your learning. [Read more…]
Leading reliability efforts is a hard road. The resource required to improve reliability is significant. The resource to demonstrate reliability is gargantuan.
Guest Post by Geary Sikich (first posted on CERM ® RISK INSIGHTS – reposted here with permission)
Good intentions do not make for the creation of a robust/resilient organization. Business Continuity plans, Disaster Recovery plans, Emergency Response plans, etc., that are standalone documents generally reflect good intentions – whether to meet regulatory requirements or to address governance. I would have to say that this should be a wake-up call for executives in all industries. We live in a complex and interdependent world. Complex systems are full of interdependencies that are hard to detect. The result is nonlinearity in responses to events, especially random events/shocks.
The odds of rare events are simply not computable. Model error swells when it comes to small probabilities. The rarer the event; the less tractable, and the less we know about how frequent its occurrence. [Read more…]
What readers will learn from this article.
This article introduces readers to heat transfer in heat exchangers. It explains the concepts of temperature gradients across walls and parallel- current and counter-current flows. Both shell-and-tube and plate heat exchanges are discussed along with their common operational problems and remedies.
Shell-and-tube and plate heat exchangers (HXCH’s) are recuperative type devices, meaning that flowing fluids exchange heat through a dividing wall. The exchange of heat occurs from the hotter liquid to the cooler one. The hotter liquid is at a higher energy level than the colder liquid and the energy flows from hot to cold in an attempt to reach a steady equilibrium state at an intermediate temperature. [Read more…]
Ponder this question: Let’s say you are an OEM and assemble parts made by various suppliers. When performing your Process FMEA, do you consider special characteristics for components in your Process FMEA? This question is discussed and answered in this edition of FMEA Q and A.
“The key to wisdom is this – constant and frequent questioning, for by doubting we are led to question, by questioning we arrive at the truth.”
Peter Abelard
Mercedes used to be known for their outstanding reliability. They were the benchmark for 80 years ,no exageration. The new CLA250 model which is their base model has a reliability that is 140% less than the average rated car. What??? [Read more…]
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.
Next, a way to estimate estimate the percent defective was discussed in Process Capability III – Cp vs Percent Defective. The data showed the process had a Cp ~0.46, so even if centered, a high percentage of parts would be non-conforming! In industry, it is common to see a Cp of about 1. The paradigm is that if the process range is just contained within the tolerance range, it is satisfactory. Such processes are marginally capable. A process mean shift away from the target or an increase in variation significantly increases the number of non-conforming parts. Process Capability needs to be increased. At a minimum, Cp should be greater than 1.33, but larger is better.
There are two approaches to improving process capability. One is to center the process and the other is to reduce variation. Both need to be accomplished.
