Your Reliability Engineering Professional Development Site
A listing in reverse chronological order of articles by:
In this age of infinite information at our fingertips, it seems that fewer people are finding reference books and investing in their own libraries. After all, googling whatever’s on your mind is free and easy. But books, especially reference books and textbooks, still have a necessary place in our information age. [Read more…]
In the previous Learning From Failure article, we reviewed that chloride stress corrosion cracking (Cl-SCC) of stainless steel readily occurs at temperatures above 140°F (>60°C) when exposed to aqueous (water-based) chlorides. Although the most attention is given to corrosion from product exposure, Cl-SCC can also occur from the external surfaces as a result of corrosion under insulation (CUI). Here is an example. [Read more…]
A commonly encountered fork in the career road for many successful engineers is to a) continue engineering or b) manage others who engineer. To continue engineering is an obvious choice, and an often desired one. [Read more…]
“My software never has bugs. It just develops random features.” Anonymous
More and more mechanical and electrical systems include software integration. The FMEA methodology applies very well to software as well as hardware. It is possible to include software functionality in the System FMEA as part of the functional descriptions. However, for complex software functionality such as embedded control systems, it may be useful to perform a separate software FMEA.
Depreciation is one of the more poorly understood, yet commonly encountered terms in managerial accounting. In accounting lingo, depreciation is the systematic allocation of the cost of an asset across its useful life. That’s a mouthful. But breaking down the definition into simpler terms helps explain how its used and why it’s important when conducting Return on Investment Analysis. [Read more…]
In the previous three articles, we’ve examined the Break-even Analysis and Pay-back Period methods (Part 1 and Part 2) as means of evaluating capital investments. While these back-of-the-napkin methods are excellent starting points for analyzing investments, they’re both poor ending points. Neither provide a reliable basis for comparing investments side-by-side. And neither tell you how much value an investment is adding to your organization. [Read more…]
It is well known that chloride stress corrosion cracking (Cl-SCC) of stainless steel is caused by the combination of (1) aqueous chlorides, (2) stress and (3) temperature. Yet even with great awareness, Cl-SCC still manages to sneak up and cause many surprise failures. Here is a failure analysis case study to summarize the key factors causing this corrosion cracking mode. [Read more…]
The problems with the payback period method as a means of analyzing and comparing potential investments extend beyond its problem with the time value of money. In fact, that problem can be corrected (but rarely is in practice) by using a method called the “Discounted Payback Period”, where the future expected cash flows are “discounted” to align them with the present value of the initial investment. But even with that correction, the Payback Period Method is still lacking as a primary return on investment (ROI) analysis tool. [Read more…]
FMEAs are legal documents that support the demonstration of due care in product development. FMEA teams should ensure their worksheets are consistent with good legal practices for documents, and follow company legal guidelines.
“Common sense often makes good law.” William Orville Douglas, past Justice of the Supreme Court
If you’ve ever participated on a project team considering the purchase of a major piece of equipment, you’ve almost certainly heard of “Payback Period” – the length of time projected to recoup an initial investment through cost savings, increase profits, etc. It’s fairly simple to calculate: [Read more…]
As a teenager, my father was a house painter. He started out as a “brush and roller guy”, climbing ladders and cutting in windows. But as his business grew, he caught the attention of commercial developers with large jobs like grocery store ceilings and outfield fences. These can’t be completed with old school tools; they require a sprayer.
I remember my dad walking me through his logic of whether or not to buy a commercial sprayer. I didn’t recognize it then, but he was explaining to me “Break-Even Analysis”. [Read more…]
[This is a companion article to “Using Design FMEAs to Identify Special Product Characteristics.” These two articles should be read in sequence.]
Identification and application of special product and process characteristics help to focus assembly and manufacturing processes on the most important areas, in order to achieve the right outcomes.
“Science is the process that takes us from confusion to understanding” – Brian Greene
When a new product development effort begins, we have a clear plan to get to completion. However, part way through we start feeling it is much harder than expected. If you have ever felt that way, this video will talk about some ideas that might make it easier. It will never be simple, but it can be much less painful. Having worked to resolve the highest technical risk on a large Army program, I know it can be achieved. [Read more…]
The deeper you drill into process capability analysis, the more you realize just how many capability indices are available. The two most common capability indices are Cpk and Ppk, and the closely related Cp, Cpu and Cpl, and Pp, Ppu and Ppl, respectively. Cpm is less commonly used, and has a unique way of accounting for the centeredness of a process within its specification limits. (See my past blog posts for extended discussions about all of these.) [Read more…]
Do you ever get frustrated with long Product Development processes? Why does it happen? Is it always this way? We have produced development speed records for multiple companies. There are principles for advancing technology but also finishing in a practical time. [Read more…]
