Author Archives: Werner Engelmaier

Mr. Reliability

Model-Based Design Used by Industry for Long Time

As a counterpoint to Terry’s post from Wednesday, many parts of our industry have used “model-based-design” at least since the early ‘80s — it just was not called that. And it has been formalized in IPC documents for some time. The first industry document urging this approach was IPC-SM-785, published in November 1992. This was […]

Two Different Worlds in Our Industry

I had not appreciated the huge differences in our electronic packaging/interconnection technology industry—and perhaps there are many others that are in the same boat as I. I originally came from the commercial electronics world; I recently had the opportunity to do some work on space electronics. In the commercial world, the time between design and […]

Tech Question of the Week: “How do I find the right laminate material within IPC-4101?”

Tom Newton’s YouTube video with the above title is fine as far as it goes. Unfortunately, neither this video nor IPC-4101 are sufficient for selecting a proper material slash sheet out of the 55 slash sheets in the B-revision and the 66 slash sheets in the upcoming C-revision, let alone the proper base material for […]

Does IPC Task Force Have Enough Competence, Values And Morals To Succeed?

Perhaps many of you are like me, I see ‘Government’ or ‘Government Relations’  in the title and I usually don’t even skim the article. The article: “IPC Prepares Policy Recommendations to Department of Defense Printed Circuit Board Executive Agent—Emphasis on Strengthening North American PCB Industry” in the April 2009 issue of the IPC Review is […]

Gold (Au)- and Silver (Ag)-Embrittlement of Solder Joints

First, the choice of the word ‘embrittlement’ is unfortunate, because it creates a mental image that is misleading. The pictures below of the crystalline AuSn-IMC and AgSn-IMC platelets and their impact on the solder joint structure illustrate the phenomenon much better. “Au/Ag-embrittlement” is the weakening of the SJ structure by too many weak interfaces with […]

Decoupling Performance Class and Quality Assurance testing—YES, and add Reliability

‘Functional Performance’ Classes cannot be equated with ‘Reliability’ classes–they are not the same. I have tried unsuccessfully in the past to put a disclaimer into the scope of these documents, to alert the readers that only an appropriate ‘Design-for-Reliability’ would assure reliability. While good quality—and IPC-6012 and IPC-6013 assure quality, is a requirement for reliability, […]