Re: Failure Analysis

Is it really so new?

And Europe is learning fast. (Business example: The Frankfurt stock exchange requires quarterly reports instead of annual ones)

For me, it's nice: The more damage is created by idiots, the more investigations are to be carried out by my lab.

Michael Dahms

BTW: Please quote only the really necessary.

I'm in.

tom

Tom Walz Carbide Processors, Inc. Ph (253) 476 1338 Fax (253) 476 1321 snipped-for-privacy@email.msn.com

You are very accurate on your first statement. I am careful to communicate with information already known to the public (as buried as it may be). I can repackage it to make more sense and redirect the focus to the real issues which happen not to be what the media understands it to be. (because this group has a chance to understand the ramifications) The media understands politics and administrative issues but does a sorry job with materials related issues. The CAIB will say spend more money and clean up a little. The bad-old foam ramp will be eliminated and new leading edge panels will be fabricated and installed. These things could have been done (should have been) years ago. No new technology was needed. Ceramists make flower pots and toilets, right? The media don't understand that the TPS on the Shuttle is the ceramists' state of the art 30 years ago and we aren't much further along from that today (unless cost is no object and mass production will not reduce costs like making millions of Pentium chips can). One leading edge panel is $1M and only one place in the world can make it. There are 20 on each wing of each orbiter. The next generation 'space planes' are designed with ostensibly the same leading edge technology because there is little else better. The Japanese are trying to do better without RCC type materials. SiC 'structures' would be better, but no US company is making them. The rest of the story can be filled in without my help.

Dr. K

It's how we got Enron, Worldcom, etc. MBA's from prestigious universities will postpone maintenance, strip research budgets, "streamline" quality control, and pull a thousand other accounting tricks. They'll get a few really handsome quarterly reports, transfer to a higher paying job somewhere else, and leave those left "holding the bag" to take the long term negative consequences. That, combined with Alan Greenspan's "creative destruction" process to transfer our manufacturing base to China, and we'll be in a real fix pretty soon. I hope we can get out of it, but with the kind of students that the public schools are graduating, I have my doubts.-Jitney

Cycloneme, I would recommend the plant floor job too. When I do an efficiency study at a factory, the first place I look is the dumpster, a lot of employees hide problems there. People problems are the most common, and if there was a psychology course that I could recommend I would. Just go to the school of hard knocks and study for yourself, you'll learn more than you could in a classroom.-Jitney

Now................ I recommend starting a new thread with similar thoughts you gave before and allow the discussion to continue; thus establishing the type of dialog you sought in your original post. There is no preexisting theme or premise of this group. It is not moderated and I daresay questions not unlike a project or assignment for class have been too prevalent in this group lately. I also recommend expanding to all materials rather than just metals. Some experience from people that can never be captured by books, media or the web can now be made available for everyone through this group in a way never before possible. Funds for conferences have been cut back and I haven't been to any international ones for a year. This forum can partly substitute for that if done right. This group has a global audience. Many can learn from lurking. There is no danger that proprietary knowledge will make it to the group because the members of the group know better or it doesn't matter anyway. Most of us have web access and can post pictures (microstructures) elsewhere if needed. We might be able to support small images (< 10K) embedded in this non-binary group if needed. Let's go!

Dr. K

India ink is conductive. The

OK, lets' start a NEW thread ? : )

Dr. K

I've been in Failure Analysis for over 30 years and have a ton of interesting stories. Here's another one.

Our FRACA system revealed that a specific circuit board was suddenly being rejected for defective diodes. The problem was that the diodes retested good after removal. So did the circuit boards. So what was going on?

I went and observed the manual testing of these boards, many years before automated testing. I was able to verify the failures as they happened. I was also able to verify that the removed diodes tested good.

It dawned on me that the failures were occurring in the afternoon; this came from the time stamp on the reject notice. What did that have to do with it? Not all of the boards failed even then. It turned out that the diodes that were failing were clear glass ones. The diodes which were opaque did not fail. I then noticed that the afternoon sun shone on the PCBs that were being tested. Problem solved! When the sunlight was blocked, the boards passed!

Seems as the new lot of diodes had clear glass bodies. As they come into the production line, they started to fail, in the afternoon when the sun shone on them. As the boards were only used in enclosures, the solution was to block the sunlight during the production testing.

I just wonder what happened in the field when for some reason the boards had to be retested?

Al

A recent post asked for recommendations of introductory texts.

If you have time but no money you should download some articles.

A nice short one by Neville Sachs is "Root Cause Failure Analysis - Understanding Mechanical Failures" and can be found at:

Probably the best introductory textbook on failure analysis is Understanding How Components Fail, by Donald J. Wulpi and published by ASM International (2nd edition, 1999). Wulpi used to run the lab at International Harvester's truck division. He writes from the perspective of a practicing engineer rather than a materials scientist (college professor) like many of the other texts.

If you have more money than time, then you might instead consider taking the ASM online course on Principles of Failure Analysis for $395. If you have both lots of money and time, then you can take a whole week to do the ASM course at Materials Park in suburban Cleveland.

The standard reference book is the ASM Handbook (formerly Metals Handbook) volume on Failure Analysis and Prevention. There are three editions, a new green one (Volume 11, 2002), the older red one (9th edition, Volume 11, 198x), and the oldest blue one (8th edition, Volume 10, 1975). The older two include large sections of case histories of manufactured components and assemblies. The new one is more of an advanced textbook; it omits the case histories, since ASM has more recently published a two volume set of Handbook of Case Histories in Failure Analysis. Used copies of the old blue Metals Handbook occasionally show up used for reasonable prices (check eBay or

Failures often are caused by factors than what you might expect. For a taste of what can go wrong in the real world, see Trevor A. Kletz's book, What Went Wrong? Case Histories of Process Plant Disasters, Gulf Publishing Co., Houston, 2nd edition 1988.

Pittsburgh Pete

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Interesting indeed. By the way, a great article on paint problems was the 1998 Mattiello Memorial lecture by C.K. Shoff titled "Surface Defects: Diagnosis and Cure" in the Journal of Coatings Technology, Vol. 71, No. 888, 1999, p. 56. There also is Clive Hare's Trouble with Paint series that got collected as a textbook.

Pittsburgh Pete

I always wondered why, since diodes were prone to doing that, they didn't coat the glass diode shell when the cathodes were marked? Signal diodes were not used for photodetectors because their geometry wasn't optimized. But, in a pinch, they did work.. like for a laser beam on detector. I guess the youngsters don't have to worry because you don't see bare diodes on boards anymore.

Dr. K

I hear more and more how silicones get into things and mess them up. I also see more and more how silicones are the miracle additive for clothing, waterproofing everything, abrasion resistance, sticking other chemicals to surfaces as a carrier, protection for electronics, lubricants, ...and I can't be bother to keep going. Where is Armoral cleaner nowadays? It was my favorite silicone remover.

Dr. K