Interesting NASA article, Steve. 1st table mm, must mean mils, don't you think?
With respect for all math work done, I'm still astonished that solder joints work as good as they do. Have not seen many failures during my many years in the game. 1st real experience I had was from Philips early TV days, when they began to use PTH mounted line transformers. These were 'hanging' in the solder joints, and those joints became real trouble makers after some years. Mechanical force, heat change (old line transformers had high heat dissipation)and solder did not match, and famous fatigue creeping occurred. The final result was open circuits. Later problems have been RF power transistors and their solder joints, basically with same failure parameters as the line transformer. In both these cases, increasing the solder joint thickness would have little success, because the concepts were too much outside the normal process window. Except from these extremes, I have seen very few failure cases connected with solder joint height. Some ought not to work, e.g. ceramic co!
mponents soldered with meagre solder joints on teflon/brass boards, but the products work perfectly after a decade or more in fierce environment. As I said, it's a miracle, that ordinary solder joints work as good as they do, irrespective of the solder joint thickness.
Ingemar Hernefjord
Ericsson Microwave Systems
-----Original Message-----
From: Stolar, Paul W [mailto:[log in to unmask]]
Sent: den 1 oktober 2003 21:45
To: [log in to unmask]
Subject: [TN] Reliability solder
Paul Stolar
Materials Engineer
Houston Technology Center
Baker Atlas
713-625-5376
713-625-4949 (fax)
Has anyone ever done any experiments to determine the effect the solder
thickness under a lead has on the joint's reliability?
Paul Stolar
Materials Engineer
Houston Technology Center
Baker Atlas
713-625-5376
713-625-4949 (fax)
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