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I encountered the mindset that started this thread too. This from NASA
trainers as they were introduced to J-STD-001. They were resistant to the
wave solder process. Bill, I empathize.
I do think one could make a case for hand soldering on thick boards with
high aspect ratio PTH, rather than subject a very complex and difficult to
fabricate board to multiple passes at reflow temperatures.
Werner, in such a case, don't you think it might be possible to hand solder
SMT leaded parts and leadless passives with less strain at the PTH?
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier
Sent: Friday, September 14, 2007 12:46 PM
To: [log in to unmask]
Subject: Re: [TN] Military/NASA Spec Question
Hi,
If properly done, there is no reliability difference for hand- or
machine-soldered solder joints. HOWEVER, handsoldering subjects the PCBs to
higher temperatures with larger temperature gradients, and thus there are
reliability differences as far as the whole assembl;y is
concerned-hand-soldering should be m inimized to the largest extent
possible.
Werner
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