Impressive documents, Jay,
however, like MIL papers, could be shortened to just a fraction of all those pages.
Comments:
8739.3 Soldered electrical connections (61pages!)
Table 7-1 page 38 Solder joint contaminations, listed max levels of...
Very ambitious! Question is, do you really check that daily? I'm aware this was
a somewhat too hard question and expect no answer. I think few of us check the
soldered assemblies so thoroughfully.
8739.3 12.2 Preparation and Assembly. 'Only PWBs with Tin/Lead solder coated or reflowed
....patterns shall be wave soldered'.
Won't the conditions be changed even for NASA? Exemptions are not for ever.
I have compared the content with our own standards for soldering, and both are
likewise old fashioned. I would like fresh ideas. Why not a CD for each operator, with
sharp photos, movies and human voice comments? Arrrrgh...I'm going too far..
Thanks, Jay,
it's a great thing that NASA are willing to share with us...like our own SPACE
DEPT, both being years after the consumer and toy technology (e.g. still using lots of
metal canned 2N2222 in rocket computer..), but like a true cup of
tea: familiar and safe and reliable....
Ingemar Hernefjord
Ericsson Microwave Systems
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]
Sent: den 30 mars 2005 14:54
To: [log in to unmask]
Subject: Re: [TN] Solder Terminals + NASA Workmanship Std www site
Bill Brooks inquired about assorted standards that address workmanship
criteria for solder terminals. The NASA Workmanship Standards www site
provides access to a handful of NASA stds including NASA-STD-8739.3 for
"Soldered Electrical Connections"
http://workmanship.nasa.gov/wkstds_nasa.jsp
The site also includes a very informative "Inspection Pictorial Reference"
derived from a variety of sources including NASA, IPC and other
organizations. This reference provides illustrations and photos of a wide
range of electronics assembly workmanship practices including citation of
acceptance/rejection criteria within the NASA std. Many examples of solder
terminal applications are included as well as examples of conformal
coat/staking, crimp connections, fiber optic assembly, et al.
http://workmanship.nasa.gov/insp.jsp ( read the
description/disclaimer of this "inspection pictorial reference" )
http://workmanship.nasa.gov/lib/insp/2%20books/frameset.html ( to
open the actual pictorial reference )
Cheers,
Jay Brusse
QSS Group, Inc at NASA Goddard Space Flight Center
----
Date: Tue, 29 Mar 2005 09:00:26 -0800
From: "Brooks,Bill" <[log in to unmask]>
Subject: Re: Solder Terminals
Hi Robert,
Yes... I recall the acceptability of cracks in terminals and eyelets...
Thanks for the reminder. It's been a long time since I have had to deal with
them. Your last comment on PTH swaging of terminals... I thought they didn't
allow that in the Mil Specs... there was an issue with damage to the PTH I
think... We always added multiple vias around any non-plated or plated
mechanical hole that was used for ground and/or mounting or if the board
was under any mechanical compression so as to guarantee that the continuity
of the pads on top to the planes and pads on the bottom was maintained by a
via free of mechanical compression... regardless of any single failure in a
mounting or swaged terminal hole. It was just 'good insurance'.
Do you have the specific spec numbers for those? I'd like to look at them
again.
Best regards,
Bill Brooks - KG6VVP
PCB Design Engineer , C.I.D.+, C.I.I.
Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510
e-mail:[log in to unmask]
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