What do they tell you on a solder joint under a connector they can't see???
Rick
-----Original Message-----
From: Stephen R. Gregory [mailto:[log in to unmask]]
Sent: Wednesday, November 01, 2000 7:30 PM
To: [log in to unmask]
Subject: Re: [TN] Thru hole fill
In a message dated 11/1/00 8:01:07 PM EST, [log in to unmask] writes:
<< Our customer is resisting a change from 100% fill to the IPC-A-610,
Class 3, 75% fill. We are using an OSP and having to do a lot of rework to
achieve 100% fill. I know this has been discussed in the past (I've read
the archives) but I need to be able to get my hands on specific studies
that
have been done that show that 75% fill is acceptable. I think that if I
can
show our customer the studies that have been done he may accept the change.
Any studies related to the automotive or aerospace industries would help
also. Does anybody know what spec various automotive or aerospace
companies
are using? Can someone give a contact in one of these companies? This is
costing us a lot of pain (and money), any help would be very appreciated.
Thanks,
Dallas >>
Hi Dallas!
Let me say this, I feel your pain...boy, do I feel your pain! I have some of
the same problems, not because of OSP's, but because of big thermal
heat-sinks in the designs of some of the boards we build (big thick power
and
ground planes). Where the solder gets partially up the barrel and freezes.
You don't wanna' know what hoops I've jumped through to try and get full
barrel fill on these boards.
What's worse, even when I've tried everything at wave solder, it's even MORE
difficult to try and touch the joints up...these planes suck all the heat
from the soldering irons and I see some of my girls working together with
two
soldering irons (one on the top and the other on the bottom) trying to get
"the preferred" fillets...I ask myself; is all this worth it? Am I really
making a better, more reliable solder joint? My gut feel is no...do I have
any data to back this up? No. But I do have the opinions of other people who
are used to looking at all the Martin Marietta pictures, and who were
trained
at China Lake years ago, who say unless there's a topside fillet with full
barrel fill, the joint is no good...
Am I venting? I bet you can guess...
Werner is the Guru on this stuff, I've tried to share his contributions to
the list about solder joint reliability with some people here, only to get;
"That's not what I was taught in China Lake..." Go figure...
-Steve Gregory-
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