Jaquelyn,
We use all of the IPC standards as our incoming inspection criteria, but
according to the people in our purchasing department these are bunk
standards and tell you nothing.
I fully understand that purchasing needs data to support our claims, which I
thought failing solderability testing per the J-STD-003 by two independant
labs would be sufficient.
I will continue to get cross section reports done to show that the typical
wetting issue can be masked with solder, but the issue is still there, just
buried under the solder. If the pad is not wettable there is no way you
will ever acheive a good intermetallic bond between the lead, the solder,
and the pad interface.
As a side note here -- I do consulting for a company which services ultra
sound equipment. I am setting up a rework/repair department. I have been
trouble shooting boards for him down to the component level. I have
reworked over 50 boards so far. I have not replaced one component yet. I
have simply touched up solder joints, and everyone of them have signs of
dewetting exactly like the solder joints that were created on the boards
that we are having dewetting issues on.
These boards see about 25 to 110 degrees celceuis temperature fluctuation,
which is not that far off from what our product would see. These boards were
only 3 years old before the solder joints started to fail.
Conclusion, just because you think it looks okay and it passes tests doesn't
always mean you have a quality solder joint connection.
Thanks,
Kathy Palumbo
Sr. Mfg. Engr.
Viking Components, Inc.
-----Original Message-----
From: Jebens, Jaquelyn [mailto:[log in to unmask]]
Sent: Wednesday, July 28, 1999 12:54 PM
To: 'TechNet E-Mail Forum.'; 'Kathy Palumbo'
Subject: RE: [TN] Dewetting Issues
Kathy,
What are your incoming inspection criteria for rejecting boards for
de-wetting
Or other solderability issues? I use one of the same board houses you do,
And just recently my incoming inspection has rejected boards for
solderability
And/or poor wetting. My incoming inspection has explained to me that this
Is just a visual inspection, and with their vast knowledge, they can just
"see"
The problem. As a buyer, it is very hard to return product without some
kind
Of evidence that there really is a problem.
Jackie Jebens
Purchasing Manager
GoldenRAM
-----Original Message-----
From: Kathy Palumbo [SMTP:[log in to unmask]]
Sent: Wednesday, July 28, 1999 12:45 PM
To: [log in to unmask]
Subject: Re: [TN] Dewetting Issues
FYI
They (purchasing) did not believe the solderability testing so they
had us
build up boards anyway. When the boards passed test they said there
was no
problem with the boards.
We all know this is not accurrate, because if you put enough solder
down you
can mask off just about any dewetting problem out there.
Believe me I have already pondered the worse case senerio!
Regards,
Kathy Palumbo
-----Original Message-----
From: Franklin [mailto:[log in to unmask]]
Sent: Wednesday, July 28, 1999 12:20 PM
To: [log in to unmask]
Subject: Re: [TN] Dewetting Issues
Kathy,
Why would you be concerned with 'long term solderability' issues
when you
have this initial solderability condition to deal with? Seems to me
the
argument should be the 'here and now', and not the 'what if'.
All I know about reliability studies are those I have first hand
experience
with, and that being as I wrote above, if they fail from the
beginning, they
will not get any better sitting on a shelf.
<smile> Something to ponder.
Franklin D Asbell, CQA
Network Circuits, Inc.
Irving, Texas
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