Although the true answer is in a state of flux, I do agree with what
several have said. I have seen it in the past and called it nodule-ing.
All other things being equal, it was determined to be cosmetic in
nature, but noted as a process indicator for potential trend analysis.
It was determined that the bandwidth for flux activity effectiveness
fell outside the optimal targeted process window. I used these words so
that the several sick sigma teams formed could all come up with their
own right answer to fix a problem that never existed in the first place.
Now it's time for a "Santa"ty check for other hidden clauses in what I
say.
If the Air Traffic Controllers shut down flights at Midnight, Dec.24th,
would that be a "pause for the Claus"?
Since we were initially dealing with spheres of influence, I would like
to take this opportunity to thank all of you for your many contributions
to this forum. It is rewarding for me personally, because your responses
indicate I have had an impact on this forum.
To all of you and the traditions you uphold, I wish the best for this
Holiday Season and a joyous and fulfilling New Year to come.
Dewey
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of John Burke
Sent: Friday, December 14, 2007 1:29 AM
To: [log in to unmask]
Subject: Re: [TN] "Grape-ing" update 1
I have seen this on a number of occasions and would offer the following
advice:
In this (somewhat unfortunate) condition, the solder spheres are at some
point getting hot enough to reflow but at this point you are just about
out
of flux activity due to the activity having been virtually "baked out"
during the ramp.
Corrective actions are to get to reflow temp faster and make sure that
the
temperature is adequate to actually get the joints into reflow.
This condition is actually more predominant on small components where
the
amount of solder (and hence flux to break down oxides) is somewhat
limited -
you will see it first on components such as 0201's.
Sorry if this data has been already supplied - I am on a road trip
bringing
my Daughter back from college - have stopped at a motel - just drove the
width of Texas - wow that is one large State........
Back in CA sometime very late tonight.
John Burke
(408) 515 4992
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Phillip Bavaro
Sent: Thursday, December 13, 2007 3:44 PM
To: [log in to unmask]
Subject: Re: [TN] "Grape-ing" update 1
This month started with concerns about passives not having bright silver
shiny solder connections (and we all know that is a thing of the past),
and
now we have grapes.
We don't have any failures at all related to either of these two
cosmetic
issues, and there are a myriad of surface finishes involved altogether.
My response, so far, has been to stick to IPC terms and
definitions........and from what I have seen so far, the connections
exhibit acceptable wetting so this is purely a cosmetic issue for now.
The root cause, according to some sources is supposed to have to do with
exhaustion of the flux vehicle during reflow...but that is contradictory
to
the second theory offered that the time at reflow was not long enough to
allow proper melting.
I will keep you posted as I "learn" more. BTW, it is Friday in China.
At 01:22 PM 12/13/2007 -0800, Miguel Vallejo wrote:
>Poor wetting seems to fit the bill, why call it something else..?
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Dale Ritzen
>Sent: Thursday, December 13, 2007 11:56 AM
>To: [log in to unmask]
>Subject: Re: [TN] "Grape-ing"
>
>See attached CircuitNet answer (Ask the Experts) by Neil Poole for
>definition (beings as it's not Friday yet)...
>
>http://www.circuitnet.com/articles/article_40078.shtml
>
>Dale Ritzen
>Quality Manager
>Austin Manufacturing Services
>
>-----Original Message-----
>From: Stadem, Richard D. [mailto:[log in to unmask]]
>Sent: Thursday, December 13, 2007 1:05 PM
>To: [log in to unmask]
>Subject: Re: [TN] "Grape-ing"
>
>
>Never heard of it. If your paste supplier is educating you, shouldn't
>you be enlightening us?
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Phillip Bavaro
>Sent: Thursday, December 13, 2007 5:06 AM
>To: [log in to unmask]
>Subject: [TN] "Grape-ing"
>
>My solderpaste supplier is educating me regarding a defect called
>"grape-ing".
>
>Anyone care to shed a little light on this soldering defect?
>
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