Now that's an explanation for which I've been looking hoping it is real.
We've covered this ground so much without enough comfort as I still get
random, killer, problems from reputable suppliers. It's enough to make you
want to return to HASL and I damn well don't want that, but the best fix
I've found is to strip the gold and HASL to save the farm and kids. Now what
say all ye chemical types on this forum? As another gentleman so afflicted
said, "where's the beef?" or something to that effect.
Earl Moon
----- Original Message -----
From: Robert Peterson <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, October 12, 1999 10:31 AM
Subject: Re: [TN] Black Plague
> Hi,
>
> There is an article by Nicholas Biunno of Hadco on page 133 of Issue 5 of
> "Future Circuits International" that covers the "Black Plague" quite
> thoroughly.
>
> Here is a very short over simplified summary:
> Everybody looks at the nickel but the cause turns out to be the immersion
> gold is too aggressive. The immersion gold works by corroding the nickel.
If
> it is too aggressive it takes away the nickel and leave phosphorous
behind.
> This makes it look like the phosphorous level is too high in the nickel
> bath.
>
> Robert Peterson
> mailto:[log in to unmask]
>
> Alternate Final Finishes, Inc.
> 166 Middlesex St.
> N. Chelmsford MA 01863
> Phone (978) 251-7429 Fax (978) 251-7219
> http://www.AlternateFinalFinishes.com
>
>
> -----Original Message-----
> From: Hollandsworth, Ron [mailto:[log in to unmask]]
> Sent: Tuesday, October 12, 1999 11:21 AM
> To: [log in to unmask]
> Subject: Re: [TN] Black Plague
> Importance: Low
>
>
> Franklin
> We are seeing the problem mainly at our wavesoldering operation. We have
> seen some, little, at the SMD workcell. We have checked our wavesolder
> process and profile and it has not changed. The problem is lot number
> dependent. A specific date code may have multiple lot numbers, and the
> issue show up on one lot number only and not every board in the lot. Bare
> board condition shows no early warning signs that we have detected at this
> time. We have cross sectioned some boards to see if there may be a tell
> tale sign, but nothing outstanding. We do have a couple boards in for
that
> cross sectioning at the present time. No data back yet.
>
> Ron
>
> -----Original Message-----
> From: Franklin [mailto:[log in to unmask]]
> Sent: Tuesday, October 12, 1999 9:41 AM
> To: [log in to unmask]
> Subject: Re: [TN] Black Plague
>
>
> Ron,
>
> Where are you first seeing this condition?
>
> Is it on the bare boards?
>
> Are the the assembler or fabricator?
>
> How have you 'cleaned' these boards up in the past, if at all? (cleaned or
> made the gold look better)
>
> I'd like to offer whatever I can, your first message just did not have
> enough information.
>
> Franklin
>
>
> -----Original Message-----
> From: Hollandsworth, Ron < [log in to unmask] <mailto:[log in to unmask]> >
> To: [log in to unmask] <mailto:[log in to unmask]> < [log in to unmask]
> <mailto:[log in to unmask]> >
> Date: 12 October, 1999 7:54 AM
> Subject: Re: [TN] Black Plague
>
>
> Franklin, POD, & Paul
> You say there are ways to get around the Black Plague. Would you
elaborate
> please. Once again I see messages where others are experiencing this
> problem but no absolute solutions. I have read the articles, tried the
> erasers, stronger fluxes, and pad scraping. No relief. I have learned to
> dislike Electroless Ni/ Immersion Au boards. I am thinking that HASL or
> precision pad technologies are much better. At least you can perform your
> soldering operation. A Circuit Card Assembly (CCA) with the Black Plague
> can run up scrap costs real fast. Not to mention the possibility of late
> shipment to the customer because of inability to solder. This is a real
> problem if you are using Ni/Au boards. So far there are few comments and
> the issue simply drops out of sight. Are platers/fabricators not
> controlling their processes or is this a inhouse process issue. We have
> checked our processes and find no change.
>
> Ron Hollandsworth
>
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