Steve,
I would be concerned about the mask integrity. Do you have any higher
magnification pictures you can post on your site? If in fact the blisters
are just on the surface the board my be OK. What type of environment will
this board operate in? If the board is not going to see a harsh environment,
I would be less concerned.
Bob Metcalf
Circuit Solutions
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Stephen Gregory
Sent: Wednesday, June 08, 2005 10:53 AM
To: [log in to unmask]
Subject: Re: [TN] Tiny Blisters on dry-film soldermask
Hi Bob!
Boards that have been touched-up or hand soldered with RMA
flux, are cleaned within the shift....that's the way it's supposed to
go anyway.
I wouldn't have thought it would attack the mask either, and yes,
it is just only on the surface.
We clean with Kyzen Aquanox 4512P mixed with DI water.
One more question, is the board history now? Has the mask been
compromised? This is a class-3 radar assembly that doesn't get
coated.
Kind regards,
-Steve Gregory-
Senior Process Engineer
LaBarge Incorporated
Tulsa, Oklahoma
(918) 459-2285
(918) 459-2350 FAX
|---------+----------------------------->
| | "Bob Metcalf" |
| | <Bob@CircuitSoluti|
| | onsPCB.com> |
| | |
| | 06/08/2005 12:43 |
| | PM |
| | |
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| To: "TechNet E-Mail Forum" <[log in to unmask]>,
<[log in to unmask]> |
| cc:
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| Subject: RE: [TN]
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Steve,
How long did the flux sit on the board before wave soldering? RMA fluxes do
not normally attack the solder mask, however RMA's contain alcohol and that
will attack the solder mask. Long exposure prior to soldering could lead to
the type of surface attack (assume surface only) you are seeing.
What type of cleaning followed the soldering?
Bob Metcalf
Circuit Solutions
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Stephen Gregory
Sent: Wednesday, June 08, 2005 9:08 AM
To: [log in to unmask]
Subject: [TN]
Hi All!
My turn to post a picture today...hehehe.
Have this very strange problem with my good ol' freind
dry film soldermask...eh, what's new?
Take a look at; "Mask Blisters, and Mask Blisters 2" on
my page at: http://www.stevezeva.homestead.com
These are very little tiny blisters on the backside of a built
assembly. The board was baked and it was wave soldered.
The blisters don't appear on the topside of the board at all.
The soldermask is Dupont Vacrel 8140. The little blisters appear
everywhere there's been touch-up done. It's not just around the
solder joints, but it looks like the blisters appear where ever flux
has contacted the mask.
The liquid flux that we use for touch-up is Alpha 615 RMA.
What in the world could cause this sort of thing?
Kind regards,
-Steve Gregory-
Senior Process Engineer
LaBarge Incorporated
Tulsa, Oklahoma
(918) 459-2285
(918) 459-2350 FAX
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