Hello Technetters,
Section 7.3 has a note that says that:
White residues resulting from no-clean or other processes are acceptable
provided
the residues from chemistries used have been qualified and documented as
benign.
I have some of these residues on boards that come back from assemblies, the
engineer
responsible for the project accepted the boards like that. I don't really
like this so if
anyone can give me precision on this mater, I'd appreciate.
JF
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Hinners Hans Civ
WRALC/LYPME
Sent: Thursday, June 08, 2000 5:08 PM
To: [log in to unmask]
Subject: Re: [TN] Laminate condition
Hi Barry,
Let me show the pic to a couple of people tomorrow.
It looks like a flux residue either mere surface contamination or the
byproduct of a chemical reaction - oxidation. It isn't concentrated around
the solder and the screws have halos around them.
What have you tried to clean it with and how? - soak, agitation,
scrubbing . . .
Do you have any characterization capability? - Chromatograph, FTIR . . .
IPC-A-610 Rev C Section 7.3 states that a white residue on the PWB
surface is a defect for all three classes.
Hans
~~~~~~~~~~~~~~~~~~~
Hans M. Hinners
Materials (Process & Manufacturing) Engineer
Warner Robins Air Logistics Center
Avionics Production Division
Manufacturing Branch
380 Second Street, Suite 104
Building: 640, Mail Stop: LYPME
Robins AFB, GA 31098-1638
Voice: (912) 926 - 1970 Fax: (912) 926 - 7164
mailto:[log in to unmask]
http://www.robins.af.mil
-----Original Message-----
From: Barry Gallegos [mailto:[log in to unmask]]
Sent: Thursday, June 08, 2000 3:16 PM
To: Hinners Hans Civ WRALC/LYPME
Subject: RE: [TN] Laminate condition
Thank you Hans,
It does not appear to be something like blisters.
I am attaching a pic.
Barry
-----Original Message-----
From: Hinners Hans Civ WRALC/LYPME
[mailto:[log in to unmask]]
Sent: Thursday, June 08, 2000 1:04 PM
To: 'TechNet E-Mail Forum.'; 'Barry Gallegos'
Subject: RE: [TN] Laminate condition
Hi Barry,
Is the white appearance in or on the laminate?
Are we talking a mechanical defect in the material or a
residue/contamination?
Does it change if you press on the affected area? (blisters)
Send me a pic (off-list of course) and I'll run it around our shop
if ya want.
Need more info.
Hans
~~~~~~~~~~~~~~~~~~~
Hans M. Hinners
Materials (Process & Manufacturing) Engineer
Warner Robins Air Logistics Center
Avionics Production Division
Manufacturing Branch
380 Second Street, Suite 104
Building: 640, Mail Stop: LYPME
Robins AFB, GA 31098-1638
Voice: (912) 926 - 1970 Fax: (912) 926 - 7164
mailto:[log in to unmask]
http://www.robins.af.mil
-----Original Message-----
From: Barry Gallegos [mailto:[log in to unmask]]
Sent: Thursday, June 08, 2000 2:14 PM
To: [log in to unmask]
Subject: [TN] Laminate condition
Dear Sirs, Madams, Guru’s.
I have an assembly that we processed thru SMT and then thru the wave
solder operations. Wave solder flux was with Alpha metals 856 water-soluble.
The assembly is exhibiting a white cloudy / milky appearance that looks
almost as if the laminate/solder mask has changed color. No matter how much
we wash this assembly, it will not go away.
Is this due to possible moisture in, around or under the solder mask
/ laminate. What is it and is it acceptable.
Any advice would be appreciated.
Yours truly, (wana-be guru.)
Barry Gallegos
Western Electronics.
208-377-1557
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