Use a spray fluxer at low flow rates. There is very little solvent left by
the time the flux hits the panel at the low flow rates available. At a
prior employer we used this type of pallet to mask SMD that could not go
through the wave and never had residue problems. We always spray fluxed.

There also are a dozen or so companies that design and build custom pallets
like you describe (with conductive composite available). Call one of them
for design improvements.

Foam and wave fluxing with some fluxes will almost always weep to some
extent.
-------------
Original Text
From: C=US/A=INTERNET/DDA=ID/msaw(a)borg.com, on 3/22/98 7:38 AM:
I am currently trying to design solder masking pallets to eliminate the
need to use latex masking on the solder side of PTH boards. My problem
is that I cannot figure a way to keep the flux from weeping between the
pallet and the shielded portion of the boards. We are using a no-clean
flux in our process and this is leaving a residue on the masked areas.
The pallets are constructed of FR4/G10.
    Does anyone have any experience with a situation similar to this?
    Any help would be greatly appreciated.
                                                                Mark A.
Warycka

Manufacturing Engineer
                                                                The
Partlow-West Company
                                                                 New
Hartford,NY

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