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Date: | Sat, 1 Dec 2007 11:41:09 +0200 |
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Do you mean a no-VOC flux or one using alcohol as the solvent? If the
former, then all the components in it must be water-soluble, but not
necessarily the residues.
You have a combination that spells disaster. I know a European telecomms
company (a customer of my former company) that had to recall several
millions ¤¤¤ of 8 layer backplanes going into street boxes for just the
same reason, although it used the most active alcohol-based "no-clean"
flux it could find for easy soldering. It changed to water-soluble, good
cleaning equipment, contamination control and conformal coating. No
problems after that. Overall cost was not much different because the
retouch rate dropped dramatically with the W/S flux, as it had problems
with solder rise in the PTHs with the NC flux (internal layers slowing
down the rise to the extent of flux inactivation).
One of the flux manufacturers (Alpha or Multicore?) used to sell heat
resistant glass plates to determine flux deposits. You put it on the
conveyor like a board and you could see what residues were left after
"soldering" it. You could appreciate them either visually or with a
simple photometer. Also excellent for showing latitudinal uniformity.
May be worth exploring.
Brian
Joel Alexander wrote:
> Hi guys its me again,
>
>
> We have a customer that builds power systems for the Telcom companies.
> They recently had a field failure on a backplane. It had sever corrosion.
> We process the assembly with a VOC no-clean solder and have never had
> issues in the past. The customer indicated that the backplane was in a
> damp/moist environment. That is not a good combination for no clean flux.
> I suggested cleaning but they insisted that we monitor our flux volume to
> ensure it is at the recommended application volume. I did not really agree
> from a reliability standard.
>
> Does anyone out there measure their no clean flux volume on a regular
> basis?
>
>
>
> Joel Alexander
> Quality Assurance Manager
> TT APSCO, INC.
>
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