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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Fog Test

blnorman

#20893

Fog Test | 26 July, 2002

Is anyone aware of a fog test for flux or flux residues? Supposedly one of our vendors had a test, but we've lost the specifics. We're interested in finding out if after heating, some of the residues (retained volatiles, or whatever) will escape and condense on a surface (like a lense). Anybody know of a test? There is an ASTM for Volatile Condensable Materials, but that is driven by vacuum, not temperature.

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#20894

Fog Test | 26 July, 2002

Never heard of flux residues forming a lense. The first thing that comes mind when thinking about your 'fog test' is: Ionic Contamination

While this seems pretty far afield from your interest in optical effects, I'll continue briefly. A reverse plating cell that produces electromigration requires: * Bias voltage. * Moisture. * Active ionic material.

Anyway, consider poking around TM-650 for a test to your liking, maybe 2.6.14.1 Electrochemical Migration Resistance Test.

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blnorman

#20896

Fog Test | 26 July, 2002

Actually this is for an automotive instrument cluster. From what I've been told back in the good old days we switched fluxes and after the car sat in the sun (and heat) a haze developed on the inside of the panel that was attributed to the flux.

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#20907

Fog Test | 28 July, 2002

'Good Old Days', hummm, sounds dangerous from the start.

Dunno, Bill. While they're corrosion oriented, but have you considered: * ASTM D2247, Procedure for Humidity Testing * ASTM B117, Procedure for Salt Spray Testing (Fog Testing)

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CAL

#20918

Fog Test | 28 July, 2002

Contact Greg Wood at ACI/EMPF. gwood@aciusa.org. Greg will be able to find out the deal.

Also, I was part of VDO America who made instrument clusters for VW, BMW, Bombardier, and such and put many instrument clusters through accelerated testing and never heard this being an issue. I cant imagine there is any volitiles left by the time the car hits the sun.

This flux is from Electronics? and not a mold (flux) release from the plastic molded parts?

I know we have found in humid contitions the number on the indicators would smear.

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