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cleaning of no clean flux

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#36031

cleaning of no clean flux | 10 August, 2005

we are using heareous F381, F352 no clean solder paste.

specially in qfp for high frequency board we observe that cleaing / removing of ' no clean flux 'is require. if we do not clean same most of time after all test & envioumental test it shows pin to pin contact short & if we clean ' no clean flux' pin to pin no short. is it necessary to clean ' no clean flux.

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#36033

cleaning of no clean flux | 10 August, 2005

Comments are: * Sounds like it's necessary to clean "heareous F381, F352 no clean solder paste" in your application. Consider a paste that may be better suited to your application. * If you're cleaning "low residue flux", consider using an organic acid flux? OA fluxes are much easier and cheaper to clean than low res. * Other RF applications have avoided cleaning of low res fluxes. Flux suppliers say things like: -- This material has been utilized on various assemblies with RF designs without cleaning; however, the compatibility of flux residues on RF assemblies is strongly dependent upon circuitry design. -- Post-process residues may remain on the PCB in RF designs without cleaning. Above 2GHz cleaning maybe required. -- Post-process residues may remain on the PWB in RF designs up to 10 gigahertz without cleaning. Above 10 gigahertz cleaning is recommended.

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jh0n!

#36035

cleaning of no clean flux | 10 August, 2005

Wasn't aware of that. We're using a no-clean with RF pcbs, and that's something to bear in mind for the future - thanks.

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#36054

cleaning of no clean flux | 10 August, 2005

The propensity for flux residues to cause shorts can be increased in humid environments where water molecules hydrate the surfaces. At high frequencies, electrons travel on the surface of conductors/insulators, increasing the likelihood of shorts in RF applications.

Steve Stach Austin American Technology Your Global Cleaning Experts www.aat-corp.com

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