Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

Problem with flux

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Problem with flux | 20 August, 2009


I am having a problem with the flux in the wave solder, I am using a sonoflux 9000 this machine uses a air knife to spray the flux, it creates a mist that when hits the air knife pulls the mist up to the pallet where the board is, but for some reason after the wave is leaving a light whiteish residue, and the QA guy is making me clean it, even after showing him the spec sheet of the flux, I am using 951 Kester flux is Alcohol base, can these residue can be a problem???


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Problem with flux | 20 August, 2009

Questions are: * On what portion of the second side of the board [eg, solder only, solder mask only, etc] do you see this white hazy residue? * Could you attach a picture? * You mention cleaning this residue. What have you used to clean the residue?

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Problem with flux | 20 August, 2009

Hi !

In both solder mask and solder joint, I am going to upload a picture today promise, I use only IPA and a ESD brush this kinda clean the problem

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Problem with flux | 20 August, 2009

Hello Armando,

this is what I found into the handbook "Failure Analysis of Electronic processes" :

"...Flux residues with water-soluble flux activators that are conductive and corrosive if left on in large enough quantities are detrimental. If you can see it, it appears to be high enough to be a concern (with water soluble fluxes only, not No Clean flux residues)...".

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hi ghepo

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Problem with flux | 20 August, 2009

Armando: We're guessing that the white residue is on the laminate also. We believe that the residue has something to do with your low residue flux and water. It could be: * Water contamination in the flux. * Poor selection of preheat temperature that does not fully vaporize water in the flux. * Humidity in the air that is some how condensing on the board prior to soldering.

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