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Flux Compatibility Issues....

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#41976

Flux Compatibility Issues.... | 5 June, 2006

I was wondering if anyone could help point me in the right direction on this one. This morning I discovered that our hand solder operators have been using the liquid wave solder flux for some hand soldering operations. We are using Kester 245 63/37 no clean wire and they are adding Multicore liquid wave flux. I told them to stop doing this until I get some answers from Kester. In the meantime I was thinking someone here could help me out.... Apparently they have been doing this for years so I dont think its caused any problems but I need to be sure. Any suggestions??

Thanks in advance...

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marc

#41981

Flux Compatibility Issues.... | 5 June, 2006

Yes.... stop checking on your process.... :)

Seriously...if you cleaning the boards after I would suspect no issues. If your leaving the flux on the board (I suspect they are using quite a bit) then I would be concerned.

Since the boards have already gone through a reflow cycle or two the oxides may be tougher to get off, thus why they started to dip into the wave flux for the rework operation.

I would have them run a couple with and without the flux, check the results. They have basically trained themselves to solder with the extra flux (wider process window), now that is gone, I would be a bit concerned about the soldering.

Good Luck

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#41988

Flux Compatibility Issues.... | 6 June, 2006

Thanks for the reply. I actually heard back from Kester who say they dont test with other fluxes (obviously) but that there shouldnt be any issues. Of course they recommended their wave flux to replace our Multicore and can confidently then say there will be no issues doing this. I think based on historical data I will allow them to proceed using the wave flux (sparingly). Thanks for the help...

If anyone wants to see their answer official answer let me know.

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#41990

Flux Compatibility Issues.... | 6 June, 2006

Wave flux, although I've seen it used successfully in my past life, is not such a good idea to use as a rework/touchup flux. Wave flux needs to be heated to certain activation temps which won't be repeatedly achieved with a manual soldering process. Plus, you won't burn off any residual activator as you would if the board were immersed in a solder bath.

If you want peace-of-mind, do your due dillegence and have the boards tested for Ionic Cleanliness. Run them through your normal "rework" process and then have them tested.

For rework flux, ideally you should use a no-clean flux pen, which I believe is a different formula than wave flux. All flux manufacturers including Kester offer this.

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#41991

Flux Compatibility Issues.... | 6 June, 2006

For some, not all, hand assembly, we use additional flux. We use a flux pen in certain applications and liquid flux in other applications - you can't just say switch to a flux pen, it isn't always adequate. Most flux pens are ORL0 with very low solids content. The liquid flux is more often ROL0, with a higher solids content, but can still be classed as no-clean. We run a no-clean process, but any flux added for hand assembly is always cleaned. No-clean flux in your paste, or wave assembly process that has been thru the full automated process should have all been adequately heated to render it inert, but when manually added for hand assembly, there is always flux that has not been fully heated left on the board. That is why we clean.

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Wave Master Larry

#42013

Flux Compatibility Issues.... | 7 June, 2006

Listen Samir, we some times spray the tops of our baords at wave to achieve top side wetting. Not sure if the engineers aren't setting up the wave right or not, but it gets the jwob done. We don't see any fall out from this and have been doing it for years off and on. I always set the fluxer up to spray minimal flux to the bottom, so adding a little to the top would just even things out.

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Loco

#42022

Flux Compatibility Issues.... | 8 June, 2006

\o/ Wohoo the WML is back!!!

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RDR

#42025

Flux Compatibility Issues.... | 8 June, 2006

Why would a "Wave Master" require an engineer to set up his machine?

How could a wave master misunderstand mixing flux types with squirting the same flux on the top of a board?

I am losing my confidence in Wave Master Larry!

Russ

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#42034

Flux Compatibility Issues.... | 8 June, 2006

We don't agree that "a little to the top would just even things out". The raw flux on the top of the board never touches the wave and so, does not receive the proper amount of heat for activation, except at the through hole barrels. * We assume WML can "get away" with manual top-spraying his boards is because he uses OA flux and washes the excess unactivated flux during cleaning. * Otherwise, uncontrolled application will leave unexpectedly high concentrations of low residue flux, which could affect product performance.

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#42065

Flux Compatibility Issues.... | 9 June, 2006

I say:

�Wave flux needs to be heated to certain activation temps which won't be repeatedly achieved with a manual soldering process. Plus, you won't burn off any residual activator as you would if the board were immersed in a solder bath.�

Muse says:

��No-clean flux in your paste, or wave assembly process that has been thru the full automated process should have all been adequately heated to render it inert, but when manually added for hand assembly, there is always flux that has not been fully heated left on the board. �

�and Mr. Dave F says:

�We don't agree that "a little to the top would just even things out". The raw flux on the top of the board never touches the wave and so, does not receive the proper amount of heat for activation, except at the through hole barrels.�

So, 3 professional opinions� Larry, how can the 3 us be wrong that it IS wrong to spray the board on the top-side? GOSH! IDIOT!

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Wave Master Larry

#42073

Flux Compatibility Issues.... | 9 June, 2006

That's easy I let the final yields speak for themselves.

Now your all professionals? OK, then why is it you guys get mad at others for prompting there own names like doctor or guru?

You can call me an idiot but name calling is for the birds.

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