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

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Solder pot contamination

Woodsmt

#29952

Solder pot contamination | 9 August, 2004

I am looking for data / info on how flux may contaminate the solder in a Wave. I have a customer who requires a no clean process. Our wave is equipped with 2 separate fluxing systems and I would like to use OA in one and the No Clean in the other. The issue is the belief there are residues in the solder pot from the OA flux which will contaminate the boards run with no clean. I would think the solder pot has burned off any residues and this is not an issue, especially if we maintain the solder pot properly. As we are using selective solder fixtures we should have no contamination from the fingers. Anyone have any thoughts or know of any papers on this subject?

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

KEN

#29961

Solder pot contamination | 9 August, 2004

I think OA flux left on the pot would quickly looses its activity and become part of the dross waste stream, and smoke stream for that matter.

Also, if your wave is setup properly your selective pallets will scour (push) the top of the lambda wave prior to soldering. Any contamination then is suspended in the liquid solder bath / fountain (but not for long with the density differences). If it is in fact always there why would it be ok for OA processes and not NC?

I would be more concerned with what is in your bath like copper, aluminum, iron, cadmium, nickel etc. (lead if lead-free).

Also, I have a copper FR-4 board on my desk that was OA fluxed with a very aggressive OA and then wave soldered back in April 2004. It was not washed. Ther is no evidence of dendrites, missing copper, tarnish, patina, buggers, nothing. Is this imperical? NO. I just wanted to emphasize that propper thermal profiles coupled with a reasonable flux process will consume (virtually) all activity in the flux and the wave foountain will scour the remaining residues. However, If I drip a couple of drops of this same liquid flux on the copper plate, there will be missing copper within 24 hours (at room temperature).

I have a dual flux wave. The biggest problem is keeping the fingers clean and the grease in good shape.

reply »

Woodsmt

#30113

Solder pot contamination | 18 August, 2004

Ken,

Thanks for your reply. It seems in line with all my other Inquires.

This message was posted Add this forum to your site! Click to learn more. the Electronics Forum @

reply »

Plasma Prior to Conformal Coating

Heller Industries Mark 5获得了 2015年中国SMT远见奖 - 回焊炉领域