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Refreshing PCB Solderability

Kevin Facinelli

#21170

Refreshing PCB Solderability | 14 August, 2002

I have a PCB laminate that is 1 1/2 years old and showing signs of poor solderability. The NC flux I am using will not breakdown the oxides. During hand soldering the pads do not take solder. I am trying alternative fluxes and have seen an improvement but still not getting the desired wetting. Is their a cleaning process for improving solderability? I looked in the achives and can't find an answer....

Thanks,

Kevin

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dragonslayr

#21171

Refreshing PCB Solderability | 14 August, 2002

What is the surface finish? HASL, Entek? what?

If HASL, ask your fab supplier for recommendations, maybe even rerun the boards through the HASL process. The fab house would have to strip off the old coating and reapply.

Just a thought, depends on your urgency and willingness to try alternatives. I'm sure others will want to give valid reasons to be cautious, regardless of rework method you can pursue.

Why not trying brushing on some paste flux and run the boards (unpopulated) through the reflow oven. It seems to me a water soluble paste flux would clean the pads, then you wash the boards, bake them and begin with the regular paste print, place and reflow process. Your flux vendor may have an aggressive flux to help you with a rework of the pads.

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#21175

Refreshing PCB Solderability | 14 August, 2002

Search the fine SMTnet Archives. I recall something about EMPF and ROSA.

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CAL

#21189

Refreshing PCB Solderability | 16 August, 2002

Dave- once again you are correct. ACI/Empf (www.aciusa.org or http://www.empf.org) have a process to electrochemically revert the process back to a usable form. contact Greg Wood at ACI 610-362-1200.

Cal

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Kevin Facinelli

#21197

Refreshing PCB Solderability | 16 August, 2002

Thanks guys......

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