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blackened/black solder

Views: 1112

#48703

blackened/black solder | 28 March, 2007

I am having problems with a product we receive from our overseas plant, where there is excessive "dullness" of solder joints/metal surfaces after running a board on a pallet through wave solder. Seems to be an issue of the pallet, as the solder appearance out of SMT is fine, but after the wave is not.

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#48705

blackened/black solder | 28 March, 2007

Hi A,

Your subject is black solder, but you decrribe the solder as dull? Dull solder joints could be dross related, or even flux related. Are there any other related defects? But "dull metal sufaces" makes me thing this board was subjected to something.

I doubt if the pallet has anything to do with it.

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#48707

blackened/black solder | 28 March, 2007

It should only be a visual thing. What may be happening is that all the thermal energy being driven into the wave solder pallet to get good soldering is causing the no-clean residues to burn up a bit, causing the discoloring. Check to see if they have topside preheater(s) on the wave. It is possible that the SMT is getting reflowed. Do they have a thermal profile for the wave solder process that they can show you? You want to see how hot the top side of the board is getting and for how much time.

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#48710

blackened/black solder | 28 March, 2007

solder joints are dull on the bottom, and surprisingly, darkened, "black" on the top, especially at one location only.

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#48711

blackened/black solder | 28 March, 2007

Unfortunately, the facility overseas does not have a profiler. We suspect it is overheating due to a thick pallet and a raised temperature to compensate for it.

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#48715

blackened/black solder | 28 March, 2007

They were run with dross inhibitor in the pot.

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