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Tin Oxide on Solder Joints

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#69665

Tin Oxide on Solder Joints | 1 July, 2013

Recently on one product, I found a white residue on the solder joints only that is more of a gray in color. Our lab told us it was a tin oxide with an unknown organic. This is with a lead free OA paste and it only shows after wash.

Has anyone seen this before?

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#69666

Tin Oxide on Solder Joints | 1 July, 2013

Walter: The things I'd look at first are: * Temperature of the water wash. I expect the solution to be in the 140-150*F range [Check with your flux supplier for recommended temperatures] * Temperature of the boards when entering the cleaning process.

BR, davef

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#69667

Tin Oxide on Solder Joints | 1 July, 2013

So that is common when the temp on the wash is high?

The temp was adjusted for a flux that required a higher temp.

How much of an issue is this tin oxide?

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#69668

Tin Oxide on Solder Joints | 1 July, 2013

70 degrees when entering the wash.

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#69669

Tin Oxide on Solder Joints | 1 July, 2013

I consider tin oxide on solder connections to be a process indicator.

BR, davef

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