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Solder Reflow Problem

Pat Copeland


Solder Reflow Problem | 4 November, 1999

Just started having a problem with the solder on a board. Nothing has changed as far as profile, type of paste or setup. But yesterday we had the boards coming out of the reflow with horrible solder results. It appears on some components the solder is flowing away from the components. It is shiny in appearance, but bubbly in spots. Any ideas!!!

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Re: Solder Reflow Problem | 4 November, 1999

Sounds like you have a component problem! I say this because you say the sodler is flowing away from the components (leads I assume) This sounds like none wetting of the component. Do a solderability test on the parts. Take the parts and dip the leads into a bath off flux (try to use a flux similar to the one in your reflow process)then dip the leads into molten solder, see if the solder takes to the leads. Look for areas on the leads that did not take the solder. Check datecode on components!

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Re: Solder Reflow Problem | 4 November, 1999

Sometimes when using a new pot of paste you get one which isn�t good at all without any noticable appearance at first sight. You might try a new one. Despite the fact that you run the same profile as usual a defect of the oven of any kind unnoticed could change your profile. Better measure the profile to be sure. Sometimes changes in the environment, open doors, windows, temperature, airflow, humidity influence the result of reflow especially with open inline equipment. Also as mentioned by Chad contamination of parts and PCB. Finally the operators, yeah... they do as usual, nothing has changed, they have no explanation, they�re sometimes great storytellers. You might check the process and handling again.

Hope this helps


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