Thermal Discoloration

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Hello everyone! We just completed some 16-layer boards an... - Jan 20, 2002 by Peterson

Help us visualize this better. * What color white [ie, ye... - Jan 22, 2002 by davef

Peterson

#18690

Thermal Discoloration | 20 January, 2002

Hello everyone!

We just completed some 16-layer boards and noticed (after wave soldering) that there are some unique, white-ish discolorations. It looks as if someone layed their finger at weird angles on the groundplane areas. It is NOT finger prints...it just looks like the length of a finger. We used no-clean...so it is not residue. Attempts to remove it with cleaning solutions were not successful. I believe it is due to thermal expansion of some sort. Any thoughts out there in SMT Land?

Thanks for your help!

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davef

#18701

Thermal Discoloration | 22 January, 2002

Help us visualize this better. * What color white [ie, yellow/white, green/white, a haze, etc.] are we talking about? * What size and shape are the spots? * Where are the spots located? * Etc

Help us understand what�s going on by describing the specifics of: * Your process. * Fabrication of your bare boards.

Can you post or send a picture?

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