Hi All,

I have a question regarding the discoloration of the silk screen ink after
reflow.  What can cause it other than overheating during reflow?

Here is some background to this question.  We received a consigned kit,
processed it and shipped it about three months ago.  Our profile data shows
that the PCB did not reach peak temperatures above 216 deg C.  We have run
this product once prior with a peak temperature of 212 deg C and with no
reports of discoloration.

Our client has contacted their board shop concerning this and were told by
the board shop that the discoloration is due to overheating.  Are there
other variables that could account for this?

Regards,
Martin Butcher,
Process Engineer.

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