Electronics Forum | Tue Jul 27 13:48:45 EDT 2004 | Ralf
Hi Recently i have noticed that after reflow (hot air oven) on the solder lands without components but with solder(screen printing) there is discoloration. It looks like gasolin spilled on the wet road (rainbow). Any idea and reason Ralf
Electronics Forum | Fri Oct 15 10:23:48 EDT 2004 | mrmaint
Matt, are there any discoloration of the pads on the raw boards. i have seen what we refer to as gray pads. Ran into this in the past and it turned out to be a problem at the board house with one of their dipping tanks. The proper levels for the proc
Electronics Forum | Mon Mar 07 15:35:35 EST 2005 | John M
It has been my experience that the standard Fr4 material (Tg 135c) will discolor when processed at the new higher temperatures required for the high tin alloys... We have been using the High Tg Fr4 (Tg 170c) for many years to ensure this does not hap
Electronics Forum | Thu Oct 25 05:58:52 EDT 2007 | reypal
Is there a standard to specify how many times a profile board can be used? if No, then could I say that it depends on the actual board appearance (discoloration,delamination etc.) then it's time to replace a new one. Thanks in advance for sharing.
Electronics Forum | Fri Aug 29 10:18:31 EDT 2008 | rrpowers
We saw this one time when we were trying to develop some lead-free product. It ended up being copper migration. Some of the pads had a brown discoloration and those that did would not wet very well. Your elemental analysis would have shown if ther
Electronics Forum | Sat Sep 13 09:36:53 EDT 2008 | davef
Lemme tell ya, those are weird looking pix. If OSP boards have not been dried properly prior to bagging and sealing, water can leak from via and ruin the OSP, which will turn black.
Electronics Forum | Mon Oct 20 13:17:05 EDT 2008 | jdumont
No pictures pre-paste. I have noticed on a few occasions a couple of boards that look like they have a slight discoloration on some areas of the board. Kind of like a shadow almost on the gold. Josh
Electronics Forum | Tue Feb 10 18:39:06 EST 2009 | solderq
Quick production (no "pasty" phase) > High joint surface quality > Good flux action > No discolored, corrosive, or substantive residue of any kind > Lead-free is not a concern ;o) Any input/ideas are appreciated. Thanks!
Electronics Forum | Sun Aug 16 19:46:48 EDT 2009 | abeasia
Hi Dave F. Thanks for the suggestion, will give it a try. With Appreciation, ABE.Asia
Electronics Forum | Fri Sep 18 07:32:53 EDT 2009 | karthikthebest
I agree with Graham cooper's input. Also note that the brownish color is incremental w.r.t to number of days you hold after the thermal cycle(example: after the reflow)so try to complete all thermal cycles ASAP to lessen the discoloring.
