Electronics Forum | Sat Nov 08 08:16:45 EST 2003 | davef
We saw this quite a bit, I want to say 5 or 6 years ago, but it's probably more like 10 years ago. It's caused by poor solder mask crue. Talk to your board fabricator about solutions.
Electronics Forum | Fri Nov 07 12:48:31 EST 2003 | rholland
I have seen in the last couple of months more boards with a white hazing under the solder mask. I ran a few tests on a board to determine the cause of the white hazing underneath the solder mask. First I confirmed, or at least I think I confirmed, t
Electronics Forum | Sat Nov 08 09:42:22 EST 2003 | ethercom
Hi: I have seen this problem before. It is caused by improper curing of solder mask by the fab manufacturer. When you run the board thru' wave solder, and then wash the board, you see the problem of white residue. However, when you apply heat, you c
Electronics Forum | Mon Aug 21 19:38:33 EDT 2000 | Dave F
Eric: I�ll pass on the uV and ammonia, also. Thoughts are: 1 You�re correct that the temperature/humidity mix can be a big driver to latex peelable solder mask cure time, but don�t overlook material thickness. Dispensers put material in a very th
Electronics Forum | Fri Nov 09 16:58:30 EST 2001 | davef
Go for it!!! You were unspecific, but adding mask to a completed board could cause: * Increased paste thickness, if you have double thickness of solder mask. * Wrinkled and lifted solder mask under the component, if the solderability protection of
Electronics Forum | Sun Jan 23 03:23:09 EST 2000 | Rob Steltman
Hi We use a U-channel piece of high temperature silicon which is just pushed over the gold tabs before the soldering process. The silicon can be used over and over again. The advantages are that there is no mask on the board during the SMT process a
Electronics Forum | Tue Jan 15 10:35:08 EST 2013 | boriskilk
We would agree with Pete B about both the under etching as a possible issue and you will not be able to remove this gold. Another possibility is the solder mask (plating resist) hasn't been taken right to the edge of the pad.
Electronics Forum | Fri Jan 09 09:43:48 EST 2009 | boardhouse
Hi Simon, The main reason that it would probably be removed would be do to lack of clearance for a soldermask dam from pad to pad. typically if the clearance from pad to pad is under .008 the solder mask dam would be removed. Min recomended dam siz
Electronics Forum | Tue Apr 19 16:20:05 EDT 2016 | davef
Don't blame it on the poor paste thickness requirement [although I might go on to argue that it's could be a contributor to the issue]. Most likely you're the problem. About 70% of the time solder on gold fingers is caused by poor cleaning of screen
Electronics Forum | Wed May 16 15:40:56 EDT 2012 | davef
Here's some notes from a Bob Willis presentation Assembly of Flexible Circuits with Lead-Free Solder Alloy [Bob Willis leadfreesoldering.com] * Flexible Circuit Construction ** Base Material - 0.05mm Copper 18/18 um ESPANEX from Holders Technologies
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