Steve,
I totally agree with Brian's statement, as far as the undercure of
soldermask.
Question
1. Do boards both have the same date code-if not this would support the
undercuring of mask.
2. What type of LPI soldermask is being applied- glossy or matte. The matte
finish
soldermask has more of a tendency to give you the "milky/hazy" appearance
after wave, which
allows moiture to introduce itself. Not to get too technical, but the matte
has microscopic air
pockets which gives it the matte appearance. Some assemblers prefer matte
when fine pitch
surface mounts are involved to prevent solder-balling.
The pictures that you show although, is much more extreme than this
condition.
Adios
Tony Steinke
----- Original Message -----
From: Stephen R. Gregory <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, February 07, 2001 5:30 PM
Subject: [TN] Ebony and Ivory...
> Hey All!
>
> Wave soldered three boards today, all the same assembly, same profile,
etc.,
> and after wash one board looked all milky white on the bottom, they all
> looked the same coming out of wave though...when comparing it to the other
2,
> it was like Ebony and Ivory...go to:
>
> http://www.driveway.com/share?sid=4eced0a4.94f42&name=Pictures&view=3
>
> And you see what I mean. I've got a close-up on Ivory too. Mask seems
intact,
> and everthing else seems okay except for the milky color... the "Ebony"
looks
> like it almost was going to do the same thing, because you can see the
> outline of the wave solder fixture in it, but it didn't. On "Ivory" you
can't
> miss the fixture outline...what in the bajeebers would cause something
like
> this? Is the board scap? It's class-2.
>
> I tried baking to see if would do anything but it didn't...
>
> Thanks!
>
> -Steve-
>
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