Jim - I'm not sure I fully understand what you are saying here. At first I
was thinking it was contamination in the hole and that you were not wetting
the inside of the hole, but then you said the cross-sections looked good
without any voiding. The next thing that comes to mind is that the hole is
too big for the lead going through it and good old gravity is taking over
while the solder is still liquid. To verify, what is the O.D. of the lead
and the I.D. of the hole?

Your problem could also be from other factors which are hard to determine
without having a more detailed description or actually seeing the operation
(Caveat). I hope this may help.

Ed Valentine
Electronics Manufacturing Solutions
8612 Mourning Dove Road, Raleigh, NC 27615
Phone: (919) 270-5145, Fax: (919) 847-9971
Email: [log in to unmask]
Website: http://www.ems-consulting.com

----- Original Message -----
From: Jim Gilbert <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, June 09, 2000 9:03 AM
Subject: [TN] Solder Fill


> Technetters,
>
> We have a customer that is touching up the assembly after wave solder.
>  This touch up is to improve the aesthetics on holes which have not
> completely wicked up on the lead.  We have explained to him that this
isn't
> necessary and he is probably doing more damage than good, however this
> isn't the issue.  The issue is that when he pulls the soldering iron away
> from the hole the solder appears to fall through the hole and wick on the
> component lead on the opposite side.  We have done cross sectional
analysis
> to ensure the holes aren't voided and the solder isn't being pulled in.
>  Sections look good with a consistent ounce of plating in the holes.  I am
> unsure of what the hole sizes are that he's having problems with, but
> obviously something is awry with the solder "falling out".  Any ideas on
> what cause may be?
>
> Thanks in advance for your help.
>
> Jim Gilbert
> Electronic Circuits & Design
> Sebring, Ohio
>
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