1)  Has the question posed by Tom Olafsson below ever been answered?  I
could not find any follow up in the archive.

2)  Has anyone published a report on SMT solderballing, such as causes and
cures?  I have seen a lot of correspondence on the wavesolder generated
solderballs, but I am looking for a cure to what we call "squeezeballs"
(usually found on the sides of 1206 chip caps and resistors.  We are about
to initiate a DOE to solve the problem by varying the solderpaste print
shapes (home plate shapes, etc), stencil thickness, as well as three other
parameters.

3)  How is the J-STD-001 defect for solderballs supposed to be
interpreted........anotherwards if the solderball is encapsulated and
doesn't reduce the minimum design electrical clearance, can it be larger
than .005"?

4)  We have run a no clean process for five years without ever having a
failure related to solderballs, but we have been asked to eliminate
solderballs entirely.  Is this too much to ask from a no clean process?

5)  Does anyone have a good method for removing solderballs from the sides
of chip caps without running the risk of losing it under some other
component?  Use of a vacuum desoldering device has been suggested but the
tips aren't small enough to reach in between a lot of the components.


All suggestions or responses will be appreciated.

Regards,


Phillip A. Bavaro
Senior Manufacturing Engineer
[log in to unmask]
(619) 658-2542

_______________________________




At 5:51 PM -0000 10/16/96, [log in to unmask] wrote:
>Do any of you know of or have a checklist (at a high level) of what should
>be investigated if solder balls left on PCB assemblies after reflow?  What
>is typically the most common cause that should be investigated first?
>
>Thanks,
>
>Tom Olafsson
>Teradyne Inc.
>[log in to unmask]
>
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