I recall from my early intro into SMT that solder balls are caused by the
rapid melting of the SMT paste during reflow. It is a violent transformation
that literally causes the solder paste to explode as it becomes a liquid,
causing a splattering of molten solder.

The way around that was to do a careful preheat for a certain temperature &
time ( the 2 of which I don't know - only a reflow technician would have the
historical & empirical history to tailor these as they change with different
pastes, etc. ). This causes the extra liquid resins in the paste to
evaporate & thus result in a more subdued reflow process, eliminating the
splattering of molten solder which, when solidyfing, results in "Solder
Balls".

Am I somewhat on track here or way off ???

This intro was well over 10+ years ago.

Regards
TDK



-----Original Message-----
From: Steve Gregory [mailto:[log in to unmask]]
Sent: Thursday, July 22, 2004 8:10 AM
To: [log in to unmask]
Subject: Re: [TN] My solderball saga...

Hi Ramon!

You did see the pictures of my solderballs didn't you? If not, look at:

http://www.stevezeva.homestead.com/files/AdapterSolderballs.jpg
http://www.stevezeva.homestead.com/files/AdapterSolderBalls2.jpg

and tell me how you're going to use a soldering iron and wick to get at
these
solderballs to remove them? These adapters were used 6-per assembly. We're
using the DIP IC now that these adapters were being temporarily subsituted
for...

-Steve Gregory-


> I would be very concern about how to get rid of solder balls, specially if
> they are small. My method to remove them with be with a solder iron or
solder
> iron, solder wick combination. Blowing them off may impel them in between
> solder balls under a BGA or between leads and cause shorts. That would be
very
> bad.
>     Just a thought
>     Ramon
>


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