Hi,

Recycle solder paste. We use Kester and asked our vendor the same question.
They supply us buckets and give us so much per pound for the water paste.
On a technical data sheet it should give you a screen life on how long
solder paste should last open to the air. Norm could be 8 hours max. We are
running MPM 3000's and looking into the rehometric pump heads. Currently
MPM took our paste and today after testing told us. That the paste which we
are using is the best tested so far. Where after kneading the paste 8 times
they ran 100 PCB's fine after the same paste sat in their head for 7 days.
So looks like we are going to get one retro to start with and if it works
as planned then do the other 3 lines.

Have a good week

At 05:46 PM 1/19/99 , you wrote:
>Ladies & Gentlemen:
>
>     We are currently experiencing a problem in our MPM printing process.
>Often, the solder paste gets dry and leads to product defects.  As a
>result, operators dispose the "dry" solder paste.  However, the measure of
>"dryness" is very subjective and varies from one operator to another.
>Consequently, our facility is disposing too much solder paste.  Is anybody
>measuring the "dryness" of solder paste?  If so, how are you doing this?  I
>need a scientific way to determine solder paste dryness, and a guide that
>will let me know when the solder paste is no longer good.  In addition, is
>there any way to "recycle" dry solder paste?  Are there any solvents or
>chemicals that will restore the solder paste to its original condition?
>
>     The solder paste is currently being placed by hand on the stencil.
>Before the stencils are washed, the solder paste is removed and placed back
>into the jar.  This results in cross contamination of new and used paste.
>To resolve this cross contamination, we would like to use an automatic
>catridge dispenser which is available with MPM printers.  Is anybody using
>these automatic dispensers? If so, do you have any "lessons learned" or
>"recommendations" for using this new equipment?
>
>-Thanks for your help,
>
>Teo Tijerina
>Conexant Systems, Inc.
>
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