Thanks for the help.


______________________________ Reply Separator _________________________________
Subject: Re: Solder paste kneeding
Author:  [log in to unmask] at Internet
Date:    10/2/96 4:16 PM


Vigourous stirring of  paste will cause its viscosity to fall. (Sheer thinning) 
If your paste works after treatment like this, but not before, it suggests that 
the start/supplied viscosity is too high. 
I assume you are not trying to use paste taken straight from the refrigerator 
(cold paste is thicker than warm paste) so
Maybe you are using a formulation which was correct when frst determined a while
ago but has not followed changes in your work . 
Alternatively some paste suppliers do supply pastes with high initial 
viscosities which are intended to be sheer thinned on/by the printer into a 
usable viscosity range in continuing production.  If this is so try using a more
appropriate product.
As a start suggest you check your supplier data sheet recomendations and compare
to what you are actually doing and using, then speak to your supplier . 
Caution: This would be a break from standard  industry practise: most people 
don't read anything before beating up on their supplier.
     
     
Mike Fenner
BSP
----------------------------------------------------------- 
Paul Stolar  wrote
     
     Does anyone else have the problem with their no-clean solder paste 
     needing about 20 kneeds to get the proper volume? If so, are there 
     other ways to get there quicker?
     
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