Another option is to determine whether the surfactant in the flux is needed for 
thermal transfer or not. Eliminating this surfactant will reduce the amount that
can be left on the board.

 Determine which detergent type can be used to best clean the panels before the 
post clean rinse. Install a detergent applicator there.

 The cleaner the water the better.

______________________________ Reply Separator _________________________________
Subject: RE: HASL Post Cleaning
Author:  JMONAGHAN at hadcoderry
Date:    3/19/96 4:57 PM


Hi Lou,
     
     
Sounds like you have quite a complicated post cleaning process. 
You don't say what kind of through-put you have so I am assuming 
you run small to medium volume panel counts.
     
We had used Dexter 1885 flux for about 2 years (currently using 
Dexter 1807.)  I believe your best alternative to what you are now 
doing would be to purchase a conveyorized post-clean machine.  We 
are using an Argus machine which consists of:
     
1.  A bank of fans to cool the panels before entering the first    
    scrubbing chamber.
2.  First cold water spray and scrub chamber.
3.  Second cold water spray and scrub chamber (water cascades into 
    the first chamber.)
4.  Final cold water rinse.
5.  IR dry chamber.
     
Note:  All water is city water, no DI.
     
We typically see ionic resistivity readings after post clean in 
the range of < 1.5 micro grams/sq. cm. NaCl.
     
If you do prototype volumes, I might have some other suggestions 
as we used to have a Lightning machine with a different post-clean 
system.  (Those were NOT the good old days!)
     
Good Luck
     
Dave Rosato
SAE Circuits Colorado
(303)530-1900
     
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