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1996

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From:
"ddhillma" <[log in to unmask]>
Date:
Fri, 07 Jun 96 08:20:12 cst
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     Greg/Norm - 
     
     Just a thought but how about doing a very light UV Ozone cleaning 
     process to your plastic parts to remove contaminates? That should get 
     rid of contaminates and not destroy the plastic part body if properly 
     controlled. We use UV Ozone cleaning prior to a COB process with 
     organic substrates with good success at removing contaminates on the 
     substrate surfaces. I suspect that there are UV Ozone cleaning systems 
     that could handle large quantities of parts too. Try contacting 
     Jelight Company, Mark Mijat,714-380-8774 or Samco International, Dan 
     Abercrombie, 408-734-0459 for info on UV Ozone cleaners.
     
     
     
     Dave Hillman
     Rockwell Collins
     [log in to unmask]
     


______________________________ Reply Separator _________________________________
Subject: Re: ASSY- Laser Ash?
Author:  [log in to unmask] at ccmgw1
Date:    6/6/96 4:20 PM


                      RE>ASSY: Laser Ash?                          6/6/96
     
Funny that you should mention this, Norm.  I believe that we're seeing a = 
related problem.  While we're not seeing a white residue, we are seeing a = 
problem with laser etched devices.  We use thermally-screened devices on = 
certain products.  Our screening house uses a yellow epoxy dot on the = 
corner of the device to signify successful screening, but these dots have = 
been falling off of the laser etched parts.  We suspect that the laser is = 
modifying the surface of the devices somehow (redeposition of carbon, perha= 
ps?) to cause this.  
     
Any thoughts on how to either clean the device surface or come up with an = 
alternative, inexpensive way to mark these devices?
     
Greg Bartlett
Mercury Computer Systems
Chelmsford, MA
[log in to unmask]
     
-------------------------------------- 
From: Dill, Norm J
     
     After cleaning (soap & water) soldered assemblies, has anyone had a 
white residue problem that was traced back to the laser etched characters = 
on 
plastic DIP's?
     We currently have a white residue problem under investigation where =
the 
initial evidence indicates the source to be a certain brand of DIP IC.  = 
The 
top of the DIP has laser etched character markings that appear to leach a 
chemical component(s) that combines with the rinse (tap) water to form a 
white residue after drying.  The residue is easily removed with a cotton 
swab and alcohol.
      At this point the complaint is only visual and easily corrected by 
hand cleaning but the concerns are what is actually being deposited on the =
     
board surface and is it being completely removed.
      Any inputs on this will be greatly appreciated.
     
     Norm Dill
     Harris RF Communications
     [log in to unmask]
     
     



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