Good day!

    First I would like to express my thanks for the inputs I have received 
in response to several of my requests in the past. They have all been very 
helpful in resolving the issues that I needed help on, or when I needed 
"another voice" to echo my position on certain issues. I think we all get 
busy and sometimes neglect to acknowledge the efforts of others.

So now that I've finished "kissing-up"...<GRIN ;^D> I'm wondering if I 
could solicit for some more opinions....It has to do with stencil set-up.
We're refining and detailing our ISO 3rd-level procedure for the Screen 
Printer. A few of us seem to be at "loggerheads" on the issue of stencil 
"Snap-off".....

* One side says that when dealing with "fine pitch", using snap-off is the 
  best way to ensure that you'll get enough paste through the stencil and 
  on to the PCB.....

* The other side feels that snap-off is a hold-over from the days of    
  printing solder paste through a screen, and also used to "band-aid" a 
  problem with the design and/or the workmanship of the stencil...that as 
  long as the apertures are designed within the guidelines for aspect 
  ratio of 1.5-2 times the thickness, sidewall quality is good, and the    
  correct mesh paste is being used, there should be no reason at all for 
  "snap-off".....

We want to write the kind of 3rd-level procedures that spell out possible 
problems that could be encountered during production, so that operators 
will "raise the flag" when they run across situations that may have an 
affect on the yield of the process, rather than trying to "make something 
work" when it isn't right to begin with.....

                                         Thanks in advance!!

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        Steve Gregory       

  
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