Hi Nick.   You should find that many of the ICT fixturing houses are
     more than capable of producing acceptable vacuum fixtures with top
     side probing without resorting to hydraulics.  I do have both, but the
     hydraulic ones are for non-standard interfaces (read as: no vacuum
     available)

     If you have a vendor telling you that you need to use hydraulics on
     your fixtures, I'd love to know their reasoning (other than making
     some extra bucks)

     ----

     A thought for you: trot out your DFT homework!

     - Topside probing has less accuracy. Make your test pads large with a
     nice surface to hit.

     - Give yourself lots of component-to-pad spacing, especially around
     large components

     - Don't use device pads as test points if a device is mounted there
     also.

     - Expect your fixturing costs to be substantially higher.


     Hope this is helpful -

     -------------------------------------------------------------
     Robert D. Green - Supervisor, Test Engineering
     Hadco - Value Added Manufacturing
     e-mail [log in to unmask]



______________________________ Reply Separator _________________________________
Subject: [TN] Component Side Test Points
Author:  Nick Nicolaides <[log in to unmask]> at smtplink-hadco
Date:    5/11/99 8:26 AM


We are in the process of evaluating using top (component side) test points
in addition to the solder side. We know this will be a major change in our
test fixtures, that is going to a clam shell. Also what is your experience
for the ICT: vacuum vs. hydraulics?

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