At  3:21 PM 9/8/97 -0500, Erik Olson wrote:
>Hi TechNetters,
>
>I'm planning an experiment to test adhesive screen printing used to attach
>bottomside components to a PCB.  My first thought for how to test this is to
>measure the strength of the adhesive bond between the board and the
>components.  Is anyone out there familiar with the equipment and steps
>required to perform what I've heard referred to as a "pull test"?  And, are
>there any other variables/parameters that are useful to measure in a test of
>adhesive screen printing?
>
>Erik Olson
>Manufacturing Engineer
>Westell, Inc.
Erik
        Pull testing works and we've done our share of it, but we've found
that die shear testing is more indicative of performance of adhesives for
chip attach.  It more closely resembles the forces the parts see in actual
use.  We use a tester by Dage (not intended as an endorsement, but we make
good use of the machine).
        Howard Feldmesser
        The Johns Hopkins University Applied Physics Laboratory