Hi Kevin , & ALL
To cut the esoteric pad area, gold slip layers calculations etc. short :
In practice when you actually get to do it, it's simple :
If you rip the pad off you're home , if you don't you have something to
worry about .
I did try small joints, BIG joints (PS) ; it applies reliably .
Therefore despite the theoretical complexity of all theoretical factors
( pad area, oxide-vetability, gold layers slip, plating, etc.) you CAN
make life easier on yourself just by making it a simple polarised
dilemma , which it in a fact is .
I started the same way before realised that for the trees I could not
see the forest .
So for the sheer adhesion by all means do establish the fact the pad
gave up , than you have a piece of mind ,
unless you need better than that . Than it's a different game
(substrate)
For High acceleration isothermal mechanical cycling , at elevated level
temperature ;
read for some hints page 7 , IPC-SM-785 , Guidelines for accelerated rel
. test ........ ,
the info is limited to stating what is it and that it exists somewhere
in the IPC files .
We need an IPC fellow to shed a light on this option of quick fix test
of limited but useful data acquisition .
I could be only guessing that it does consist of board flex cycling at ?
temperature .
There must be somebody who knows, otherwise it would not be noted in 785
.
See you
Paul (ResMed)
>----------
>From: Engelmaier[SMTP:[log in to unmask]]
>Sent: Saturday, 3 January 1998 1:10
>To: [log in to unmask]
>Subject: Re: [TN] pull test std
>
>Hi Kelvin,
>To my knowledge, there is no standard on pull testing leads or shear testing
>chip components, nor should or could there be. First, the high variability in
>pad/lead/component desig gives you too many variables; second, the pull/shear
>strength per se does not give you an indication of the solder joint
>reliability. Observation of the fracture surfaces can, however, give you
>information whether or not your solder joints are properly wetted.
>
>Werner Engelmaier
>Engelmaier Associates, L.C.
>Electronic Packaging, Interconnection and Reliability Consulting
>7 Jasmine Run
>Ormond Beach, FL 32174 USA
>Phone: 904-437-8747, Fax: 904-437-8737
>E-mail: [log in to unmask]
>
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