Guenter,
I'm not quite sure I know what you mean when you say "There is no test for
the mechanical properties of a solder joint of a component."  I have in my
hot little hands (well actually cold big hands, its -19C here this morning)
a copy of IPC-SM-785 "Guidelines for Accelerated Reliability Testing of
Surface Mount Attachments".  Werner and friends have put this together and
surely this type of testing gives an indication of the sum total of the
mechanical properties of solder joints, doesn't it?  There are a few other
"tests" that come to my mind as well.  They include: plain old visual
inspection (is there a good heel fillet?), solder pot analysis (if you have
concerns about the PTH joints) and finally pull and shear testing.  Now
before the reliability gurus start lashing me with flex cables (worse if
components are on them!) let me say that this is a test of the "now"
strength of the joints and is not necessarily a measure of the long term
reliability of a solder joint.  It sure gives you a measure of  possible
infant mortality failures due to solder joint weakness, though.

Bev Christian
Nortel
Belleville, Ontario
CANADA

> -----Original Message-----
> From: Guenter Grossmann [SMTP:[log in to unmask]]
> Sent: Wednesday, January 06, 1999 11:11 AM
> To:   [log in to unmask]
> Subject:      Re: [TN] SOIC solder joint integrity
>
> Jerry
>
> There is no test for the mechanical properties of a solder joint of a
> component. Looking on the many tests I made so far I think that
> microsections are still the best method to evaluate the integrity of a
> solder joint. Maybe, an X-ray ahead gives some clues about void formation.
> If the microsection shows the intermetallic layers and no cracks then the
> mechanical properties of the joint are given since the soldering process
> and consequently the alloy formation took place.
>
> Best regards
>
> Guenter
>
>
>
>
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