To:  [log in to unmask]      Attn: Designer Council Forum

From:   Mary Sugden             At: [log in to unmask]

Date:   August 20, 2001       Subj: "Capacitor Cracking"

Hello Again PCB Lovers,

Thanks to everyone who responded to the "Cracked Capacitor"
problem.  All of the suggestions provided a comprehensive
coverage of the problem.  I have passed on the responses
to the guy with the problem and he is very grateful.

The majority of responses pointed to damage caused by
normal handling stresses in manufacturing and installation.
Their appears to be two major contributors to the problem.

    1) Non-compliant leads
    2) Thinner boards

Over the years we have become spoiled by the toughness of
through hole assemblies.  Components with compliant leads
provide a mechanical stress relief against the board bending
and twisting that surface mount components do not.  The
simple force of pressing a board onto tooling pins for
automated processes such as component loading or testing,
could very well be cracking the capacitors.

Thinner boards lack rigidity and are much more susceptible
to the problem.  It might be a good idea to consider the use
of "stiffeners" to protect (rigidize) thin boards during the
assembly processes.  It might also be a good idea to make the
stiffeners permanent to provide on-going protection during
installation procedures and intended use.

Again thank you for your responses.  You are great!


Best Regards, Mary

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