I've seen occasional submissions asking about rivets for holding
multilayer boards together in the lamination press.  Would someone fill
me in on what's involved there?

   What is the purpose of the rivets?  To constrain movement in the press?
Can anyone quantify the benefit?  What kind of tolerances are achieved?
Are they aimed at improving layer to layer alignment within a panel, or
affecting whole panel movement?  Sideways shifting (translation/rotation)
or inch per inch movement (shrinkage)?

   Are they used in addition to pins?  Are they ever removed?  What forms
the composite locating system (for drilling, etc.) if not molded slots?
How and when are the holes for the rivets put in the cores?

   Are rivets only useful in a certain pressure range?  My impression was that
cores will do what they want to do in the press and just deform against
anything you try to put in their way to restrain them.  Do you need to keep
the pressure low to prevent this?

   What kind of products are rivets used on?  Fine line, thin core, tight
tolerance stuff or coarse, thick core, easy stuff?

   Thanks,

 Jonathan Whitcomb

 IBM Microelectronics

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