Jens,

The answer to your question is it depends.  It depends on several factors:
Basically the press package must have the proper rate of rise through
the gel window.  These temperatures and rates will change depending on the
type of laminate you are pressing.  Assuming you are using FR4.  10 - 12
'F/min
is a typical rate of rise, required from the 180'F to about 240'F. Your
material supplier
will be able to give you more information.

Also the how many layers are the boards? Are you vacuum pressing or
conventional
pressing?  What psi are you pressing at?  How many panels are you currently
pressing and how is their quality?  What is the finished thickness of the
boards?

If the boards are .062" and you use steel seperators you may be able to
press 7 to
8 panels at a time.  I would not try to exceed press pins longer the 1.5".
However
the quality of the cycle will limit you stack height.  You might want to
try aluminum
seperators to increase you stack height to 10 -12 panels.  However,  I will
warn you
that the cycle must be checked for rate of rise to guarentee good product.


The time of the cycle (assuming FR4) will be the time it takes to achieve a
temperature 325'F at the center of the book + 45 to 60 minute cure time
under full pressure + 25 to 30 minute cool down cycle.  If you are using
vacuum add on 15 minutes for a vacuum dwell at the beginning of the cycle
to remove air and solvents from the package.

There is alot more to pressing then just this,  I would suggest having you
material vendor come in to help set up cycles for maximizing your press
capacity.  After all
it is their material, let them work for the money.  Yep!

John Haman Jr.
American Board Companies



----------
> From: JB <[log in to unmask]>
> To: [log in to unmask]
> Subject: [TN] Multilayer press - simple question....
> Date: Wednesday, April 08, 1998 5:27 AM
>
> Hi all,
>
> please excuse my complete ignorance of the multilayer press process. I
have
> some (probably) very simple questions:
>
> 1. How many panels you can press in one opening? (presume panel size =
> steel sheet size)
> 2. How long does the whole process take?
>
>
> Best regards
>
> jens Behrens
>
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