alright, mr. lomax... i seen that comment about making a
brick.  hahaha.  this board is a wraparound selftest for
an interface device.  it plugs in where the device under
test (dut) would and checks copper path.  the dut does 
indeed have two 63mil boards adhered onto a metal core.

we have purchased a test program set for a similar (different
connector) dut and the delivered wraparound card is a full
330mils thick.  other than the connector, which are surface
pads, there are NO components on the board.  i am attempting
to make it so that there are no vias, either, wrapping each
side independently.  so we are talking no power planes, very
low speed (essentially static) wraps from pin to pin.  power
lines will be verified by wrapping to a digital pin and testing
the voltage level.  i do wish to put a probeable thruhole pad 
for each wrap, just for visibility and a sanity check on my
selftest software.

if i have no choice, then i will use a core and two thinner
boards, but it amounts to buying 3 parts instead of one and
having additional assembly processes that would be somewhat
critical...  the connector is a pre-assembled double-sided 
surface pad (pins on bottom and top layer) affair with 150 pins
per side with 50mil pitch.  alignment would be important. 

thanks, miker

You have just made my day. I would be very interested in the reason why you
need the material so thick. How many layers? Tolerance on layers?  Type of
technology used ( I would assume all SMT). Any strip line?  Buried vias?
Any special material requirements?  How do you plan to solder the boards.
A few suggestions.  Hand solder the first boards.  Something this thick will
be hard to profile.  Start with full-flow pre-preg.  If your board is SMT,
don't allow any vias under the components.  The pre-preg will tend to
extrude out of them making a dimple.  If you try a fill material, double
check that the thermal expansion coefficients match the board material. Can
you explain the application?  There may be a better way.

Please send all responses to the following address:


Version: PGPfreeware 7.0.3 for non-commercial use <http://www.pgp.com>


----- Original Message -----
From: "Robison Michael R CNIN" <[EMAIL PROTECTED]>
Sent: Thursday, December 20, 2001 9:03 AM
Subject: [PEDA] special board requirements ??

> hello,
> the board shop that i've been using has been doing an excellent job for
> me, but i've got a board now that they can't do.  its extra fat and it
> some milling done on it.  can anyone recommend a shop that will do it
> for me?
> i need a 330mil thick board with 70mil taken off of mirrored sections on
> both sides.  i'm thinking a 100mil radius tolerance on the inside of the
> milled corners, and probably +/- 5 or 10 mil on the milled edges.  the
> size of the board is 12"x7".
> and merry christmas and happy holidays to everybody!
> thank you, miker

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