Tim,
        on your total thickness you seem to be forgetting the copper
thickness. Calculate copper thickness at 1.4mils(36microns)/1oz,
0.7mils(18microns)/0.5oz. The new stackup you refer to would have a total
thickness of 72mils (71.8mils precisely) using 1oz Cu weight.

Laminate:       (4x2) + (13.5x4) = 62mils (laminate alone comes out to
almost your 0.063")
Copper: (1.4 x 7) = 9.8mils
Total:  62 + 9.8 = 71.8mils


Brad Velander,
Lead PCB Designer,
Norsat International Inc.,
#300 - 4401 Still Creek Dr.,
Burnaby, B.C., V5C 6G9.
Tel. (604) 292-9089 direct
Fax (604) 292-9010
website www.norsat.com


> -----Original Message-----
> From: Tim Hutcheson [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, August 22, 2001 12:56 PM
> To: Protel EDA Forum
> Subject: Re: [PEDA] Warping on small odd layer boards.
> 
> 
> Brad, thanks.  Now I know how to count them.  :o)  And yes 
> the thinner layer
> thickness was wrong.  I just calculated that if I use
> 4,13.5,13.5,13.5,13.5,4 and can squeeze 8-mil traces onto the 
> two inner
> layers with 5-mil on the outer, everything should match up 
> for a .063 board
> with about 55 ohms per trace layer.  Does that make sense to you?
> 
> Tim Hutcheson
> Institute for Human and Machine Cognition
> 40 S. Alcaniz St.
> Pensacola, FL.  32503

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