Re: gEDA-user: pcb crooked traces

[Dave N6NZ <n6nz@xxxxxxxx>]

On Oct 8, 2010, at 10:27 AM, Dave N6NZ wrote:
> 
> I couldn't say what the standard panel sizes are in the industry, but I could make an effort to find out.

FWIW,

A quick poll of my friends indicates that 18x24 inches seems to be a standard panel size, but 48  x 22 inch boards used to be common in telecom, fabbed on 48 x 48 inch panels.  A friend at Cisco says they regularly do 16x26 inch backplanes now. (and 14x21 inch 14 layer (!) boards.... that's a lot of layers in 21 inches.  When I was at Amdahl, we did boards with 50 signal layers (and 12 or so power layers) but that was a smaller board, and we weren't trying to build thousands of them....)

Max size seems to vary a lot depending on the fab's equipment.

I think the fab house that did my 54 inch board in the 1980's used panels around 60 inches long.

So... if pcb were to be limited to a 2 meter by 2 meter board, would it actually be a painful limitation to anyone?  Now that I think of it, my 54 inch board had to be done in two pieces because of the CAD software...  but it was easy to line up the pieces because it was all transmission lines crossing the middle, and so vendor somehow got his photoplotter to paint left and right half files on the film with good registration.  I also had an adventurous tech working for me who enjoyed challenges...)

-dave


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