Happy Holidays Ya'll,

I'm about to order my first stencil directly (rather than thru CEM),  
but have a few Q's, which I've not been able to get properly answered  
from a couple stencil companies.

(1) Since a copper layer specifies pads and traces on that layer, how  
do they determine what is a pad, vs. what is a trace?  Is there  
something in the specification of the gerber that tells them that  
(I've found some basic gerber-format explanations so far, but nothing  
yet that tells me how a trace is specified different from a pad)?  Or  
is it that pads are copper without soldermask?  Or???

(2) Are the stencil holes always the exact size as the pads, or is  
there some border that's left, making the stencil holes a bit smaller?

(3) I need to add four 0.125" holes on the stencil to match holes on  
my PCB.  I'll use these to easily align the stencil, by using four  
0.125" dowels.  How can I best specify this on the PCB.  If I create a  
library part that is a 0.125" circle and add these to the appropriate  
locations on the PCB, will I get these as 0.125" holes on the PCB, or  
will they be a bit smaller, or...?

(4) Is there a simple way to temporarily block holes on a stencil (for  
various configurations etc of a PCB)?

Cheers,
-Neil.




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