Re: gEDA-user: Clearing mask to mount shields

[Karel Kulhavy <clock@xxxxxxxxxxxxx>]

On Fri, May 05, 2006 at 12:16:56PM -0400, Dan McMahill wrote:
> Darrell Harmon wrote:
> >What is a good way to expose a ground plane for mounting a shield?
> >I have a board which needs to be very well shielded, and am planning
> >on making a machined aluminum plate with compartments for each 
> >section of the circuit. The board will screw to this instead of
> >standoffs. What is a good way to clear the soldermask in strips so
> >that the aluminum can be in contact with the copper?
> >
> >PCB won't let me convert a polygon to an element. It will not allow
> >traces wider than 250 mils, so creating the pattern with traces is 
> >not a good option. Is there any way to use one of the spare layers
> >as a mask keepout layer? The only way I see right now to make it 
> >work is to create several traces side by side in the larger areas.
> >
> 
> Can you create a footprint with some pads that are the right 
> width/length for the shield?  That way if you move the shield around on 
> the board you'll keep all the pieces together.
> 
> Don't forget, its the largest dimension of a gap, not the area which 
> matters the most.  So if it is a 2 layer board with ground on the 
> bottom, components on top and a can attached to the top, you'll want 
> lots of vias around the edge where the can sits.

I have a via every 200mil - is it OK? Or should I make it every 100 or
50 mils?

CL<