I am sending off a pcb for manufactering, but it would be nice to round off the corners for them to mill off.
How can I make nice rounded corners? I have used the three point arc thing before but I dont really like that…
In what layer should I specify what should be milled off?
I'm also intrested in how to specify a small rectangle (ca 20 x 10 mm) to be milled in the middle of the card?
In Eagle, the "Dimension" layer represents the perimeter of your board. You can create a new board perimeter by drawing an enclosed shape using the WIRE command to draw a new enclosed polygon. When you draw your lines, you have the option of changing the wire bend to go straight and then arc (option 6 and 7). I used a width of 0 for the shape.
When you go to export the design, you can export the outline separately or on a existing layer. For example, BatchPCB suggests adding the outline to the silkscreen layer, or having a separate outline gerber.
I'll second Kellenjb's comment that not all board houses are thrilled at the idea of arbitrary board shapes, so you may pay extra for the rounding.