I created a polygon that I intend to use as a heatsink. The problem is that there is a lot of clearance at the edge of the board, much more than around traces even, why is that? How can I set board clearance independent of isolation setting of the polygon?
Like many settings in Eagle, the setting is there, but it's not in an obvious place where you would look for it. The copper to board edge clearance is burred in the DRC rules.
- Select menu
Tools -> Drc...The DRC dialog will open.
- Go to Distance tab.
- Change the field Copper/Dimension to the desired width.
(Be sure to consult the edge clearance specifications set forth by the PCB fab.)
Applythen close the DRC dialog.
- Click rat's nest to repour the polygon pours.
(These screeshots were taken with Eagle 6.3.0.)