I want my plane to go to the edge of the board but still have clearance on the pads.
I can’t work out how to do that! I found a clearance setting but it affects both pads and board outline.
Unfortunately that’s not possible yet. It is planned for LibrePCB 2.0:
May I ask for your use-case? Plated board edge or just a smaller clearance to the board edge?
Maybe as a workaround you could add a trace (on the same net) around the board edge to fill the plane clearance with copper, but I didn’t try it.
It’s actually not that important to me right now. I was re-creating a board in librePCB that I had made in other software years ago, and on the original the ground plane went to the edges.
One likely use case would be when a plane is used for shielding and you want it to contact a metal chassis. So in that case you’d want a clearance for the solder mask but not for the plane itself.
JLCPCB has always made my boards with planes to the edge of the board without complaining about it - so I had not heard of some manufacturers not allowing this. Seems to me, if they don’t etch the copper away then it will go to the edge of the board, a clearance is actually not the default manufacturing situation.
All that said, it’s not actually important to me right now, I was just a bit surprised that LibrePCB couldn’t do it!
Ok great, thanks for clarifying.
Just be careful with copper going to the board edges. Even if manufacturers don’t complain, they might remove a bit of copper because they don’t like to cut with the milling tool into copper. That’s really bad as it can make a board non-functional if a thin copper bridge was there in the design but is then removed by the manufacturer.
ah good to know thanks! I never put circuit critical stuff near the edge of the board though. My boards that have copper to the edge the copper is recessed just the tiniest bit, barely visible but I assumed that was an artifact of the cutter.
I will probably start just using the clearance now the reasoning is explained to me. It might be nice to be able to set the clearance differently for outline, pads and maybe other sorts of objects.
Yeah, that’s basically the idea of the GitHub issue mentioned above.