Hoping someone can give me some help please. I’m trying to create a custom annular ring which will be used as a thermal ring on a simple LED board which will also have some mounting holes in.
I can create the ring OK using the Custom Shapes “Ctrl + E” and adding a plain circle and adding it to the F.Cu layer. But when I add the holes the DRC doesn’t like it and get ‘Items shorting two nets’ error.
I believe this error to be because there is no boundary generated in the F.Cu circle layer. I’m relatively new to KiCAD (coming from Eagle) and I’m not sure how to resolve this.
I’ve attached the footprint. Can anyone help please?
I loaded your footprint in the footprint editor, and it looks plausable, although I do not know what the big 32mm ring does exactly.
At the moment it is not clear what your problem is, can you make an example project with a (simple) PCB that clearly shows your problem? (and the exact text of your error message)
The pad creates a thermal ring for mounting against some metal work to act as a heatsink. The LED is on the opposite side and the top layer is flooded with vias coming through to connect to that ring. That works OK and without errors.
Using the footprint checker I get the following errors and these pass through to clearance errors to the DRC of the final PCB.
I can create a simple project but for now please see below for some images which should hopefully help explain
P.S, don’t worry about that 3-way PCB header at the moment. I haven’t chosen the final one yet
I don’t know the exact footprints rules but for me surprising is to have NPTH holes at SMD pad.
Thermal pads in for example QFN footprints are done with SMD pad and many Through-hole pads on it.
If you place NPTH hole at SMD pad and KiCad don’t use zone fill algorithms to fill that SMD pad shape (I think) then there is no way for KiCad to create a needed clearance between copper in your pad and NPTH hole.
I don’t know if it is still (V7) valid but some time ago (V5) I read that NPTH holes have to have pad size being equal hole size.
If the ring is already full with via’s, then some extra copper don’t hurt. Your problems seem to originate from the NTPH holes. In this modified footprint I changed the NPTH pads to THT pads, and gave them pad number “1”, just as the ring itself.
