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I'm trying to place some 100W wire wound resistors on my board and I'm going to be using my ground plane and some vias as my heat sink. I have a polygon labelled "GND" on both sides enclosed by a stop mask so the copper will be exposed. There is also a GND polygon filling the entire board on both sides, not just near the resistors.

Most of my vias connected to the ground plane without issue but a bunch of them won't connect and I'm unsure why. You can see the airwires in the screenshot below.

I've seen a few other people have issues getting things to connect to the ground plane but the solution usually had something to do with a specific package.

All of these vias are right next to each other on top of the ground plane with no traces between so I'm not sure why only a few won't connect.

Any thoughts?

Screenshot of my vias

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  • \$\begingroup\$ Ideally I'd like to get rid of these errors just for my own sanity. But a broader question would be, does it even matter in this case? These are supposed to be thermal vias, there shouldn't be any current running through them. Would I be able to get away with ignoring these errors in this case, or would that cause other issues for me later? \$\endgroup\$
    – Avid Pro Tool
    May 29, 2018 at 21:12

1 Answer 1

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Use RATSNEST to update the polygon.
Use the NAME tool on the via to assign the net GND to it.

Fresh vias don't inherit the polygon net. Copied vias do keep their net.

Once the via net is set, it cannot be changed with the NAME tool again.

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  • \$\begingroup\$ Hello, thanks for your response. I have already made sure all the vias are named "GND" and assigned to the same net. Ratsnest still isn't having any effect on these. This is only happening to 79 out of the 1000+ vias I have here and many of the problematic ones seem to be near my holes for mounting the resistors. Any other ideas, I'm sort of lost here? \$\endgroup\$
    – Avid Pro Tool
    May 29, 2018 at 20:08
  • \$\begingroup\$ @StefanRichter do you get any errors about overlapping drills from the DRC? You may have some vias on top of others. The other thing is to try naming the air wire, make sure it is the correct name. \$\endgroup\$
    – Tom Carpenter
    May 29, 2018 at 20:21
  • \$\begingroup\$ Nope, the only errors I get from DRC are the airwires, and they do appear to be named "GND" as expected. \$\endgroup\$
    – Avid Pro Tool
    May 29, 2018 at 21:09
  • \$\begingroup\$ @StefanRichter did you turn on all layers during DRC? \$\endgroup\$
    – Jeroen3
    May 30, 2018 at 5:44
  • \$\begingroup\$ @Jeroen3 yes sir \$\endgroup\$
    – Avid Pro Tool
    May 30, 2018 at 5:59

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