I hereby certify that I am not simply asking someone else to design a footprint for me.
This is an auto-generated message that is in place on the “footprints” section of the KiCad.info forum. If I remove it and ask for a footprint to be designed anyway, I understand that I will be subject to forum members telling me to go design my own footprint or referring me to a 3rd party footprint site.
Hello all. first post, but I’ve used KiCAD for a long while. I have a tricky footprint that I can’t work out an approach for. It sounds simple but I can’t work it out! I need a footprint that looks like a large circular through hole pad but isn’t! I need a 7mm diameter pad on the front and a matching pad on the back copper layers with top pad being 1 and bottom pad being 2. There needs to be no through hole plating so they are separate and there needs to be a hole 4.8mm in diameter in the middle for a pem nut insert. I can make an SMD pad top and bottom but if I put a edge cut hole through the centre of them then I can’t connect to the pads when using the footprint of course. I’ve read some stuff from making pads from shapes but I can’t seem to work that out in vers 7. I can get the look correct with a pair NPTH mechanical holes, but of course I can’t number the pads to connect them to anything! I can’t work it out… all clues greatly appreciated! I’m using v7 on Ubuntu 22.04.
Sorry, I think I’ve found a solution now using large SMD pads in the footprint and using an edge cut to put the hole in in the board layout level. Admin please delete this post!
It is surprisingly difficult to do this “properly” (as far as I know). You could absolutely take one of the standard mounting hole footprints and change out the throughhole for a non-plated throughhole or edge cut and it probably would be fine. However, you’d be drilling a big hole through copper and that increases the risk of shorts between layers if you aren’t careful. Since the pads on top and bottom are regular SMD pads, you can’t have them automatically pull back from the hole edge like a zone would.
The best way I’ve found to do this is to make a fake concentric circle out of two sets of arcs. Image below shows how I would do it in KiCad.
I think I’ve worked out a solution using smd pads in the footprint and edgecutting the hole in the board layer, but it’s deffo a kludge! I agree, it’s hard to do this in a way that feels correct!
It doesn’t make sense to delete posts if someone describes a problem and somebody gives a solution. It doesn’t matter at all if they two are the same person.
I did something like this with ring shaped pads on top and bottom (using custom shape primitive) and edge cut hole in the center. I needed a hole larger than the maximum drill size anyway.
This is essentially what I’m doing as a kludge, big circular SMD pad aligned each side in the footprint and then in the board layer adding the hole as an edge cut.
Thats a great solution. I was just chatting with a fab and they didn’t like the idea of copper being under an edge cut so I think adding a ring as a custom shape primitive and hiding a small anchor pad in the ring is the best option. Thanks for posting this.
