I am trying to make footprints for feedthrough bulkhead connectors with “D” or “double D” holes surrounded by a circle of unmasked copper that connects to a filled zone of the GROUND net for grounding the connector shells; the circle is large enough to fit the outside diameter of the shell and nut. I’ve attached a picture showing the idea – the inner shape is a cutout on the Edge.Cuts layer, with the circle being the area of copper that should be unmasked.
I’ve tried to create this a couple of ways, but am drawing a blank.
I tried using “Create Pad From Selected Shapes” drawing a circle and putting a pad in the center, but that seems to fail with a complaint that there are multiple shapes. If I position the pad to touch the circle, then I get a pad, but it’s just a ring the thickness of the circle line; I can’t figure out how to fill the interior of the circle.
I’ve tried just making a gigantic circular pad, and by all appearances that should work, but DRC shows it as unconnected to the ground pour and looking at the gerbers shows that the pad is isolated, even though it and the pour are on the same net. I think the Edges.Cut cutout has something to do with the problem, but I’m not sure.
I think that if I could find a way to fill the circle shape and put a pad inside it, things should work, but I can’t figure out how to fill a graphic circle in the footprint editor. Alternatively, making an arbitrarily shaped hole in a giant pad would work. But how to do either of those things eludes me.
I’ve never tried to make a footprint by the method you described. I suggest placing a circular pad with the dimension you want, then add the D or Double D cut.
Depending on size, the D might difficult to cut, particularly if it is small.
I’ll try that – I can see that the order of processing could make a difference in how things are interpreted.
Before I started this project, I sent the various cutouts to Seeed and they happily reported that there was no problem with them. I’m doing bulkhead feedthroughs for N, BNC, SMA, UHF, and F.
UPDATE: Well, maybe not. Recreating the footprint as described below seems to have worked once, but further attempts always result in DRC thinking the pads are not connected. But the Gerbers do seem to be correct, so maybe I just need to learn to live with the reported error.
This did it. I recreated the footprint with just the single giant circular pad (900 mils diameter) and then imported the cutout from DXF to the Edge.Cuts layer. That footprint connects to the net and the cutout comes through (confirmed by Gerber). You need to turn off layer visibility to tell, though because the solid surface of the copper and mask layers hide the Edge.Cuts layer.
After looking at the Gerbers, I think that the problem was with DRC and not the footprint per se: the copper layer shows no break, but DRC shows the pad as not connected.
Thanks for the hint!
