Hi,
I’m designing a board, it is M.2 format, 22x60. The problem is the hole for the screw, it is like a pad cut in half but I don’t know how to do it in Kicad. Now I just have a normal pad but the board outline (edge cuts layer) crosses it so I get a DRC error.
180 degrees of arc in the edge-cuts layer?
If I do an arc I still have to cross the pad to draw the arc on the inner cercle of the pad so that the half annular ring is inside the board.
But I searched the forum and I’m not the only one with this problem it is about castellated holes, following what I read I just have to ignore the DRC violation and tell the manufacturer that the pad is for castellated hole.
You did not mention Castellation.
As far as I know, this FAQ is still current:
https://forum.kicad.info/t/castellated-edge-plated-half-holes-in-board-edge/23969/1
Remember that castellated hole means it’s plated through. It’s pretty expensive in small batches. You don’t necessarily need plating for mounting holes. It would then be a normal routed edge and you would save money. But in that case the copper should not touch the edge or you should communicate your intention to the manufacturer.
There is only one half hole, so it should not cost much.
Yes I don’t need the hole to be plated, I just need the top and bottom layer for the screw. You said the copper should not touch the edge. So, I make a 180 degree arc in the edge cut layer so that it contours the outer circle of the mounting hole ? But the mounting hole will be like outside the edge cut zone so there will be no mounting hole on the PCB.
I drew an arc on the front copper. I then drew an arc on the bottom copper, then hotkey E to Arc Properties and edited the width of the arc.
Would this technique be suitable?
The (two) cheap Chinese manufacturers don’t count, the price just jumps up if some special technique is needed.
It cost them the same to do one hole or many.
It’s an extra step in the process. And it does all the hole on the same edge. They are dipping the side of the board in a bath. So thay have to do it for each edge of the board.
it could be an option to add two SMD pads F.Cu, B.Cu and an edge cut arc…
check only the pad for the drill, the fp comes from a mSATA disk
M2-mpcie-full-minimal.kicad_pcb (9.3 KB)
It shouldn’t add any extra cost
Yeah, I did an M.2 and started going down this path about a semi-circular copper bit – because that’s what others have done, right? Then I thought: the standoff in the main board is grounded, so why do I need the screw grounded on the daughterboard? And don’t need the mechanical strength. So I just left it bare pcb and used a little arc on the margin layer to keep the ground plane fill from intruding.
You can also look at how sparkfun did it (grab the eagle files from their github and import).
Are you planning to use the screw as a means to keep the SD card from falling out?
Sure, for prototypes, the special technique usually charge separately. I do not know whether two Chinese manufacturers will charge for it.
I think you can just put an arc on the edge cuts layer and all will be good. But true, there will not be a “mounting hole” part in your design using this approach.
Since you do not need that hole be plated, it will be NPTH, you do not need pay extra cost.
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