Footprint with a board notch

(Disclaimer: I looked, but if this is a FAQ that I missed, please let me know :slight_smile: )

I am trying to use a Samtec ERM8 edge mount connector in a design. This connector is keyed on the board side and requires a notch in the board’s edge to correctly seat.

Screenshot from 2021-11-07 18-07-11 scale annotate

I’ve tried edge cuts in footprint (yeah, I know), edge cuts on the board, and all I ever end up with is this:


I’ve gone through the edge cuts in the board, “traced” the outline of this notch (by opening the board outline to make a gap and then using lines and arc to form the notch), checked that all edge cuts are snapped together correctly and not leaving gaps. Yet, I don’t get a notch.

What is the correct way to do this? Pointers, well-placed whacks to the head, all welcome.


How about “I have no idea”? I have not bothered with 3d since I used Autocad in DOS in 3d to design my electronic workbench about 25 years ago.

I had a popup issue and couldn’t download the footprint from Samtec.

But looking at the needed slot, doesn’t the slot need to go to the edge?

Maybe something like this:

If so I would just modify the board outline (aka edge cuts)

I guess the smaller part of the cutout may be optional, I just saw the locking feature in your 3D.

There must still be some problem in the outline graphics. Can you copy the Edge.cuts layer to a new project (or delete everyhing else) and send it here?

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It looks like the footprint has an edge with a notch already existing in the Edge.Cuts layer. These Edge.Cuts are an open shape. The 3D viewer has problems resolving open shapes.


A) Save an edited version of the component with nothing in the edge cuts layer and make the cut in your board yourself. [J1 in image] Probably the preferred method.

B) Save an edited version of the component with a closed shape for the Edge.Cuts and use that. This will cause a problem if that cutout overlaps with your board edge. Also, if you place it too far from the edge you will get a hole rather than a notch. [J2 in image] This could cause problems in manufacturing so many not be a good idea.



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fairly simple to do it in a Footprint… have done quite a few of them and always works. But, we all have our preferences…

Here’s an image of something I previously posted that may help…

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You need to think about manufacturability. Inward cuts with square corners is a no-go (unless you want to pay extra for laser-cutting).
The PCB manufacturer cuts the PCBs with mill cutters in vertical spindles, and cutters are… round.
If you strictly need to fit in a rectangular piece to your PCB, use “Mickey Mouse Ears” instead.


Thanks everyone. super helpful. Got it to work and went with the approach in A) above. I had been trying to figure out a way to do J2 and never could get it to line up just right.

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