I'd like to request a video on pcb edge connectors. It seems in the KiCad 6 some features were added to make this easier (e.g. drawing edge cut layers on a footprint). What are the best practices for making edge connectors?
What are the pros and cons of adding edge cut lines to the footprint versus leaving them for the pcb layout? Are there any good libraries for edge pads (e.g. for alligator clips), that aren't found in the default KiCad libary?
Let’s start with the pros and cons of edge-cut in footprints:
PROS:
It can save time when the same footprint with edge cuts is used multiple times across different PCB designs
Your final edge-cut layer on the PCB design would be minimal and simple
If the edge-cut is an integral part of the footprint (say, a mounting hole), By doing the edge-cut on the footprint, you can avoid accidental movement of the edge-cut during the PCB design process
CONS:
KiCad expects one continuous chain of lines with no overlapping or gaps. If the footprints edge cuts do not align perfectly with the boards edge cuts, it can cause issues
It can be more difficult to modify the board outline if the edge cuts are part of a footprint (You have to go back and forth between the layout editor and footprint editor)
Different grid settings on the PCB editor and edge-cut layers on the footprint can affect the 3D view, DSN export, and board manufacturing.
Here are some general tips you can follow while designing an edge connector:
Make the test point bigger than the probe (In your case, make the footprint for the alligator clip bigger atleast 1.5x)
Make sure to give a larger clearance around the edge connector, especially when the edge connector is near copper pours, tracks, or mounting holes.
If the edge connector carries higher current, consider increasing the copper thickness during manufacturing
If this edge connector is very often used, consider going for the ENIG surface finish during manufacturing. It has better wear and tear compared to HASL.
Personally, I would make the edge connector myself, as it would vary from PCB to PCB depending on the functionality.
