Hi, KiCAD Newbie Here
I am transferring some footprints into KiCAD format and I was wondering if there is a document that provides some detail, and maybe examples, for the various Pad Shape definitions. Especially the custom definition. I gather that I just build the copper shape from lines and polygons and such with a SMD pad added for contact to the copper shape.
I will dump some footprints to a printer but a document sure would be nice!
Also, where does the “pretty” word come from for footprint libraries? Are there any ugly footprint designs to avoid?
Hahaha, some old timer developer chose that name and it has been carried through the versions. (Speaking for myself I would have chosen .nifty. Maybe I’ll create a Nifty computer language so that the programs are .nifty.) But for your own footprint libraries you can choose any name, even .ugly, the software doesn’t care. Sorry that’s anthroposomething or other.
PS: thinking about it, it would have to be after Windows acquired LFNs. So not in the DOS version.
Place a pad in your Symbol editor, Right click and open properties or right click an existing pad in your PCB editor then open properties and explore.
The Line icon will not fill a shape. Use the polygon shape to draw lines, right click on the border and “Fill” to create graphic shapes. Combine a pad and a graphic shape and use “Finish Pad Edit” hotkey E to combine the pad and the Graphic Shape.
I supposed in Documentation - PCB editor pdf it is but the “Creating and editing footprints” chapter contains: “This section of the KiCad documentation has not yet been written.”
So…
Search KiCad footprint library for interesting footprints and explore how they are done.
For me interested was for example one of: QFN-32-1EP_4x4mm_… because of corner pads shape and paste openings at EP:
1) What is this need I see to put vias on pads in libraries ???
I do not put vias in my parts libraries. That should be the PCB person doing that. Sometimes ONE via will be enough… AND- the vias you use on that PCB will likely depend on what else is on the PCB. IE you might have 0.6/0.3 in your library but if it’s a simple PCB, OR the PCB is a 2.5mm thick etc that might be costly / difficult. so leave the vias until PCB routing time, and place technbology appropriate vias …
2) I think its a bit overboard on the main pad , all those different shapes and sizes. ridiculous. Suggest a bunch of 1x 1 or 1.2 x 1.2 apertures. I usually aim for no more than 60% pad coverage unless it is some sort of high power device…
3) yes, often the pads on the corners for some QFNs are truncated. I’ve never seem them cut an angle though and I would strongly advise not doing this because you likely breach the aspect ratio limits for height, width, thickness and ball size. You are unlikely to get paste adhesion in those corners.
As I know at what PCBs I will be using my footprints I like to have vias and stencil openings defined once forever and not to think about it again and again with risk to forget something.
You can always use footprint version without vias defined in footprint.
I agree. But it was an example to explore how it can be done.
That is pretty much how it works. The original idea is to press [Ctrl +e] to enter “pad edit mode” and then add graphics items, and press [Ctrl +e] again to exit pad edit mode and add the graphics shapes to the pad. (Maybe later?) this evolved into “overlapping graphics” when the pad edit mode is exited, and this makes it’s definition a bit wider and easier to use.
Try this (in the footprint editor) for example:
Draw some graphic lines or a polygon on a copper layer.
Put a pad on top of your graphics.
Press [Ctrl +e] twice to both enter and exit the pad edit mode.
