Author Topic: Symbol/footprint sites and licensing  (Read 3532 times)

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Offline GabrielBlackfoxTopic starter

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Symbol/footprint sites and licensing
« on: March 27, 2024, 07:08:37 pm »

I usually make my own symbols and footprints when working in KiCAD. This is becoming annoying, so I've started looking at sites like ultralibrarian or snapeda to make my life easier. However I'm not entirely convinced if the symbols/footprint they offer a free to use, especially in commercial applications. They state "free access" everywhere, but that's not very straightforward. Like... free access and then you have to pay a licensing fee for every manufactured device. Does anyone know the legal side of things regarding using these sites (or others you may know)?

Offline thm_w

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Offline Uky

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Re: Symbol/footprint sites and licensing
« Reply #2 on: March 31, 2024, 03:47:09 pm »
Recognizing the efforts made by the operators who makes symbols and footprints available, I have to comment on this subject.

Now the grunt...

I have tried from time to time to use free symbols and footprint providers but in the end reverted back to make my own. There are several reasons for this:

1. Footprint naming conventions differs between the sites.

2. Padstack naming conventions differs between the sites.

3. Many pad stacks follows a US standard where the copper and solder mask dimensions are the same. The board manufacturer in the US then adds the appropriate "swell" to the mask. In Europe, it is customary to define this already when creating the pad stack. Some CAD-systems can do this on the user level when creating the Gerbers. Some cannot.

4. In far to many cases, there are unneeded details created in the footprints.

5. Silkscreen widths are way to fat or created above pads. Sure, there are utilities that will remove lines that crosses pads but I prefer doing it right the first time.

6. Silkscreens are created when not needed for eg. microminiature footprints.

7. Vital details have been found to be missing, like perimeter information in an assembly/documentation layer for connectors that should be allowed to overhang board edges or polarization key graphics created in such a way that it is underneath the footprint when placed on the board above other components.

8. Footprint court-yard ("DFM" shapes) has been found to be wrong. Either too large or to small.

A ready-made footprint can be a time saver but once the local lib starts to get cluttered with padstack names or footprint names that all follow different standards the situation gets out of control.

As for Schematic symbols, they are often created with the connecting pins in a disorganized manner, eg. not having inputs to the left and outputs to the right, or not grouping supply and GND pins together.

I prefer doing it right the first time.
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