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Are pads from the EAGLE "testpad"-library printed or separately bought and mounted?

E.g. "testpad / PTR1"

TEST PIN Footprint: B1,27 (Version 1) TEST PAD 3D Package: B1,27 (Version 2) TEST PAD

Null
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Galaxy Stuff
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  • Test pads are just pads on the PCB, you don't fit anything there. Test pins are through hole parts that may (or may not) be fitted. Also see this question: https://electronics.stackexchange.com/q/79224/79028 – Richard the Spacecat Sep 12 '19 at 10:50
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    I still wonder why did you ask this. Did EAGLE show some (fake) 3D parts in place of the footprints, which confused you, or? :/ – Richard the Spacecat Sep 12 '19 at 11:08
  • Look at the footprint and decide if the features made on the board are what you want, it is that simple. If you don't find what you like, make your own. – Chris Stratton Sep 12 '19 at 13:04
  • You *can* get [target pads](https://www.digikey.com/en/products/detail/mill-max-manufacturing-corp/1618-0-57-15-00-00-03-0/12323665) that are intended to provide a reliable flat contact for spring-loaded connectors to mate to, but I've never seen the point of them. The [ones with dimples](https://www.digikey.com/en/products/detail/mill-max-manufacturing-corp/1945-0-00-15-00-00-03-0/5176095) at least provide some self-centering, though. – Hearth Dec 22 '20 at 16:21

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I currently have no access to this library, but the answer can be given without knowing. Or better, you can look for things letting you decide yourself.

If a testpad was a part to buy, the library probably will provide some manufacturer data. If not, it is very likely that this testpad is solely build from PCB layerstack. Furthermore testpads which are soldered to the top or bottom layer of the PCB are very rarely used. They are needed only when a high testcount is needed or accessability is a problem within design. They are expensive and therefor they are avoided.

Just read the metadata of the library and the library elements. (thanks to @ChrisStratton)

There are some signs to determine, if a testpad is designed for some component to be soldered onto. If there's a shape in the paste and/or glue layer or if the testpad has a shape which is not circular or square.

Anyways, you should not use standard libraries shipped with your EDA software without checking it thoroughly against your own design goals as well as any available information from PCB/PCBA-manufacturer. If in doubt, better build your own library (Testpads are not that difficult to create).

Ariser
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    This is not actually true. While arguably unjustified soldered points are quite common in low volume boards, and a pcb library often does not have information for the manufacturer of generic items. The asker needs to inspect the footprint, more than the metadata. – Chris Stratton Sep 12 '19 at 13:05