I am inspecting a few PCB designs and seeing some unusual features and would love help identifying them.

In two of the attached images, there appear to be unfilled holes that go all the way through the 2-layer PCB. The placement of the holes doesn't seem to align with locations for optional placement of components that just were not populated on the PCB.

One image has a array of small metal "stamps" in a large metal area.

Final there is an array of small holes that appear to go through the top side coating layer, but not through the board. They even overlap the edge of a metal area. Strange.

If you have any ideas, I would love to hear them! Thanks.

 

Hello,

Have a look at the following page about thermal vias:
https://artist-3d.com/thermal-vias/

Bertus

 

Thanks, Bertus! I suspected heat might be at least part of the reason for them, but wasn't certain. I really appreciate the help!

 

Also, the vias are used to connect copper on different layers.
Example: You have ground in a local area on the top layer. There is an inside layer (not seen) that covers the entire board and is ground. The two grounds are connected with many vias to make a good connection.

 

Hi Dale,
You may find this PCB , PDF useful.
Do a page search for 'via'
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