Ground fill does not (always) connect vias to ground planes

[davidperrenoud]

From jerome.b...@gmail.com on July 06, 2012 08:59:24

In the attached example, the parts on the right are set to ground seed (one pad and two vias). Still, when generating the ground planes, the via on the bottom right corner is not connected to ground, neither top or bottom planes.

Vias are used to bind ground planes together (top and bottom planes) and sending signals to ground, so the two vias on the right should be connected to both generated ground planes, since they were set to ground seed.

Or maybe I completely misunderstood the way this should be used.

Attachment: ground_test.fzz

Original issue: http://code.google.com/p/fritzing/issues/detail?id=2095

[davidperrenoud]

From irasc...@gmail.com on July 06, 2012 23:01:06

via with trace directly to gnd pin also doesn't get connected.

Status: Accepted
Owner: irasc...@gmail.com

[davidperrenoud]

From irasc...@gmail.com on July 06, 2012 23:45:24

has to do with the size of the via

[davidperrenoud]

From irasc...@gmail.com on July 08, 2012 02:55:23

the ground fill function clips out copper fill "islands" smaller than certain dimensions, since these cause problems for the fabricator. However, since these particular ground connections are not "islands", but more like traces, clipping should not apply (though these "traces" will still need to maintain a certain minimum width).

[davidperrenoud]

From jerome.b...@gmail.com on July 21, 2012 11:28:22

In the following example, the ground fill procedure clips out all connections of the via. Via is theoretically to ground, but is not connected. Actually the C1 component is shifted 0.25 mm more than the other ones, and there the via accepts the connection. It is arguable that the manufacturer needs some space, but since all the SMD components do have a small copper area between their pad and the via, there seem to be a limited interest to remove the line from the SMD to the via.

Attachment: bug-via.png Main_test6.fzz

[davidperrenoud]

From jerome.b...@gmail.com on July 29, 2012 14:20:58

On the following example, there are three vias. All the vias are set to ground. Two of them are 0.45 mm/0.45 mm, one is 1.31 mm/1.31 mm

Large via : When the via size is strictly larger than 1.3 mm/1.3mm, then a copper blocker next to the via will not prevent the connection of the via to the ground plane (through the copper blocker). (Yes, I need vias as large as that... we found out we can manually solder the nasty packages with exposed pad below passing a thin soldering iron tip through a large via. 1.3 mm is the minimum we manage, so I'd like 1.4 mm or 1.5 mm next time.)

Smaller via on the left : The side via can prevent the connection to ground of the large one, although all of them are set to ground. Probably because the small via “touches” the wire that the ground plane generator adds to the large via. (The purpose of the side via is to follow manufacturer recommendations about putting several vias below the SMD part for better grounding and thermal dissipation.)

Via on the right : a reference, it does what it is supposed to.

Attachment: Main_test9.fzz bug-via2.png

[davidperrenoud]

From irasc...@gmail.com on October 21, 2012 12:16:32

r6586 . Original issue is dealt with. Comments 4 and 5 behave as before.

[davidperrenoud]

From irasc...@gmail.com on October 21, 2012 12:21:37

Issue 2186 has been merged into this issue.

[davidperrenoud]

From irasc...@gmail.com on October 21, 2012 12:22:23

Issue 1900 has been merged into this issue.

[KjellMorgenstern]

None of the reference images from google code are available anymore. Closing this in favor of #3794