Large polygonal traces

[acisternino]

Hi all,

I am trying to recreate an old THT PCB in KiCad (5.1.x) and I am currently routing the power section of the board.

The original board is routed in a style where copper occupies all the available area and traces are actually “carved” out by separating areas with a constant width gap.

I find this type of design quite difficult using copper zones because IMHO they work better when are used for a very small number of nets that cover a larger area. Designing complex polygons whose borders should always be at the same distance requires continuously adjusting corners and priorities.

Is there a better way of doing similar routing?

I actually think that this could be a very useful feature for a future release. A sort of “subtractive” routing where one draws the void between copper areas instead of the opposite. Again IMHO, many of the basic algorithms needed for such a design technique should already be available within KiCad’s code base.

Thanks in advance.

[HiGreg]

What about using tracks to define the edges of the zone. Turn off the “delete existing” track option on the push-and-shive router. Then you can define each side of the polygon with tracks. You might then be able to fill between tracks with zones. Not sure about that.

[craftyjon]

@acisternino

I actually think that this could be a very useful feature for a future release. A sort of “subtractive” routing where one draws the void between copper areas instead of the opposite.

This is how “plane layers” in Altium work. It’s an interesting idea.

[eelik]

I believe this should be doable with a python script. Unfortunately I don’t remember the name of the technique, but in this forum there was discussion about a style of designing a board which can be mechanically routed with a router bit so that there’s no need to remove any more copper than necessary. Creating such shapes is of course a mathematical/geometric problem which can be calculated with a script. Basically you would start with lines and widen each one of them at the same time with the same pace until they (almost) touch each other.

[paulvdh]

A search for Voronoi brings up 2 hits, including one with an actually routed board, so someone on this ball of dirt can do it.

Widen/thicken PCB tracks - aside from zones? (maximise surface area; Voronoi)

Hi all, Whenever I’ve routed my boards, I’d often first start with the thinnest track, do the routing, and then I’d thicken the tracks wherever there was space for it - even when you do photoresist, if there is a lot of metal to be removed from the board (as on the board right on pic below), then depending on UV light or acid freshness, one might end up waiting long enough for the exposed metal to be removed, so the acid starts eating into the tracks. Which is why I’ve always thought - the less…

A more general search brings up more and more general results.
https://duckduckgo.com/html/?q=kicad%20"voronoi"

The first thing this reminded me of however was of very old schematics in elektor Magazine. I’m almost certain these were made without a computer, but with the black tape, then corners filled in and the PCB etched in negative. They had a very distinct look.
Here is a sample from 1975

[Piotr]

@paulvdh

I’m almost certain these were made without a computer, but with the black tape, then corners filled in and the PCB etched in negative.

I suppose it was painted by hand with black ink at transparent technical calque. It looks like PCBs I have done as a child. I painted it directly at PCB and filled all unused regions because I had only 1kg of FeCl3 for all my life.
In my first job we designed PCBs using black DIP sets and black adhesive tapes (several widths) to make connections (used on transparent technical calque) - they looked differently. That tape couldn’t be shaped so flexible - you rather had a serie of strait lines.

[acisternino]

Thanks everybody for the replies.

I’ll try @HiGreg’s suggestion but it seems quite clunky.

The other approaches sound interesting but definitely more difficult.
Well, I planned to look into pcbnew’s Python API sooner or later so maybe this is the right time to do it.

[paulvdh]

The screenshot I posted from the 1975 Elektor board has the same style as your power supply board?

Is this just for this one board, or are you planning to do more similar projects in the future?

If it was just for this one board, the best approach is probably to scan the board with a flatbed scanner and put it in a graphical drawing program and then clean it up a bit:

• Put pins of components on a grid to correct for deformities.
• Enhance contrast.
• Retrace from pixel to vector format.
• Maybe use svg2shenzhen to turn the artwork into a PCB to make Gerbers.

If you’re planning on multiple projects, then a script approach seems more appropriate.
A general search gets results for the magic word “Voronoi”, such as the openvoronoi project.

ferdymercury has been working on a
Zuken CR-5000 to KiCad converter

In his importer he makes much use of zones. In the thread below you can sample a KiCad PCB he made this way.

Copper pour not filling in small zones, no matter the clearance

I have a copper zone that is fairly small and does not want to fill. I know that I could create a wide copper track instead, or a graphic polygon on the F.Cu layer, but this is a script-converted board and I would like to know if there is a setting to force this copper region to fill instead of doing hacky replacements. I tried to set the clearance to zero, the priority high, etc. but none worked. Any ideas?Thanks in advance. [image] I attach here the PCB. Zone is in coordinates 35.5mm, -44.7…