Probelm with adding a filled zone

I’m not sure I’m doing this right. A short written question with 3 inserted images. But I don’t see the images, just a (possible) url? to them. Please excuse if I’m doing it all wrong and, if so, please advise of correct procedures.

My 1st question

I have what, seems to me, a simple pcb for cnc in Kicad but I’m having a problem. I need a connector mounted on my 3d printer.
See Dwg-1

Made a very simple schematic in KiCad.
See dwg-2

These had jst-xh3 footprints assigned to them. Which gave the following PCB.
See Dwg-3

This would be fine for photo resist-etching. But I need it for use on a cnc machine. This will require isolation routing. I understand Kicad enables this by:
Adding a filled zone and selecting the “GND” net. But when I try this the Copper Zone Properties only lists .
I must be missing something or perhaps for such a simple pcb I’m approaching this all wrong.
I found nothing about this in the FAQ, but that might be because I didn’t know what to search for.
As you can probablyguess, I’m just getting started with KiCad, and at 87 years old I need all the help I can get.
Any help would really be appreciated.
(MOD EDIT: Removed email address. Please contact via PM.)

Hello and welcome.

All three images are fine.

A couple of comments:
If you invert one 3 pin socket, the layout is even easier.
Have you thought of Vero Board if the pins are .1 inch spacing.

I can’t help with your problem as I’m not into CNC routing. Many are though, in particular this guy @BlackCoffee .
You may have to be patient for a reply to your problem… time zones and such.

Hi Larry,
Starting KiCad at the age of 87, my respect. Hope there is a badge for that.
Your pcb:
I cannot see an outline of the pcb, draw that on layer edge_cuts.
The filled zone does not show, press b on you keyboard to make KiCad fill the zone. Left hand side, there are buttons to show/hide fillings, find and use them. Not quite obvious, it took me a while to find that.
That will at least show the gaps you need to route, but no idea how to get there.

Well, you do not have your pins 2 on both connectors connected and labeled as GND to be able to pour a filled zone.
2 ways of drawing your schematic:

and the resulting board:

For isolation routing, generate gerber files and use a different tool such as FlatCAM.

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I read another complaint about pictures being delayed a bit yesterday.
There is some complicated method behind the hosting and rendering of pictures and apparently it has some hickups lately.

KiCad does not render zones, unless it can connect them to something.
Usually this has at least two advantages:

  1. Unconnected copper is no benefit at all, so it’s good if it’s not rendered.
  2. If you see a gap in a zone (for example surrounded by other tracks) then it’s immediately clear there is a problem area you have to pay attention to.

There are at least 2 programs I know for generating vectors for PCB milling. FlatCAM (already mentioned) and CopperCAM, and there may be more. I have not used these except for a very small peek at their capabilities., I have toyed briefly with such a program and I think I saw an option for milling just outlines, or also milling area’s.

@larsnavy I’ve been CNC milling my PCB’s for 20 yrs so, I can help… I’m 73yrs old.

Re: Kicad and Milling

Once you get good Gerber files, you can use them in Coppercam and output Gcode for milling.

Re: CopperCam
That is all I use for milling PCB’s - I threw away Flatcam and other’s. Personal preference…

You can download CopperCam here - the download is Free. Without paying for it, it’s Limited to lower number of cuts and thus, will do many more than your PCB shows. It’s also easier to use (compared to Flatcam).

The Kicad Process and the Gerbers:
If the parts are on Top of the PCB and traces are on the Bottom, you’ll need to Horizontally Flip the PCB in Coppercam so milling the traces will be correct.

Don’t flip it in Kicad - you’ll flip it in CopperCam. In addition to the traces, If you also have text to mill on the Bottom side of PCB, Mirror the text in Kicad.

Add an Auxiliary Origin in Kicad. It’s location is up to you but, think of it as the Home position of the Tool-bit. CopperCam will use this as it’s Origin (if you setup CopperCam correctly).

There’s more detail you need but this forum may not be the place for further help on Milling it.
You can send me a Personal Message from this forum and we can take it from there…

Here are some Images as a Head-Up… we can go into details through Messaging or Email

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Wow! In less than 24 hours, 18 replies to my questions about posting and isolation milling.

I believe I now understand about posting with images. Actually I tested that with (what I thought would fail) my question about isolation milling, but when I inserted the images in my post all I got was 3 url’s (??). However when I posted the message, ”magically” they turned into the images. So I guess we can close this topic.

I got 7, so far, replies to my question about isolation routing (really fill zones) but I’m going to have to go through them all a few times to see if I understand what I need to do. It looks like my main problem was, in this simple circuit, there is no ground. I’ll work on that. And will look into CopperCam.

I am impressed with such quick, and very helpful, responses. And I want to thank everyone who replied.

Larry Nelson

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Generally speaking, Isolation is not a part of Gerbers.

If Photo-Etching, all copper not Inked will be removed (thus, Isolation)

If CNC Milling, the Tool-Bit diameter (and settings in, say, CopperCam) take care of the Isolations…

@larsnavy there is one more point in filling zones:
In your case, a filled zone needs to be generated to generate the gaps, that you route later on your machine.
In your first schematic, there is no GND, pins 2 are left unconnected. If that is OK for you, keep it like that. But then the zone will not fill, as it has no signal to connect to. In most cases that’s OK, as “islands” of unconnected zones are not wanted. In your case, that dosn’t really matter.
So why not using a zone with islands? Might even be easier to route with no spokes at GND-pads.

Nothing abnormal here. Sometimes, people have their problems solved in minutes :slight_smile:

Well, after spending a few hours reading these (many) helpful replies to my post about isolation routing, plus a little more internet searches, I decided that BlackCoffee and others have the right approach to my simple problem. Ist, schematic and pcb layout in Kicad, just as if you were going to use photo-etching, then export gerber to, in my case , FlatCam ( I’ll try CopperCam later). Then have Flatcam do the isolation routing… I tried it with a simple thermistor/mosfet fan controlled switch circuit and it worked just fine, and fast. So that’s the method I’ll use from now on. Again I want to thank all of you for getting me headed in the correct direction for cnc pcb routing. Now I just have to get the gcode to the router and practice till I get it the best board I can. So I guess we can call this question of mine closed. Thanks again, Larry N.


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