Noobie Quick Questions

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1

Hi All,

I am moving from ExpressPCB to KiCAD (now I have discovered it!) and will go through the tutorials. I am doing this as I need a programme that exports Gerber files that I can convert to G Code for my small CNC machine (so I can mill the PCB’s rather than etch them).

I already have my first PCB schematic and board layout in ExpressPCB. I can export a dxf file which I think KiCAD can import. Has anyone done this successfully? If so, this will really speed up my first fabrication.

As I need GCode, I found this programme - https://github.com/Nikolay-Kha/PCBConverter. Again, has anyone successfully used PCBConverter and does it work with the latest version of KiCAD?

If the answers to the above questions is YES! then my life will be complete :smile:

Cheers

Gary

2

To clarify, you have exported copper layer(s) from ExpressPCB in DXF format, and hope to import those into KiCad and then export to Gerber?

I’m not sure if that method will work, I think you would need to convert an arbitrary outline into a zone fill or something, but there may be a way to do it.

3

it seems like converting dxf to copper is possible. I don’t think anything like that exists in kicad and you would need to modify by hand the resulting kicad_pcb.

Why not skip the kicad step and go straight from dxf to gcode?

I’ve used pcb2gcode in the past to make some simple boards on our fireball v90 running mach3. It worked well.

I imagine there is something similar for dxf.

4

Hi Bobc & Starbird,

That was my original cunning plan, but ExpressPCB will export everything BUT the copper layer in DXF. So I don’t have a useable dxf file.

I installed pcb2gcode on my windows PC and ran it but nothing happens.

Perhaps the quickest way is to learn KiCAD. My PCB is not that complicated.

Cheers

Gary

5

Why not export gerber and go from there?

I am sure there are gerber -> gcode converters. Or some gerber viewer can export it to dxf or something similar. (Or at least to something that a gcode converter can use)

6

Hi Rene,

ExpressPCB only exports to its’ own file format, not gerber.

Cheers

Gary

7

That in itself is a good reason to drop it as a bad idea. It’s a lock-in to exclusively use their PCB fab services.

8

For only $60, ExpressPCB will send you the Gerbers :slight_smile:

I remember many years ago looking for hobby level ECAD, the shortlist was something like ExpressPCB, Eagle or KiCad. Overall I’m glad I stuck with KiCad, despite occasional pain.

9

Not now apparently. You can only get gerbers if you buy board fabrication from them (according to their support)

10

I guess that’s their business model.

That at least gives you placement info, for manual PCB trace entry.
Do you have a schematic or netlist for this board ?

Did you try making layers not-copper, to export, or is that doorway closed too ?

11

Hi PCB_wiz,

Yes, I do have the schematic. The netlist is hidden within ExpressSCH. I can’t get the layers not-copper.

I do have the placement info though which I can import into PCBnew. So, replace the component outlines with footprints?

I have just completed the first tutorial so have a simple 555 timer schematic. Quite easy really. OK, so now to start placing the footprints (?) in PCBnew.

Cheers

Gary

12

i had to help one of my college juniors last year… odd procedure but you can get dxf…

  1. install any pdf printer e.g. primopdf
  2. print your expresspcb board as a pdf… remember to print at 1:1 scale
  3. import that pdf as editable in inkscape
  4. as its imported as editable, you can delete unwanted segments, tags, texts, titles, page numbers, etc.
  5. inkscape can save the file as dxf
  6. import the dxf in kicad pcbnew
    :stuck_out_tongue:
13

Hi Apurvdate,

That did it. I have the pcb imported. The tracks are all lines and the pads are missing but that should not be a problem. I’ll check out some tutorials re footprints, etc,

Thanks

Gary

14

Hi Apurvdate,

I have successfully milled a pcb, albeit just the track with no pads. I have written out the proceedure I followed in case your students may find this helpful. In section #3, the dxf imported the traces but no pads. This is not a real problem, I just drilled through the end of each track. I am now going to recreate the boards’ schematic in KiCAD to do the job properly, however, do you know how (in PCBnew) I can add the pads directly onto the B.Cu layer?

Regards

Gary

=====================================================

CREATING GCODE TO ‘MILL’ PCB’S FROM EXPRESSPCB

  1. ExpressPCB

Install the CutePDF printer (FOC)
Print the bottom copper layer to PDF - make sure the ‘print to colour’ box is unchecked.

  1. Inkscape

Install Inkscape (FOC)
Import the PDF - Select Internal Import, maximum precision, no fonts/images, save as a .dxf file (no checkboxes selected)

NOTE: You may also use www.pdftodxf.com

  1. PCBnew

Install KiCAD (FOC)
Run PCBnew
Import .dxf file into dwgs.user layer - this is automatically set for the import but worth checking
Select B.Cu layer
Draw in tracks using the dxf traces as a guide - you may have to set the available track widths in the ‘Global Design Rules’ section
Select PLOT - choose the output directory for the file and B.Cu only, now plot the pcb.

  1. View the Gerber file

Run Gerbview and open the gerber file - check all is satisfactory

NOTE: You may also use www.gerber-viewer.com

  1. PCBConverter

Install PCBConverter (FOC)
Run PCBConverter - open the gerber file, select the output directory and change the file name extention to .tap (MACH3 likes this), generate and write to file. Open the resulting .tap file in notepad. Delete lines #3 [“G92”] and #5[“M03S5000”]. MACH3 does not like these commands.

  1. Mill your new PCB!

=====================================================

15

I’ve had good results using KiCad and FlatCAM.

Plot the copper layers and Edge.Cuts to Gerber files and the drill positions to Excellon, as usual, then

  • import a Gerber file
  • generate geometry
  • generate toolpath
  • export toolpath

this gives you GCode. If you use the same bit for routing the PCB outline and drilling, you can combine the toolpaths for these steps in FlatCAM before exporting.

Protip: use the same origin point for Gerber and Excellon export – either the page corner or the auxiliary origin for both.

1 Like
16

You can use THT & SMD test points as individual pads. You can edit the layer properties as well as pad size, drill size, etc.
Using proper THT pads will also show you proper drill locations instead of erroneous drills at end of track/segments
Make sure you’re using proper grid so that pads are placed at proper spacings similar to actual component footprints

17

Hi GyrosGeier,

That is excellent, thank you. I’ll give that a try today

Cheers

Gary

18

Hi apurvdate,

Thanks. That will complete my existing PCB. Wioth all the help I have received from everyone, I now have a straight forward method for milling PCB’s :slight_smile:

Cheers

Gary

19

Another option may be coppercam (google) it imports gerber files and produces g-code for exactly what you want. I have run some files through and it looks good to me, I have not tried to cut one yet.

20

Hi James,

Thanks. Coppercam looks easy to use. I’ll download a 25 contour trial.

Cheers

Gary