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?
CREATING GCODE TO ‘MILL’ PCB’S FROM EXPRESSPCB
Install the CutePDF printer (FOC)
Print the bottom copper layer to PDF - make sure the ‘print to colour’ box is unchecked.
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
Install KiCAD (FOC)
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.
- View the Gerber file
Run Gerbview and open the gerber file - check all is satisfactory
NOTE: You may also use www.gerber-viewer.com
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.
- Mill your new PCB!