This is my SUCCESS at getting the CNC3018 microCNC machine to engrave trophy plaques using Ubuntu 18.04 (and 20.04 as well), Inkscape with the GCodeTools plugin, and Candle (formerly GRBL). I picked up this CNC thing for $50 from a friend who couldn't figure it out. I tried to do milling with it THE FRAME AIN'T STIFF ENOUGH! So stick to engraving! Actually, it can mill metal, but only 1/8" diameter endmill or less, and it takes FOREVER (like 1 hr to cut 6" of 0.094" aluminum).

== FULL LINEBYLINE INSTRUCTIONS ==
Trophy Engraving using Inkscape, GCodeTools, Candle, and the CNC3018:
1. Open Inkscape
File / New file
File / Document Properties [Shft+Ctrl+D], set size to 55mm x 25mm (plaque size)
2. Create a Text box, pick a font, type in name, subtitle; move to center
3. Extensions / GCodetools / Orientation Points..., I set Zcut to 0.20mm (0.008". Z=0 will be top of paper sheet to start, and there is a thin plastic protective layer on the plaque to cut thru too).
4. Extensions / GCodetools / Tools Library... and OK the "default"
A gray table appears on the screen.
Use the Text tool, change the "diameter" to "0.1" mm; penetration feed to "150"; feed rate to ""; spindle (RPM) to "1000"
5. Highlight textbox with select tool. Click Path / Object to Path, then Path / Dynamic Offset
6. Extensions / GCodetools / Path to GCode...
Click Preferences, change file name, to end in ".NGC" or ".NC"
Set Zsafe height to 0.5mm. This is the height the cutter traverses above the plaque.
Click off of the Preferences tab onto the first tab. This is a QUIRK!!! It doesn't work otherwise!!!
Hit apply.
Image should get full of vector arrows on the text, and no error box.
Check to ensure the NGC file was indeed created.
I like to Undo (Cntl+Z) to get rid of the vector arrows, then Save and Close Inkscape.
7. Open Candle. In a command window, type "./Candle/src/Candle"
In Candle, open the file. It should show up.
8. Ensure the plaque is securely taped down and square in the engraver.
9. Use the Candle Jog controls to move your cutter to the bottom corner of the plaque. Hit "Zero XY".
Go near the middle of the plaque and lower Z bit by bit until the sheet of paper gets fairly tight.
Pull out the paper and hit Z=0.
Hit "Send" and "ignore" if it throws an error at first. The machine should now be engraving! If you want to get rid of the error popup for good, open the *.nc file in a text editor and delete the "%" line at the top. This "%" thing can also freeze the offline controller, so best to get rid of it anyway.
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== INSTALL INSTRUCTIONS ==
See the following:
Install Qt5/Qmake and download Candle from Github: https://github.com/Denvi/Candle/issue...
GCodeTools is available on Github too. Instructions for unpacking are at bottom of page: https://github.com/cncclub/gcodetools .
To create GCode using Inkscape (https://www.ctoom.com/tutorial/howto.... This helped a little bit.
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