Maker guide
How to prepare a DXF for laser cutting
For laser and CNC. Last updated June 27, 2026.
More cut jobs fail on a bad DXF than on the machine. DXF is the common language for laser cutters and CNC, but a file with the wrong units, open paths, or unreadable curves wastes material before the head ever moves. Here is what actually matters, and the export settings that work.
1. Units: the mistake that wastes the most material
A DXF can declare its units (millimeters or inches) in a header value called $INSUNITS. When it is missing or set to "unitless", your laser or CAM software guesses, and a part meant to be 100 mm can import as 100 inches: 25.4 times too big. Before anything else, set the units explicitly on export, and verify the real size on import. The fastest sanity check is to drop the file into a free DXF unit checker which reads the units and dimensions and flags an obvious mm/inch mismatch.
2. Export R12 for maximum compatibility
DXF has many versions. R12 (internally AC1009), in ASCII, is the most widely read flavor: older LightBurn setups, RDWorks, SheetCAM and most legacy CAM open it without complaint, while newer DXF versions sometimes import empty or scrambled. Unless you have a specific reason not to, export R12 ASCII DXF.
3. Close every cut path
A cut path has to return to its start point. Open paths produce incomplete cuts on a laser, and on CNC they confuse CAM about which side is inside the part, so the toolpath cuts on the wrong side or fails. Auto-traced raster art is the usual culprit: a single line gets traced as two separate open strokes. In Illustrator or Inkscape, select all and join paths, and remove duplicate overlapping lines before exporting.
4. Convert splines and ellipses to polylines
Some laser and CNC controllers cannot read SPLINE or ELLIPSE entities and will silently skip or mis-cut them. If your machine struggles, convert curves to arc-fit polylines on export, or export R12 (which forces simpler entities). The free checker above also warns when a DXF contains splines or ellipses.
5. Use layers for cut vs engrave (or keep it to one)
If your job has both cut and engrave operations, put them on clearly named layers so your laser software can map each layer to an operation. If it is a single through-cut, one clean layer is simpler and avoids confusion. Either way, convert any text to outlines first, so a missing font cannot reflow or drop your lettering.
Export settings by software
Adobe Illustrator
File > Export > Export As > DXF. Choose DXF/DWG version R12, set the unit to match your design (mm or inches), and "Preserve appearance". Outline all text first.
Inkscape
Save a Copy > Desktop Cutting Plotter (AutoCAD DXF R12). Object to Path on everything first so curves export as polylines, and set the document units before exporting.
Fusion 360
Right-click a sketch or a flat face > Export as DXF. Fusion writes clean, closed, real-unit geometry, which is why it is a reliable source for 2D laser/CNC parts.
LightBurn
LightBurn imports SVG and DXF directly and builds the toolpath itself, so you usually do not need to pre-generate anything. Check the imported size against a known dimension before framing.
Before you press cut
- Units set (mm or inches), real size verified on import
- Exported as R12 ASCII DXF
- All paths closed, duplicates removed
- Splines/ellipses converted to polylines if your controller is picky
- Text outlined; cut and engrave on separate named layers
Run a final check with the free DXF unit & size checker, and see the full file-format reference by machine.
Only have a PNG or JPG of your design? Turn it into a clean, closed-path SVG or DXF first with VectoSolve, then run it through the checklist above. Running a laser shop? See VectoSolve for laser engravers.
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