This guide shows how to make a DXF file for laser cutting in SchoolCAD, free and in your web browser. A DXF is the 2D drawing file laser cutters and CNC routers read. SchoolCAD turns each part of a 3D design into a flat outline with its holes, full size in millimetres, and lays the outlines out on sheets the size of your laser bed. Students don't need to install anything or make an account.
Step 1: design flat parts
Laser cutting suits flat parts cut from a sheet: a box, a sign, a phone stand, a clock face. The usual way to make one is to sketch the outline, then extrude it to the sheet thickness (for example 3 mm). Holes, slots and cut-outs go in the same sketch, or as later cuts.
Got a drawing already? In a sketch, Insert image brings in an SVG or DXF exactly, or traces a PNG or JPG of a bold, dark drawing (such as a logo) into outlines you can extrude or engrave.
Step 2: choose what to cut
- Nothing selected: every visible part goes in the file.
- Some parts: select them in the Parts list (Shift-click for more). Do this when parts are different thicknesses, which need separate sheets.
- One face: click a flat face on the model to export just that outline.
Step 3: export the DXF
- Click Export, then Laser cut file (DXF).
- Set Sheet to your laser's bed size, or choose Custom size and type it in.
- Set the Gap between parts and from the sheet edge, and tick Turn parts to fit to fit more on a sheet.
- Read the summary line: how many outlines, how many sheets, and any warnings, such as a part too big for the sheet.
- Click Download DXF.
What's in the DXF file
| Layer | Colour | What it holds |
|---|---|---|
| CUT | Red | Outlines and holes to cut right through. |
| SHEET-DO-NOT-CUT | Grey | The edge of each sheet, so you can see the layout. |
| BEND-UP-DO-NOT-CUT / BEND-DOWN-DO-NOT-CUT | Blue / purple | Bend lines on parts folded with Bend or Sheet metal, labelled with angle and direction. |
| NOTES-DO-NOT-CUT | Grey | Bend tables for sheet metal parts. |
Each part is laid out as the outline of its biggest flat face, so check the preview: every red line will be cut right through.
Tip
Most laser software lets you set power and speed by colour or layer. Map red to cut, and switch off or delete the grey and blue layers (or use the blue bend lines as a light score if you want a guide for heating acrylic).
Engraving as well as cutting
To engrave text or a logo, make it a shallow cut on the face of the part (sketch, then extrude with Remove a fraction of a millimetre). For Quick design projects, the laser file has red lines to cut and black lines to engrave.
For a CNC router
The same DXF works for a CNC router. Add Dogbone reliefs to inside corners so square tabs fit routed slots (a round cutter can't make a sharp inside corner).
Common problems
- Too big for this sheet: choose a bigger sheet or tick Turn parts to fit.
- Only one shape came out: a face was selected. Press Esc and export again.
- Parts of different thicknesses: SchoolCAD warns you. Export each thickness on its own.
- The laser cuts the grey sheet edges: delete the SHEET-DO-NOT-CUT layer in your laser software.
More help
- Laser cut file (DXF)
- Insert image and Dogbone
- Forum guides: Laser cut box generator and Phone stand design in bent acrylic
Make your first DXF at schoolcad.app. It's free.