How to Prepare DXF Files for Laser Cutting: A Checklist
Scale, closed contours, layers, spline conversion and minimum hole size: a checklist so your laser cutter can cut your DXF file without asking questions.
Table of contents 8 sections
A laser cutting machine treats every line in your DXF file as a cutting path. One extra line, an open contour or the wrong scale leads to faulty cuts or a delayed quote.
In short: save the file at 1:1 scale in millimetres, close all contours, remove overlapping lines and delete anything that should not be cut (dimensions, text, frames).
1. Scale and units
The DXF should be drawn at 1:1 scale in millimetres. Make sure a 100 mm part really measures 100 mm when the cutter opens the file. A file drawn in inches can appear 25.4 times smaller or larger. Stating the drawing unit in the quote form removes this risk.
2. Closed contours
Every cutting path must be a closed shape. Lines whose ends do not meet prevent the machine from completing the path. Join lines in your CAD software (e.g. with a polyline/join command) to create single closed contours.
3. Overlapping and duplicate lines
Two lines on top of each other can make the machine cut the same path twice and burn the edge. Most CAD tools have a command to find and delete duplicates (e.g. OVERKILL).
4. Splines and curves
Some cutting software cannot interpret splines correctly. Converting curves into polylines made of arcs and line segments improves compatibility. Saving the DXF in a widely supported version such as R12 or R2000 also reduces opening problems.
5. Remove elements that should not be cut
Dimension lines, text, title blocks and frames should not be in the cutting file; keep them in the PDF drawing. If you want text marked or engraved, put it on a separate layer and name the layer clearly (e.g. “ENGRAVE”).
Common mistake: DXF files copied from an assembly drawing that contain several parts and dimensions. Send a separate, clean file for each part with cutting contours only.
6. Minimum feature sizes
Very small holes and narrow slots can be laser cut but may lose quality. As a general rule, avoid hole diameters smaller than the material thickness, especially on thicker sheets. Also leave at least one material thickness between holes and the part edge.
7. Kerf
The laser beam removes a thin strip of material. The cutter usually compensates for this kerf on the machine, so you do not need to add an allowance to the drawing. Draw the part at its final dimensions.
If the part will be bent after cutting, prepare the flat pattern with bend allowances already calculated, or send a 3D model of the bent part and leave the flat pattern to the manufacturer. In that case, a sheet metal fabrication request is the right choice.
Checklist
- Drawing at 1:1 scale in millimetres
- All contours closed, no duplicate lines
- Splines converted to polylines
- Dimensions, text and frames removed
- Marking/engraving on a separate layer
- Hole sizes and edge distances suit the material thickness
- Material, thickness and quantity entered in the quote form
Upload your DXF file, choose material and thickness, and get offers from manufacturers who can cut it.