Laser cuts twice: check duplicate geometry and pass settings

Watch the cutting preview before changing power or speed. A repeated path can come from overlapping entities, multiple operations or an intentional pass count.

Separate file duplicates from repeated operations

Inspect the layer pass count and check whether the same outline belongs to more than one cutting operation. In a copy of the drawing, select and temporarily move one suspect outline. Another line underneath indicates overlapping geometry. Undo the move before continuing. Also inspect shared edges between neighbouring parts; they may represent two separate contours rather than a duplicate object.

Remove only the duplicates you identify

LightBurn 2.1 documents Edit > Delete Duplicates for shapes with identical size and position. Use it on a copy, then inspect the preview. Nearly coincident paths or differently segmented curves may need manual comparison. Removing an entire nearby contour can delete a required part or hole. Confirm the part count and dimensions after cleanup.

Understand what DXF Medic checks

DXF Medic can report and weld duplicate vertices within supported geometry. That is different from a demonstrated detector for every duplicated entity or overlaid contour. Do not treat a clean report as proof that the laser will traverse each edge once. Reopen the final export in the cutting application, inspect pass counts and operations again, and confirm the toolpath preview.

Sources

• LightBurn 2.1 Edit menu reference