Cleaning a customer DXF: dimensions, title blocks, bend lines and everything else that must not be cut

What a cut file should hold

SendCutSend's checklist for its own customers is a good model: no dimensions, annotations, construction geometry or drawing borders; text converted to outlines; no open contours; stray points, duplicate lines, empty objects and text areas removed; the part at 1:1 in mm or inches. Its AutoCAD guide asks for anything that is not cut on separate layers from the cut and bend geometry.

Junk by type

The names are matched anywhere in the layer name, in any case: CENTERLINE and DIMS are ignored, but a layer called FRAME or CENTRE is cut. Hidden lines drawn on layer 0 with a dashed linetype are cut too, because Zorocut reads layer names, not linetypes.

Bend lines from flat patterns

• Fusion's flat-pattern export always includes the bend lines; outer profiles, interior profiles, bend centre lines, bend extent lines and text each go on their own layer.
• SolidWorks makes bend lines optional in the flat-pattern export and draws them dashed.
• CypNest can identify bend lines from SolidWorks drawings and shorten them automatically — useful when the shop marks them instead of cutting them.
• For a part that is only cut, leave them out. To mark bend positions, put them on a layer named MARK: a layer called BEND_MARK is still ignored, because its name contains BEND.

Duplicates, stray points and fragments

• Duplicate lines are cut twice. SheetCAM's manual says overlapping copies normally confuse it, and its import can delete all but one; CypCut removes duplicates on import too. Zorocut removes exact copies on the same layer (ends within 0.005 mm) and says how many. A copy on another layer, or a line that only partly overlaps, stays: it shows up as a “more than two lines meet” warning or as an open contour.
• Tiny graphics from stray clicks cause abnormal positions in machining, CypCut's manual warns — that is what its Remove Trivial and CypNest's Delete Invisible are for. Zorocut drops specks smaller than 0.2 mm both ways and reports them; POINT entities are skipped.
• Open fragments longer than that stay open contours and block the export of that geometry: delete them in CAD.
• Text that is a note goes, text that is a part number may be a mark — see text in a DXF.

Choosing the layers

Zorocut picks layers by name. Names on the list above are left out; a name containing MARK, ETCH or SCRIBE becomes marking, ENGRAV becomes engraving, and every other layer is cut. There is no per-layer switch in the app, so when the guess is wrong, rename or delete the layer in CAD; the pre-cut check lists every layer it ignored. At the machine, CypCut does the same job with layer mapping: BOCHU's tutorial maps an unwanted text layer to layer 0, which is not processed.