Nesting software for laser cutting

What the laser changes

The goal is the same as on any table: the most parts out of every sheet. What changes is how close you can go, how small the parts can get, and what the cut does to the parts around it.

1. The kerf is narrow, so spacing is about heat and support

A fiber or CO2 beam removes a sliver of material, a fraction of what a plasma arc takes. So on a laser the gap between parts is rarely set by the kerf. It is set by two other things. On thin sheet, parts packed shoulder to shoulder pile heat into the same small area, and the last edges cut come out discoloured or slightly out of shape. And once a part is free, it sits on slats: a small part that drops or tips can catch the head on the next move.

In practice that means a laser shop can run a tight gap, but not the tightest gap the beam allows. Start from a spacing you know cuts clean on your thinnest material and tighten it on thicker sheet, where heat matters less.

2. Small parts and big holes

Lasers cut small detail well, so laser jobs tend to mix large parts with many small ones: tabs, washers, gussets, brackets. That is exactly where true-shape nesting pays. The middle of a large frame or ring is good sheet, and small parts belong there instead of on a fresh corner of the next sheet.

There is one catch, and it is about cut order rather than layout. A small part sitting inside the hole of a bigger one must be cut before that hole, or it falls with the slug. The same goes for any part: its holes should be cut before its outside, so the part does not shift while the beam is still working inside it.

3. The laser can mark as well as cut

Part numbers, bend lines and orientation arrows are cheap to engrave at low power, and they save a lot of sorting at the press brake. But marks only help if they arrive on the sheet attached to the right part, rotated and mirrored with it.

4. Common cuts work well on thin sheet

With a narrow, consistent kerf, two straight-edged parts can share one cut: one pass separates both, with less travel and fewer pierces. On a laser this is most useful on thin sheet and on rectangular parts in quantity, where the shared edges add up fast.

Small hubs nested inside the holes of the rings, on one 120 × 60 in sheet.

What to set, and why

• Part spacing: the clean-cut gap for your thinnest material, as the job default. Override it per part when one part needs more room, for example a long thin part that warps.
• Sheet edge margin: the border your clamps and the sheet's own edge quality need. Parts never go closer to the edge than this.
• Rotations: four quarter turns is a good default for sheet with no grain. Allow free rotation for awkward shapes, and lock it for parts with a brushed finish or grain direction.
• Mirrored copies: left and right hand parts are counted and nested as their own quantities, so the pair always comes out complete.
• Sheet sizes: list every size on your rack. The densest packing is not always on the biggest sheet.

Kerf compensation is a different setting from part spacing. Spacing keeps parts apart on the sheet. Compensation offsets the beam path so the finished part comes out to size, and it belongs in your CAM software, along with lead-ins and cut order.

Where SheetNest fits on a laser

SheetNest does the layout and hands a clean drawing to the software that drives your laser:

• True-shape nesting. Parts interlock by their real outline, and small parts fill the holes of big ones.
• Inner contours on their own layer. The exported DXF puts holes on 01_CUT_INNER and outsides on 03_CUT_OUTER, so your CAM can cut inside first without guessing.
• Engraved marks that travel with the part. Anything you draw in yellow is never cut. It moves, turns and mirrors with its part, on screen and in the exported DXF, on the layer you drew it on.
• Common-line cutting. Choose per part whether it may share a cut with any compatible part or only with copies of itself. How common-line cutting works →
• Your sheets, your spacing. Per-part spacing, a sheet edge margin, and saved sheet presets. Drag parts by hand afterwards and the spacing still holds.
• A report for the machine. One PDF page per layout with the sheet drawn to scale and every part numbered.

It imports the DXF drawings you already have, and unfolds 3D STEP or IGES sheet-metal parts to flat patterns. It runs on Windows 10 and 11, fully offline, and it is free and open source under the MIT License, with no account and no licence key.

Download SheetNest for Windows

It does not replace your laser's CAM

SheetNest decides where the parts go. The software that came with your laser decides how the beam cuts them: lead-ins and lead-outs, micro-joints, cut order, power and gas settings, and the program your controller runs. SheetNest exports a DXF, and from there your machine setup carries on unchanged.