Nesting Parts on Sheets

Overview#

Nesting means arranging many part outlines on a sheet so that the material is used efficiently and the cutter moves sensibly. Material is often the largest cost of a laser, plasma or waterjet job, and a good nest can save material over a manual layout (the saving depends entirely on the parts). Fusion has a nesting environment in the Manufacture workspace that takes parts (sheet metal or ordinary bodies), their material and sheet sizes (called packaging), computes one or more nests, lets you compare and edit them, and exports DXF files or hands the result to toolpath generation.

Nesting also exists in less formal forms, such as arranging sketches by hand on a sheet. The Manufacture Nest is the full workflow with studies, quantities and sheet inventory.

Licensing: according to Autodesk's help, creating nests requires the Fusion Manufacturing Extension (the former Nesting & Fabrication Extension features are now part of it); without it you can still use the Compare feature and view reports on nests others created.

Where to find it#

• Nest Preparation: Design > Tools > Nest > Nest Preparation (a Design workspace command per the Nest Preparation reference).
• Manufacture workspace, Fabrication > Nest: Create Nest Study (Manufacture > Fabrication > Nest > Create Nest Study). Edit Nest Study and Edit Nest are on the Browser right-click menus; Component Sources and Compare Nest Studies have their own help topics.
• Browser: a Nest Studies node holds studies, each with nests (one per sheet or packaging). Right-click a study for Edit Nest Study, Generate, and so on.
• Process Material Library: where materials and packagings (sheet sizes, costs) are defined; reached from the nesting dialogs.

Step by step#

Autodesk describes the workflow as: set up shapes with Nest Preparation, add materials and packaging, optionally set Component Sources, create the nest study, view and edit it, compare studies, and export.

1. Prepare shapes#

1. Click Design > Tools > Nest > Nest Preparation.
2. Under Ignore, choose which object types to exclude (Automatic (Sheet metal), Automatic (Sketches), Automatic (Selected entities)). In the Component Type column set how each object is treated: Automatic, Sheet metal (uses the flat pattern), Selected entities (by default the largest face is used for nesting) or Sketches.
3. Set the material and nesting properties for each shape. Fusion's nest help also has pages on arrangement options such as rotation and grain (the NST-ARR-ADV topics); check them for your version.
4. Confirm. Shapes appear in the study dialog later.

2. Define materials and packaging#

1. In the Process Material Library create or pick a material (for example Birch plywood 3 mm, Mild steel 2 mm).
2. Define packaging for the material: the available sheet sizes, e.g. 1220 x 2440 mm or 600 x 400 mm, with optional cost and inventory. Autodesk's help notes that shapes whose material has no packaging associated are left out of the study, and a "no packaging has been defined" error is a common first-time problem.
3. If you cut from remnants, add them as separate packagings with their own sizes and an inventory quantity.

3. Component Sources (optional)#

Use Component Sources to set global parameters and to add sources (designs or components) to the nest, for example when nesting parts from several documents or when multiple quantities are needed.

4. Create the nest study#

1. Click Create Nest Study.
2. Study tab: Set Job QTY (number of finished assemblies; single value or multi-value per source), Stack size (identical sheets cut together), check Automatically Calculate Nest (recommended by Autodesk so the nest is generated when you click OK), and optionally Automatic manage nest so Fusion updates nests when sources change.
3. Shape tab: select the shapes to include. Bind all shapes to sources keeps shapes updated when their material or nesting properties change.
4. Packaging tab: manage which sheets are used. Set Inventory QTY (or leave at infinite), reorder with arrows, and choose a Packaging usage method: As Listed (exhaust each packaging in order), Best Mix (most cost-efficient combination), or Best Size (one optimal size for all sheets).
5. Global Parameters tab: choose Corner Position (where nesting starts, such as Lower Left), Minimum and Maximum compute time (seconds spent arranging), Desired yield (stop early once this percentage of sheet use is achieved), and Remnant Optimization (minimize width, length, or both, to leave a useful remnant).
6. Output tab: Create manufacturing model (needed only for toolpaths and NC code), Show part outlines (adds a sketch for each component; may increase generation time), Include stock (adds a stock body and sketch; with a manufacturing model also adds a remnant cut sketch).
7. Click OK. Fusion computes the nest.

Note: not confirmed in Autodesk's documentation (pages consulted): exactly where part-to-part spacing and rotation increments are set. Check the nest properties and presets for your version.

5. View, edit, compare#

1. Open the nest in the canvas to see parts on the sheet. The Browser lists the nests with yield percentage and sheet counts.
2. Right-click the study to Edit Nest Study, or use Edit Nest on a single nest. In the Edit Nest dialog the Study tab is replaced by a Nest tab showing the material name and thickness (read-only), and the Global Parameters tab can override the study's parameters for that nest.
3. Use the manual edit tools to move or rotate parts, remove parts or add parts, then Generate again if needed.
4. Create several studies with different packaging methods or compute times and use Compare to see yield, number of sheets, cost and so on.

6. Export#

• Export: select one or more sheets in the Browser, right-click and choose Export, then pick DXF (AutoCAD) or MSI (TruNest). For DXF, the Export Configuration Editor controls how data maps to layers. A manufacturing model is not needed.
• Toolpaths and NC: enable Create manufacturing model in the study output, then use the resulting setup to add 2D Profile operations. Use the nest's sketches or part outlines as contour geometry.
• Reports and labels: Autodesk has help topics for nest reports (including customizing a report) and nest labels.

Manual and quick nesting without the extension#

1. Place each part's flat pattern in a single export sketch using Move/Copy and align commands, then export the sketch as DXF.
2. Or export separate DXFs and nest them in the laser's software or in third-party nesting tools (for example DeepNest, which is open source).

Options reference#

Practical nesting rules#

Note: these rules are general shop guidance, not Autodesk data; follow your fabricator's and machine's specifications.

• Spacing: keep gaps of at least 1 to 2 times the kerf for laser and 1 to 2 times the thickness for plasma, to avoid heat distortion and burn through. Waterjet gaps depend on the abrasive jet diameter and piercing needs.
• Edge margin: leave 5 to 10 mm clear at the sheet edges for clamping, rough edges and sheet tolerance.
• Grain and pattern: wood and brushed metal need orientation limits; restrict rotation to 0 and 180 degrees.
• Part mixing: nest parts of the same material and thickness only.
• Common-line cutting: sharing cut edges saves cutting time but is only for stiff, non-warping parts.
• Remnants: record remnant sizes; Fusion's remnant optimization helps keep a large rectangular offcut.
• Time vs yield: the last 2 to 3 percent of yield can take a lot of compute time. Set a desired yield and a maximum compute time.

Tips and pitfalls#

Tip: Run two or three studies (different compute times, packaging methods) and use Compare before committing to the cut.

Tip: Label parts. Engrave a part number inside a non-critical area or lightly mark the sheet, so you can find parts after cutting. Nest labels and reports can help on the shop floor (verify in your version).

Warning: If a part is missing from a nest, check that its material has packaging, that its size fits the sheet, and that it is included in the Shape tab. The "no packaging" error is the most common.

Warning: Nests are tied to sources. Large design changes can invalidate a study; regenerate and re-check before exporting.

Warning: Nesting does not know your material defects or grain unless you encode them. Inspect the sheet and mark bad areas by hand or exclude them with a remnant.

Practice exercise#

Create a design with three different sheet parts (for example a bracket flat pattern, a plate with holes, a disc) all in 3 mm mild steel. In Manufacture, open Nest Preparation and select all three. In the Process Material Library create Mild steel 3 mm with a 1250 x 625 mm packaging. Create a nest study with Job QTY 20, Best Size, desired yield 85 percent, and compute time between 10 and 60 seconds. Export a DXF per sheet. Expected result: one or two sheets with a yield figure shown in the Browser, DXFs that open in a viewer with all parts and the sheet boundary. Then create a second study with a different compute time and Compare the two.

Related#

• Cutting toolpaths with 2D Profile
• Exporting DXF and SVG
• Sheet metal flat patterns for cutting
• Kerf and tolerances