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Slicing and lamination

· Fox Bright

Split any solid into layers the thickness of your sheet, arrange them on the material and cut. Bigger than a 3D printer can manage, and every layer is one flat outline.

A Fusion model of a movie camera built from stacked slices, with the components list showing dozens of layers.

Slicing turns a solid model into a stack of flat contours, each one the height of the sheet you are cutting from. Stack them back up and you get the object. It is how topographic maps get made, how a lot of stage props and architectural models get made, and how I built a life-size movie camera from 1" foam when it was far too big to print. The aesthetic is stepped, like a 3D print’s layer lines but bigger, and you can lean into that.

Exploded view of a sliced movie camera model with layers spread out in Fusion
The camera taken apart into its slices. Each one gets cut on its own, so there is room to add detail to individual layers.

Make something to slice

Any solid works. For the demo I made a pencil holder: a circumscribed polygon of 20 mm radius on the ground plane, an offset plane 100 mm up, then Project the polygon onto the upper plane (projection link off) and rotate the copy. Loft between the two sketches for a twisted solid, then Shell the top face at 3 mm to hollow it out.

Slice it

The slicing template is a Fusion file with a stack of construction planes spaced at the material thickness. Its parameters are material_thickness (2.8 mm for our plywood), target_height, and layer_count = target_height / material_thickness. Insert it into your design and make sure your model sits on the origin so the planes pass through it.

  1. Look from the side, orthographic, so the planes read as lines.
  2. Split Body. Body to split: your model. Splitting tools: every plane that crosses it. The planes are infinite, so only the vertical position matters. On a slow machine do this in batches.
  3. Hide the template. The Bodies folder now holds one body per layer.
  4. Select all the bodies, right-click, Create Components from Bodies. Arrange only works on components.
Fusion Split Body dialog with a blue pencil holder crossed by many horizontal planes
Split Body with the template planes selected. Each plane becomes one layer boundary.

Arrange and export

Arrange packs the components onto a sheet size you define, in the most efficient layout it can find.

  • Envelope: a plane (the bottom origin plane), 600 × 300 mm for our laser bed.
  • Placement clearance 0 for the laser, a small frame width around the edge, object spacing 0.
  • Select every component. Check nothing was left out.
Fusion Arrange dialog with hexagonal slices nested on a rectangular envelope
Arrange nesting two dozen layers onto a 600 × 300 mm envelope. About half the sheet is used.

Then one more sketch on the bottom plane: Project each arranged body to get its outline, with projection link on so edits flow through. Finish the sketch, right-click it, Save as DXF. That file goes to the laser.

Putting it together

Layers want to slide around while the glue sets. Put a dowel hole or two through the model before you slice, or make the shape slightly asymmetric so each layer only fits one way. Number the layers as they come off the laser.