Deakin Researchers Print Rotary Kirigami Cylinders That Snap Into Shape

Rotary 3D printing is starting to produce genuinely useful parts, not just curiosities. A team at Deakin University in Australia, working with Seoul National University of Science and Technology, published a study in Progress in Additive Manufacturing showing how kirigami-inspired cylinders printed on a rotating mandrel can be programmed to snap between different stiffness states. The resulting parts behave like mechanical memory devices: the same geometry can act stiff or compliant depending on how it is loaded and tensioned.

How the printing works

The team designed the cylinders in Rhino using Grasshopper, then sliced them in Cura and post-processed the G-code to run in rotary mode. The printer is a Snapmaker 2.0 A350 fitted with a rotary module. The B-axis rotates the mandrel while the extruder deposits material in continuous circumferential toolpaths. That approach eliminates supports and produces a seamless cylindrical shell with a smooth inner surface.

Material choice matters here. The team printed in ESUN eTPU-95A, a flexible TPU filament, at 220 C with a 0.4 mm nozzle and 0.2 mm layer height. The first three layers ran at roughly 10 mm/s for bed adhesion on the rotating mandrel, then speed increased to 25 mm/s. The TPU choice is not incidental: the kirigami hinge designs rely on the filament's flexibility to produce snap-through behavior.

Kirigami cells as mechanical programs

The cylinder walls are built from bistable kirigami unit cells. Each cell can exist in one of two states: closed or expanded. The team designed the geometry so that a cylinder printed in the closed state snaps to an expanded state when a threshold tensile load is applied. That snap-through event is the key mechanical behavior.

Variables like cell shape, wall thickness, and cylinder diameter let the team tune the snap-through force and energy absorption for specific use cases. Larger diameters require more force to transition. Thicker walls resist deformation longer. By varying those parameters across three tested cylinder sizes, the study showed predictable, diameter-dependent stiffness scaling.

Co-axial stacking adds another programmable layer. Nesting two or three cylinders of different sizes inside each other produces assemblies that collapse in sequence: the outer cylinder resists, then the middle, then the inner. The team demonstrated soft-medium-hard collapse responses from the same basic design. That staged energy absorption is the property that makes the approach interesting for protective equipment.

What it could be used for

The study lists several target applications: passive mechanical clutches, vibration bandgap absorbers, soft actuators, wearable assistive devices, and impact protection systems. Helmet liners are a natural fit. A helmet liner built from stacked kirigami cylinders could absorb low-speed impacts softly, then stiffen under higher forces, all without electronics or sensors. Shock absorbers for bikes or vehicles are another obvious use case: geometry replaces material.

The open-access paper, simulation workflow, and rotary G-code approach mean the design process is replicable. The researchers released the G-code generation method in the paper. That lowers the barrier for other groups to adapt the approach to different materials and geometries without starting from scratch.

There are limits. The design logic for the kirigami patterns and stability landscapes is not trivial. Predicting how geometry, wall thickness, and material properties interact over the full loading cycle requires simulation. The team used a simulation-driven design workflow for that reason. Getting the behavior right without the simulation step would be difficult.

Why this matters for desktop makers

What stands out about this work is that it uses a commercially available rotary module on a machine that many home users already own. The Snapmaker 2.0 A350 is not an industrial system. The TPU filament is standard. The slicing workflow is accessible. If the kirigami design logic becomes easier to work with, rotary printing could move from research labs to home workshops.

The study establishes rotary-printed, multistable meta-cylinders as a reusable platform. The same printing approach works across cylinder sizes, materials, and cell geometries. That modularity is the point: you are not designing a one-off part, you are designing a part family where geometry encodes mechanical behavior.