Marrying nature with mathematics has enabled the AMRC Design and Prototyping Group (DPG) to push the boundaries of new Additive Manufacturing (AM) technologies, cutting cost, manufacturing time and waste.

The initiative combines the way nature makes insect wings with fractal mathematics to remove the need for additional support when curved structures are built up from layers of plastic on a 3D printer, using The Fused Deposition Modeling (FDM) process.

Making curved shapes on a 3D printer often involves laying down support material which has to be cut away and disposed of at the end.

Printing the support material adds to the cost, slows the process down, generates waste and results in additional work to finish the component where the support has been cut away.

The DPG team decided to investigate ways of developing self-supporting printed structures as part of a continuing project to design and develop a fixed wing Unmanned Aerial Vehicle, or UAV.

Designers used fractal mathematics, which generates repeating patterns, to create an intricate internal structure for the wing, resembling that of an insect, where repeating patterns of veins strengthen the wing, while allowing its surface to remain flexible.

In the case of the UAV, designers used the fractal structure to replace separate strengthening ribs, used within the wing of an earlier prototype, and avoid the need for support material.

After researching fractal structures, the team decided on a tree-like structure with successive branches of different length splitting off at the same angle to left and right.

They developed an algorithm in the C# programming language to calculate the coordinates for the branches and used the data in the Catia CAD package, where they already had a design for the surface of the two layer wing.

The model was modified so that the angle between the two layers could be kept below 30