If you break open a chicken bone, you won’t find a solid mass of white material inside. Instead, you will see a complex, spongelike network of tiny struts and pillars, and a lot of empty space.
It looks fragile, yet that internal structure allows a bird’s wing to withstand high winds while remaining light enough for flight. Nature rarely builds with solid blocks. Instead, it builds with clever, porous patterns to maximize strength while minimizing weight.
Cross-section of the bone of a bird’s skull: Holes keep the material light enough that the bird can fly, but it’s still sturdy.
Steve Gschmeissner/Science Photo Library via Getty Images
Human engineers have always envied this efficiency. You can see it in the hexagonal perfection of a honeycomb, which uses the least amount of wax to store the most honey, and in the internal spiraling architecture of seashells that resist crushing pressures.
For centuries, however, manufacturing limitations meant engineers couldn’t easily copy these natural designs. Traditional manufacturing has usually been subtractive, meaning it starts with a heavy block of metal that is carved down, or formative, which entails pouring liquid plastic into a mold. Neither method can easily create complex, spongelike interiors hidden inside a solid shell.
If engineers wanted to make a part stronger, they generally had to make it thicker and heavier. This approach is often inefficient, wastes material and results in heavier products that require more energy to transport.
I am a mechanical engineer and associate professor at the University of Wisconsin-Stout, where I research the intersection of advanced manufacturing and biology. For several years, my work has focused on using additive manufacturing to create materials that, like a bird’s wing, are both incredibly light and capable of handling intense physical stress. While these “holey” designs have existed in nature for millions of years, it is only recently that 3D printing has made it possible for us to replicate them in the lab.
The invisible architecture
That paradigm changed with the maturation of additive manufacturing, commonly known as 3D printing, when it evolved from a niche prototyping tool into a robust industrial force. While the technology was first patented in the 1980s, it truly took off over the past decade as it became capable of producing end-use parts for high-stakes industries like aerospace and health care.
3D printing makes it far easier to manufacture lightweight, hole-filled materials.
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Instead of cutting away material, printers build objects layer by layer, depositing plastic or metal powder only exactly where it’s needed based on a digital file. This technology unlocked a new frontier in materials science focused on mesostructures.
A mesostructure represents the in-between scale. It is not the microscopic…
