An X-Ray View of Lattices and String Lasting: The Cool Parts Show Bonus

In the most recent episode of The Cool Parts Show, Pete Zelinski and I discussed a pair of shoes manufactured by Hilos. These custom heels combine a traditional leather upper with a 3D printed TPU platform that replaces multiple layers of material with just one piece. Lattices in the footbed provide the cushioning in place of foam, and internal channels accommodate the “string lasting” mechanism that unites all the parts of the shoe. But most of this complexity is invisible from the outside. To get a better look, we sent the shoes to Creative Electron, a provider of X-ray systems and inspection software. See what they found in this special bonus update. | This episode of The Cool Parts Show brought to you by Carpenter Additive

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Related Resources

• Our full episode of The Cool Parts Show on Hilos
• More on Hilos’ vision for sustainable footwear
• Creative Electron

Transcript

Peter Zelinski

I'm Pete.

Stephanie Hendrixson

I'm Stephanie. And this is a special update to The Cool Parts Show. So Pete, we just recently did an episode about Hilos, the custom recyclable heels with the 3D printed platform. Could you maybe just recap some of the high points there?

Peter Zelinski

Sure. Hilos, women's shoes, 3D printed, a couple things going on. One is lattices inside the structure of the lower part of the shoe. The lattices mechanically provide the cushioning, so there doesn't have to be padding, that's part of an assembly. So that lower part is just one piece 3D printed. And then the upper part is leather, like you'd expect, but the 3D printing helps there too, because passages inside that lower part, allow the upper to be held on with strings. String lasting was their term for it. No glue means it's easy to disassemble. Meaning when the wearers are done with the shoe, they send it back to Hilos, Hilos takes it apart, all those materials can be reused.

Stephanie Hendrixson

Right. And so we had the shoes here in the studio with us, we talked about a lot of those things. But a lot of the really interesting design elements, the lattice and the string lasting, were on the inside. Things that we couldn't actually see while we had the shoes here in the studio. Would you like to see what the inside of those shoes looks like?

Peter Zelinski

So do we have X-ray footage?

Stephanie Hendrixson

We have X-ray footage!

Peter Zelinski

I want to see.

Stephanie Hendrixson
So I sent the shoes out to Creative Electron. They're a company in California that develops X-ray systems and software for inspection. They scanned the shoes for us. And they sent us back some video and some photos of what they found.

Peter Zelinski

Okay, so I can see the lattices on the inside the 3D printed forms, I can see the string lasting in there too, the string. Does that look the way you expected it to look?

Stephanie Hendrixson

No, it doesn't. So we talk all the time about how 3D printing enables all of this complexity and like you sort of get that out of the lattice there. But when I first learned about string lasting and 3D printing together, I was picturing like this zigzagging string like running all the way through the shoes. And the fact that it's just like this one, figure eight. It's so like startlingly simple.

Peter Zelinski

Right? So thank you for saying that. Like that's what I was expecting, too. We talk about 3D printing enabling internal complexity all the time, and I expected some kind of complex thing and it's just that figure-eight bolo tie. It is a simpler and more elegant design than I had thought.

Stephanie Hendrixson

Yeah. And so it's a functional design. It lets the shoe do what it needs to do. It also makes that disassembly process, that recycling process much easier. So thank you again to Creative Electron for doing the scan, providing this footage and to Hilos for sharing the shoes with us. We'll see you next time on The Cool Parts Show.