For athletes trying to run fast, the proper shoe can be essential to achieving peak performance. For athletes trying to run as fast as humanly possible, a runner's shoe can also become a work of individually customized engineering.
This is why Adidas has married 3D printing with robotic automation in a mass-market footwear project it's called Futurecraft.Strung, expected to be available for purchase as soon as later this year. Using a customized, 3D-printed sole, a Futurecraft.Strung manufacturing robot can place some 2,000 threads from up to 10 different sneaker yarns in one upper section of the shoe.
Skylar Tibbits, founder and co-director of the Self-Assembly Lab and associate professor in MIT's Department of Architecture, says that because of its small scale, footwear has been an area of focus for 3D printing and additive manufacturing, which involves adding material bit by bit.
“There are really interesting complex geometry problems," he says. “It's pretty well suited."
Beginning with a 3D-printed sole, Adidas robots weave together some 2000 threads from up to 10 different sneaker yarns to make one Futurecraft.Strung shoe—expected on the marketplace later this year or sometime in 2022.Photo: Adidas
Adidas began working on the Futurecraft.Strung project in 2016. Then two years later, Adidas Futurecraft, the company's innovation incubator, began collaborating with digital design studio Kram/Weisshaar. In less than a year the team built the software and hardware for the upper part of the shoe, called Strung uppers.
“Most 3D printing in the footwear space has been focused on the midsole or outsole, like the bottom of the shoe," Tibbits explains. But now, he says, Adidas is bringing robotics and a threaded design to the upper part of the shoe. The company bases its Futurecraft.Strung design on high-resolution scans of how runners' feet move as they travel.
This more flexible design can benefit athletes in multiple sports, according to an Adidas blog post. It will be able to use motion capture of an athlete's foot and feedback from the athlete to make the design specific to the athlete's specific gait. Adidas customizes the weaving of the shoe's “fabric" (really more like an elaborate woven string figure, a cat's cradle to fit the foot) to achieve a close and comfortable fit, the company says.
What they call their “4D sole" consists of a design combining 3D printing with materials that can change their shape and properties over time. In fact, Tibbits coined the term 4D printing to describe this process in 2013. The company takes customized data from the Adidas Athlete Intelligence Engine to make the shoe, according to Kram/Weisshaar's website.
Closeup of the weaving process behind a Futurecraft.Strung shoePhoto: Adidas
“With Strung for the first time, we can program single threads in any direction, where each thread has a different property or strength," Fionn Corcoran-Tadd, an innovation designer at Adidas' Futurecraft lab, said in a company video. Each thread serves a purpose, the video noted. “This is like customized string art for your feet," Tibbits says.
Although the robotics technology the company uses has been around for many years, what Adidas's robotic weavers can achieve with thread is a matter of elaborate geometry. “It's more just like a really elegant way to build up material combining robotics and the fibers and yarns into these intricate and complex patterns," he says.
Robots can of course create patterns with more precision than if someone wound it by hand, as well as rapidly and reliably changing the yarn and color of the fabric pattern. Adidas says it can make a single upper in 45 minutes and a pair of sneakers in 1 hour and 30 minutes. It plans to reduce this time down to minutes in the months ahead, the company said.
An Adidas spokesperson says sneakers incorporating the Futurecraft.Strung uppers design are a prototype, but the company plans to bring a Strung shoe to market in late 2021 or 2022. However, Adidas Futurecraft sneakers are currently available with a 3D-printed midsole.
Adidas plans to continue gathering data from athletes to customize the uppers of sneakers. “We're building up a library of knowledge and it will get more interesting as we aggregate data of testing and from different athletes and sports," the Adidas Futurecraft team writes in a blog post. “The more we understand about how data can become design code, the more we can take that and apply it to new Strung textiles. It's a continuous evolution."
This article appears in the May 2021 print issue as “When Footwear Becomes Footware.”