One pair for life? How 3D-printed shoes will change the way we walk

There is no doubt that 3D printing is creeping into everyday life. Housing, medical supplies, mobile phones and jewellery all make used of the technology. It is also becoming commonplace in the development of fashion and recently a company based in California called LuxCreo Lab – an incubator for innovation and ideas that utilise 3D printing – has sought crowdfunding for its latest initiative, a shoe called the Bisca360. This latest venture uses a fabric upper (the part that covers the top of the foot) attached to a 3D-printed mid-sole (the part between the bottom of the foot and the sole of the shoe). The use of 3D printing, it turns out, is hardly new in shoemaking, and has been routinely used to create prototypes for years. Adidas, in particular, first adopted the technology in 2002. Allowing for the creation of one-offs quickly, the technique is ideal for prototyping. However, the physical restrictions of the technology and machines have meant scaling things up to a commercial scale has been fraught with difficulties. Although limited to small-scale production, major shoe companies have used 3D printing to create individual pairs of custom-fit trainers for elite athletes. At the 2016 Rio Olympics, Adidas gave its then-revolutionary (and unreleased) Futurecraft 4D trainers, featuring a 3D-printed mid-sole, to medal winners as a gift. In all black, the laces were accented in either gold, silver or bronze to match the medal. In January 2018, Adidas collaborated with a California start-up Carbon to launch the same Futurecraft 4D on a commercial scale. It sold out immediately. Fuelled by a desire to bring 3D printing to the mass market, Adidas applied the same technology to its Y-3 Runner 4D, and Alphaedge 4D shoes. Last year, the company felt confident enough about its capability to introduce a 3D-printed mid-sole to the existing Boost trainer. With the Boost selling an estimated 50 million pairs per year, it marked a huge step forward in 3D printing scalability. Another company to try and tackle this has been the Boston-based New Balance. It announced an exclusive partnership with 3D printer manufacturer Formlabs in 2017, to create custom, lightweight shoe components. Focusing on sufficient cushioning for the forefoot (used to push off from the floor for each step), together they created a new material called Rebound Resin, named for its resilience and springy construction. In 2019, New Balance revamped its 990 Sport using this new technology, and used its upgraded iteration for the chewy-titled FuelCell Echo Triple shoe. In July, LuxCreo arrived, touting its Bisca360 shoe with an entirely 3D-printed mid-sole. Looking like a cross between a comfy office shoe and a trainer, the Bisca360 has many selling points. It is breathable, allowing air to circulate through the shoe. It is said to be 100 per cent waterproof through the use of nano-layered fabric, and it is made to order, so drastically reduces wastage. However, from a technical perspective, its most interesting feature is that its 3D-printed mid-sole is said not compress with usage. Whether made from standard-use injection-moulded ethylene vinyl acetate, or state-of-the-art lattice 3D printing, the force we put on the mid-sole with every step is vast. As the weight of the person makes impact with the floor, how the shoe absorbs and spreads that weight becomes critical. In effect, the mid-sole is the shock absorber of footwear, helping to dissipate the enormous forces at play. The weight of a step is measured in either pascals (Pa) or pounds per square inch (psi). A shoe with a large surface area, such as a snowshoe, spreads that weight over a large surface and will give a reading of 0.5psi. A stiletto heel, in comparison, compacts the weight to a single point, and gives a reading of 471psi. When moving or running is taken into account, these numbers increase rapidly. A report by sports company Saucony revealed that a force equivalent to three times body weight is exerted on to the foot when running, while other movements, such as jumping, can increase that by up to seven times body weight. Little wonder then that professional athletes and sports players pay close attention to their footwear. For the makers of the Bisca360 to say that its mid-sole cushioning will not degrade from the first step to the one millionth is a big statement to make. If true, this means LuxCreo has found a way of strengthening the materials used for 3D printing – most commonly ABS plastics, but also polyamide (nylon), glass-filled polyamide, epoxy resins, photopolymers and polycarbonate – so that springiness never declines. Using Light Enabled Additive Production, the company says its mid-sole “continually maintains its support structure, while providing maximum comfort”. Standard mid-soles are made using injection-moulded ethylene vinyl acetate, which, while cheap and effective, will begin to compress with heavy usage. If a glance at the back of your trainers reveals a slope to one side, mid-sole compression is partly to blame. No one stands perfectly all the time, and the rolling of the ankle inwards, known as flat feet or overpronation, or outwards, called supination, can have serious implications for the body as a whole. This is especially true for those who play a lot of sport, or go running. A good-quality sports shoe is designed to support the foot through a range of movements. If the wearer tends to always land on the outside of the foot when playing basketball, a good mid-sole will help protect and cushion that. If, however, the mid-sole begins to compress at that point, support is lost and it’s probably time for a new pair of shoes. In 2016 Reebok announced its own plans, with a partnership with BASF to develop a new concept called the Liquid Factory. Aimed at replacing traditional moulding techniques with 3D printing, that same year it created 300 limited-edition shoes with 3D-printed outsoles. Then it created the Liquid Speed shoe using specially developed urethane-based liquid that Reebok says is the “first-ever energy-return outsole, which performs dramatically better than a typical rubber outsole”. In 2018, it also created the Liquid Floatride Run, which for the first time applied 3D printing technology to the lacing, replacing them with a printed structure. The result is a slip-on shoe that stretches to fit, before retracting to the original shape. And its not only sports shoes that are embracing 3D printing. In 2013, Lucy Beard founded Feetz, an app that allows customers to take a scan of their feet, send it to Feetz, and seven days later, a pair of custom-fit, 3D-printed shoes arrive. As no two feet are the same, Feetz creates perfectly fitted shoes, which are 3D-printed, making them affordable and fast to produce. So promising is the brand, it now has ex-Reebok chief executive Uli Becker on its board of directors. At the more conceptual end is United Nude, a shoe brand founded in 2003 by Rem D Koolhaas. Inhabiting the space where architecture meets footwear, it teamed up with designer Iris Van Herpen in 2013 to create the shoes for one of her runway shows. It also worked with fashion designer Issey Miyake, as well as the late architect Zaha Hadid, on limited-edition chrome-covered shoes. In 2014, it created the Float shoe that could be printed at home using a cube 3D printer. Now stocked across the world (including at The Dubai Mall’s Level Shoes), it offers customers the opportunity to see their shoes being 3D-printed in front of them in-store.

One pair for life? How 3D-printed shoes will change the way we walk

The technology has been making strides in the world of footwear