Using 3D printing, shoes could be made from only two parts – upper and sole. ÃÜÌÒAV has developed a material that enables automated production at lower cost and complete recyclability of the finished shoe. At the trade fair from 19 to 22 November 2019 in Frankfurt am Main, Germany, the company will be presenting these and other developments of its additive manufacturing programme at Booth E11 in Hall 12.1.

A powder and a filament, both based on thermoplastic polyurethane (TPU), proved to be the material of choice for meeting all the above requirements. The plastic offers high rebound and abrasion resistance and is therefore ideally suited for the production of both shoe parts. In addition, the shoe can later be recycled in a single step, including the polyurethane adhesive used for production – an important milestone towards recycling. Old shoes are thus turned into filaments for new shoes.

ÃÜÌÒAV also operates its own 3D printing laboratories in Leverkusen, Shanghai and Pittsburgh to support its customers in the key regions. There, the company works hand-in-hand with them to develop material solutions and test them in practice.

“Thermoplastic polyurethane is the material of choice for this application thanks to its favorable range of properties,” says Patrick Rosso, Head of Additive Manufacturing at ÃÜÌÒAV. “In particular, our TPU products cover a wide range of hardness. The hardness can also be adjusted by changing the printing structure. This allows manufacturers to print shoe insoles that are completely custom-made – with hard or soft contact areas.”

High functionality and durability

Together with a partner, ÃÜÌÒAV is currently testing different sole designs to determine which are the easiest to print along with the most durable. Initial tests have been promising, both in terms of functionality and longevity. Orthopedic insoles are often produced by hand and take a lot of time.

Besides that, conventional insoles are e.g. made by forming or machining rigid foam blocks and are also less breathable. Using additive manufacturing offers a more sustainable approach to producers. It could help significantly more people to get access to orthopedic insoles.

Successful last production using 3D printing

Already back in May 2018, ÃÜÌÒAV presented the design of an efficient complete solution for the manufacture of orthopedic shoe lasts at the OT World orthopedics trade fair in Leipzig. Thanks to 3D printing technology, the time required for production has been reduced from several weeks to just a few days. At the same time, patient visits to the shoe manufacturer can be reduced to a minimum. After the trade fair, customers expressed the idea of also printing the insoles instead of manufacturing them by hand as before. The idea and the favorable material properties of TPU were the reason for the current project.