Polyurethane makes 3D printed orthopedic insoles strong and flexible at the same time

In order to create a comfortable walking and running experience, orthopedic insoles need to be fully customized and breathable. They also have to be strong enough to support the foot and be flexible at the same time. Covestro and partners wanted to create a 3D printed orthopedic insole that combines all the positive properties this product needs.

Orthopedic insoles have to be mechanically strong and flexible at the same time. Depending on the customer, they have harder and softer spots. Covestro wanted to develop a printing material that fulfills exactly these needs.

Polyurethane has ideal mechanical properties for orthopedic insoles: It is adjustable from very tough to flexible and has outstanding weathering resistance. This material fulfills all the needs of 3D printed insoles. That’s why we developed Addigy® liquid PU resins and TPU powders for 3D printing. They can be processed using a DLP (digital light processing) printer or powder bed fusion and can be adjusted to the desired product properties of orthopedic insoles ranging from more flexible to more rigid. By changing the printed structure, the hardness of the insole can be adjusted. The printed structure also makes the insole highly breathable. This enables the shoe maker to design an insole that gives the right support for every patient. All in all, additive manufacturing offers a solution to print fully customized insoles in an automated process that significantly reduces waste while being affordable.