The First Fully 3D-Printed Orthopaedic Shoe Worn at OTWorld in Leipzig

Additive Manufacturing with Ultrafuse® TPU

This is where 3D printing steps in as a true innovation. Unlike traditional orthopaedic shoe making methods, 3D printing automates the entire production process, and enables a fully integrated digital workflow. This reimagines the design and production of medical footwear from the ground up.

Daniel Petcu, a footwear engineer with a PhD in foot orthoses, recognized the potential of 3D printing early on. After experimenting with a Prusa MK3S printer, he decided to shift his company, Pedorthic Art, to focus exclusively on 3D printing. This decision was driven by the advantages offered by Fused Filament Fabrication (FFF) 3D printing, particularly the automation of the manufacturing process and the unparalleled design flexibility it enables.

With 3D printing, new design options become possible, including the use of metamaterials – internal structures with properties that traditional methods simply cannot achieve.

Inspired by The Perfect-Fit Climbing Shoe, Daniel designed and produced the first fully 3D-printed orthopaedic footwear, which he wore at OTWorld in Leipzig. Flexible 3D printing materials like Ultrafuse® TPU 85A and TPU 64D were ideal choices for the application, enabling fast printing, excellent abrasion resistance, and compliance with medical device safety regulations thanks to their biocompatibility.

Re-Imagining Orthopaedic Footwear Design and Production

The development of this fully 3D-printed orthopaedic shoe involved several key stages:

1. Pedorthic Information Modeling Concept

Using the Pedorthic Information Modeling (PIM) concept, which is based on parametric design principles, Daniel was able to manage the complex variations in design parameters effectively, ensuring that every aspect of the shoe met the specific needs of the patient.

2. Parametric Thinking and Design

Using custom-designed, algorithm-based CAD software like Rhino and Grasshopper, Daniel was able to create a highly detailed digital model of the shoe. This parametric and algorithm-based 3D modeling ensured that the final product would be both functional and aesthetically pleasing. It also meant that basic inputs could be adjusted to tailor the design to another patient, without the need to manually design an entirely new shoe.

3. Designing, Printing, and Testing

The shoe was designed as a single part, integrating both the upper and midsole into one cohesive unit. This design not only streamlined the manufacturing process but also enhanced the structural integrity of the shoe. A particular focus was placed on designing an ‘infill-based’ rocker bottom shoe, which is crucial for patients with specific conditions like bilateral ankle rigid equinus. The flexibility and durability of the shoe uppers, with a thickness of 5 mm, were thoroughly tested to ensure they met the necessary wearing comfort.

4. Leveraging Ultrafuse® TPU Materials

Ultrafuse® TPU 85A and TPU 64D were integral to the success of this project. These materials provided the perfect balance of flexibility and durability, essential for creating a shoe that could withstand daily wear while maintaining comfort. The biocompatibility of Ultrafuse® TPU ensured that the shoe was safe for prolonged contact with the skin, meeting stringent medical device regulations. They also could be 3D printed at above-average speeds, streamlining the production process.