Transforming Prosthetics and Orthoses Manufacturing with the EOS SLS Process

The fields of prosthetics and orthoses have witnessed significant advancements in recent years, driven by the adoption of additive manufacturing (AM) technologies. Among these, the EOS Selective Laser Sintering (SLS) process stands out as a transformative method, offering unmatched precision, customization, and efficiency. By leveraging the unique capabilities of SLS, manufacturers can create prosthetic and orthotic devices that enhance mobility, comfort, and quality of life for users.

The Need for Advanced Manufacturing in Prosthetics and Orthoses

Traditional manufacturing methods for prosthetics and orthoses often involve labour-intensive processes with limited customization. Patients’ unique anatomical needs and functional requirements can be challenging to address with these conventional techniques. Additive manufacturing, and specifically the EOS SLS process, addresses these limitations by enabling:

• Personalization: Tailoring designs to fit individual anatomy and specific functional requirements.
• Complex Geometries: Creating intricate structures such as lattice designs for lightweight yet strong components.
• Rapid Prototyping: Accelerating the design-to-manufacturing cycle for quicker delivery.
• Material Versatility: Using high-performance polymers that ensure durability and comfort.

Fig. 1: Conventional Manufacturing Workflow of AFO (Ankle – Foot – Orthosis)

How does the EOS SLS Process Works?

The EOS SLS process involves the use of a high-powered laser to selectively fuse polymer powder layer by layer, creating precise and durable parts. This technology eliminates the need for support structures, allowing for greater design freedom and efficient material usage. It is particularly well-suited for prosthetics and orthoses due to its ability to produce lightweight, robust, and anatomically accurate components.

Fig. 2: Digital Manufacturing Workflow of AFO (Ankle – Foot – Orthosis) | Courtesy – (EOS Website)

Materials for Prosthetics and Orthoses

EOS offers a range of materials that cater to the specific needs of prosthetic and orthotic devices:

• EOS PA 1101: A bio-based polyamide known for its elasticity, impact resistance, and durability, making it ideal for lightweight and flexible components.

Fig. 3: Bio – Based EOS PA 1101 carbon reduced material specifically designed for O & P applications

•  EOS PA 2200: A versatile material known for its strength, flexibility, and biocompatibility, making it ideal for components that come in contact, with the skin.

Fig. 4: Biocompatible EOS PA 2200 material widely used for O & P applications

Advantages of Additive Manufacturing for Orthoses and Prostheses

• Virtually limitless customization potential: Tailor designs for unique anatomical and functional needs, enabling unmatched personalization.
• Optimal comfort for the wearer: Lightweight and stable designs ensure comfort, even with complex structures.
• Sustainability: Minimized material consumption, with unused material being reusable, making the process eco-friendly.
• Quick adjustments: Easily implement modifications, such as accommodating growth in children.
• Enhanced functionality: Integrate features for elasticity, breathability, and other functional benefits to increase comfort.
• Fully digital workflow: From scanning to finished product, the streamlined process ensures faster availability.

Applications of SLS in Prosthetics and Orthoses

• Prosthetic Sockets: Precisely contoured sockets ensure a snug fit, enhancing user comfort and mobility.
• Orthotic Braces: Lightweight and durable braces provide optimal support and flexibility for various medical conditions.
• Limb Covers: Aesthetic covers with intricate designs allow users to personalize their prosthetic devices.
• Foot Orthoses: Customized insoles tailored to the patient’s unique foot structure for better support and alignment.

Fig. 5: Customer-specific Orthoses and Prostheses solutions | Courtesy – (EOS Website)

Success Stories

Manufacturers and clinicians using the EOS SLS process have reported significant improvements in patient satisfaction and device performance. For example, prosthetic sockets produced using SLS technology have demonstrated superior comfort and durability compared to traditionally manufactured counterparts. Additionally, the ability to rapidly prototype and iterate designs has reduced production times and costs.

The British start-up company Andiamo uses EOS systems to make custom-fitting orthoses for children. Traditionally, orthoses are made from plaster impressions. This process is slow and resource-intensive and offers little room for customization.

Some patients, especially young patients who are still growing, have to undergo this procedure repeatedly. Waiting times can last up to six months – for an orthosis that might not even fit by the time it’s ready. Additive manufacturing reduces the waiting period to a minimum. Using a 3D body scan, a precise and perfectly fitting orthosis is manufactured and delivered within a week.

Fig. 6: Foot and Upper Body Orthoses from Andiamo | Courtesy – (EOS Website)

The Future of Prosthetics and Orthoses Manufacturing

As additive manufacturing technologies continue to evolve, the possibilities for prosthetics and orthoses are expanding. Emerging materials, enhanced machine capabilities, and integration with advanced scanning and modelling software promise even greater levels of customization and performance.

By adopting the EOS SLS process, manufacturers can push the boundaries of what is possible in prosthetics and orthoses, delivering devices that not only meet but exceed the expectations of patients and healthcare providers. This technology is not just shaping parts; it’s reshaping lives.

Fig. 7: Different types of Ankle Foot Orthoses from Ottobock | Courtesy – (EOS Website)