Practical Prosthetics: How HKK Bionics Harnesses Additive Manufacturing to Empower Users

HKK BIONICS

At HKK Bionics, their slogan, “Empowering Motion,” truly captures the essence of what they do. This innovative start-up, founded in May 2017 by Dominik Hepp and Tobias Knobloch in Ulm, Germany, is on a mission to help people with paralyzed hands regain their gripping function through cutting-edge bionic hand orthosis.

Their motivation is deeply personal. Dominik Hepp, for instance, faced limited hand mobility after a car accident left him with multiple injuries, including to both hands. It was during his studies in medical engineering at the Ulm University of Applied Science that he and his co-founder, Tobias Knobloch, developed the idea for this revolutionary product.

By blending traditional orthopaedic craftsmanship with groundbreaking technology, innovative concepts, and state-of-the-art manufacturing, they created the Exomotion Hand One. This high-tech orthosis provides people with mobility restrictions not just freedom of movement, but a whole new level of quality of life. With intuitive control, preset grip functions, and a combination of intelligent software and muscle impulses, the Exomotion Hand One is transforming lives, empowering users to move forward with confidence.

The Challenge

Creating the Exomotion Hand One required precision engineering at every level. With over 40 individual components, each designed to interlock seamlessly, HKK Bionics needed a solution that combined accuracy, durability, and consistency.

The motorised glove with a splint is made up of multiple elements, including exo-mechanics, artificial tendons, a splint, a silicone glove, a display, and sensors—many of which were produced using industrial Selective Laser Sintering (SLS) additive manufacturing. However, achieving the right quality for a functional, patient-ready product came with significant challenges.

High Standards, Complex Requirements

• Each polyamide component required exceptional precision to ensure a perfect fit.
• Raw additive manufactured parts had a rough surface and inconsistent colouring, making them unsuitable for final use.
• Every component needed homogeneous surface finishing and colouring while meeting strict medical standards, including cytotoxicity and skin irritation tests.
• The final product had to be lightweight, comfortable, and fully customised, all while remaining cost-effective, even for single-unit production.

From the outset, it was clear that only industrial additive manufacturing could meet these demands. With unmatched accuracy and scalability, SLS technology provided the perfect foundation for HKK Bionics to push the boundaries of innovation—turning a visionary idea into a life-changing solution.

The Solution

Precision finishing and customised aesthetics

Transforming raw additive manufactured components into a functional, high-quality medical device required an advanced finishing process. The Exomotion Hand One demanded homogeneous surfaces, durable materials, and precise colour matching—all while maintaining the highest medical standards.

By leveraging industrial additive manufacturing alongside specialist surface treatment and colouring processes, HKK Bionics ensured that every part met strict safety, durability, and aesthetic requirements. This allowed for:

• Seamless patient customisation – Each orthosis begins with a 3D scan, ensuring a perfect anatomical fit.
• Consistent part quality – Every component undergoes controlled surface finishing and colour matching, making it both functional and visually seamless.
• Future-ready innovation – The potential to personalise the final colour to match skin tones or patient preferences, enhancing both confidence and usability.

By combining cutting-edge additive manufacturing with advanced post-processing, HKK Bionics is redefining what’s possible—delivering custom-fit, high-performance orthotic solutions that empower motion.

Print-to-Product Workflow

1. Cleaning (10 min)
   Once the parts are produced, they undergo an initial powder removal process to ensure a clean surface for finishing.
2. Surfacing (10 min)
   Next, they are treated with an advanced surfacing process that enhances durability, scratch resistance, and provides a smooth, matte-gloss finish—ideal for daily use.
3. Colouring (2.5 hours)
   Finally, the parts undergo a deep-dye colouring process, ensuring a consistent, high-quality finish. Just 5 hours later, the components are fully finished and ready for assembly.

By leveraging high-precision additive manufacturing and tailored post-processing, HKK Bionics delivers a seamless blend of form, function, and aesthetics, empowering users with medical-grade innovation.

The Benefits

1. Certified for Safety & Biocompatibility
   Biocompatibility is essential for any medical device in contact with the skin. The DyeMansion colours used in the Exomotion Hand One have passed rigorous Cytotoxicity tests (ISO 10993-5, 10993-12) and Skin Irritation tests (ISO protocol TC 194 WG 8, ISO 10993-12) to ensure the highest standards of safety and skin compatibility.
2. Precision Colour Matching & Customisation for Greater Acceptance
   The more discreet and personalised the orthosis, the more readily it is accepted by patients. Using spectrophotometry and multiple iterations, the colour matching process ensures the orthosis is tailored to each patient’s unique needs. With a choice of skin tones and a wide range of colours—including Pantone, RAL, and custom shades—patients can choose the perfect match for their skin tone or personal preference, enhancing the comfort and acceptance of the device.
3. Improved & Homogenous Haptics
   Comfort is key for wearables. The PolyShot Surfacing (PSS) process delivers a consistent, smooth surface that not only ensures comfortable wear but also enhances durability without compromising part geometry. This treatment also helps to achieve consistent dyeing across all parts, ensuring a uniform finish.
4. Tailored, Individual Products
   Each orthosis is custom-designed to meet the unique needs of the patient. Using additive manufacturing and the Print-to-Product workflow, HKK Bionics can produce individualised solutions economically, even in small batch quantities, ensuring the highest quality with a personalised approach.

Conclusion

If you’d like to learn how LPE can support your needs with advanced 3D printing solutions, please don’t hesitate to get in touch. Our team is ready to help turn your ideas into life-changing innovations.

A special thank you to DyeMansion for providing the insightful case study, and to HKK Bionics for their innovative approach to advancing medical solutions. Their work is truly shaping the future of orthotic care.