The Making of a 3D Printed Rehabilitation Orthosis

With this 3D printed rehabilitation orthosis, a disabled man can perform physical activities. The prototype of the device was manufactured on ZMorph multitool 3D printer.

[UPDATE: Source files are now available for free download from Instructables]

Medical 3D printing has many applications in various fields. In orthotics, industrial 3D printers are used to manufacture custom-sized orthoses, braces as well as prosthesis and parts for powered exoskeletons. First two helps patients with broken bones while the latter are used for amputees. There’s still a lot of untapped potential for helping the patients with cases of mild and partial paresis who need lighter and more comfortable 3D printed rehabilitation orthosis which won’t harm their existing but weak extremities.

3D Printed Rehabilitation Orthosis - Hand
3D printed rehabilitation orthosis made with ZMorph multitool 3D printer

Eliza Wrobel faced this problem during her Biomedical Engineering studies under Bogdan Dybala, PhD. Eng. at the Faculty of Mechanical Engineering of the Wroclaw University of Technology. She was asked for help by a 33 years old man suffering from tetraplegia (the limb paresis) after being in an accident a few years back. He needed a light, yet durable orthosis that could help him grab objects during the rehabilitation and other physical activities as he couldn’t hold even the lightest dumbbells. In order to play his favorite table tennis, someone had to tie a paddle to his hand which wasn’t too comfortable.

Answering the needs

The 3D printed rehabilitation orthosis had to answer the patient’s needs which meant that Eliza has had to reverse engineer it. She started with making a plaster cast of the patient’s hand which was later filled with liquid ceramic mass and supported by a metal bar inside, so the model itself was easier to hold. After 24 hours, the hand’s model was grinded and then 3D scanned using the ATOS II machine available at the Wroclaw University of Technology.

Cross-section_of_patients_hand
Early design work for the rehabilitation orthosis

With a 3D model of the patient’s right hand ready, the actual designing of the orthosis have started. In CAD software Eliza tried different mechanical solutions for the rehabilitation device. The biggest challenge was to bring together both the device and the flesh. Solutions used in prosthetics could harm the man’s tissues while standard orthosis used for broken bones would keep his hand in only one setting – open or clenched.

#D Printed Rehabilitation Orthosis - 3D Design
3D model of the orthosis

The answer was found somewhere in between. The husk of the orthosis had to be closely fitted to the wrist, while the fingers were supported by smaller parts imitating their joint-structure – 2 joints for the thumb and 3 joints in every other finger. To connect these parts into a working device, Eliza added a series of lever mechanisms controlled by one big lever at the top of the husk. Pressing the main lever accelerated the hand grip while pulling it away returned the fingers to their rest state.

3D Printing of the design

The design of the rehabilitation orthosis consisted of over 70 different parts. They were all exported as STL files, checked for any shortcomings in Netfabb Basic and then imported to the Voxelizer software in order to prepare them for 3D printing. The parts for the orthosis were later 3D printed on ZMorph multitool 3D printer with single head extruder 1.75 mm using ABS filaments of different colors.

3D Printed Rehabilitation Orthosis - Voxelizer
Part of the orthosis in Voxelizer software

 

 

ZMorph’s precision and the quality of the prints allowed Eliza to minimize the number of non-printed parts in her device. Small 3D printed pins were used to connect the smaller leverages and finger casings to each other while the main lever was connected with the husk with a 3D printed latches. Velcro strap was added later in order to fasten the orthosis around patient’s hand.

3D Printed Rehabilitation Orthosis - 3D Print
3D printed rehabilitation orthosis made with ZMorph multitool 3D printer

What’s next for this 3D printed rehabilitation orthosis?

With the help of ZMorph multitool 3D printer, Eliza was able to quickly fabricate, improve and finalize a working prototype of her design. The desktop machine proved to be a quick, reliable and inexpensive alternative to outsourcing prototyping services based on industrial 3D printers. Thanks to the durability of ABS-based 3D parts printed on the ZMorph, the prototype can be used in a limited capacity by the patient during his physical activities.

3D Printed Rehabilitation Orthosis - 3D Prints
3D printed rehabilitation orthosis made with ZMorph multitool 3D printer

Further works on this student’s idea could soon result in a wide production of custom-made 3D printed rehabilitation orthosis for patients with a hand paresis and thus significantly improve their everyday life.

[UPDATE: Source files are now available for free download from Instructables]

Marcin Traczyk

Content Marketing Manager at ZMorph. 3D printing enthusiast and avid gamer

21 thoughts on “The Making of a 3D Printed Rehabilitation Orthosis”

  1. Is this design available open source for others to use to help others with a disability who need one? If so, where would one find the files?

    1. The author plans to share her design but please have in mind that the orthosis was designed with a specific man (and his hand) in mind, so it’s custom-made to fit him. Other people with similar disability can benefit from this project too but only if someone fit the design to their hands first.

  2. Yes, I was also wondering if the STL files can be shared on Pinshape or GrabCAD? This is some really good work that many people could benefit from.

    1. I know that the author plans to release her files but since the project is custom-made for a specific person, these files could be used only for 3D printing purposes and not for rehabilitation of other disabled people.

    1. This orthosis is custom made for a single person and hybrid 3D printer was the fastest way to work on it. Mostly because you can iterate and improve the project much faster – without the need for creating new molds every time. The result is a working prototype for which thermoplastic molding could be a way to manufacture the final product in the future.

  3. Dear Marcin,

    We understand the limitations of the current design as far as a targeted individual…. Still being able to examine the CAD diagrams would provide
    a tremendous learning opportunity. Releasing them to open source would greatly expand its development and utilization. Unless that’s not what you have
    in mind.

    Doc

    1. I totally agree with you, Doc Davies.

      The author of this prototype plans to release the files exactly for this – learning opportunities for other designers.

      I’ll let you know when the files are available online.

    1. ZMorph (and no other FDM 3D printer that we’re aware of) is not certified for toy manufacturing as child’s products are secured by many attestations, certifications, and quality restrictions. Our machine could be used to manufacture prototypes of toys but we don’t recommend manufacturing end products with it.

      We didn’t work with PETG filaments so far, so we’re not sure if it’s worth buying. We know that objects made from ABS filaments shouldn’t be given to children while PLA-made objects are completely safe.

      I hope this helps! 🙂

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