Device Fabrication Evolves
The advancement of 3D printing within the orthotic and prosthetic industry is raising the standard for how devices are fabricated. Historically, all O&P devices started as a plaster model which plastics of differing densities and carbon fiber were draped over to create the final product. While this not only creates a large amount of material waste, it is also a time-consuming process which cannot be precisely replicated in the future for the same device.
Types of 3D Printing
Many levels of 3D printing exist for hobbyists to professionals through use of Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), and Multi-Jet Fusion printing (MJF). FDM is best thought of as a hot glue gun, melting the material in a specific pattern, adding layers upon itself creating the final product. This type of 3D printing, while most simple and cost efficient, is difficult to use in orthotics and prosthetics due to the tri-planar forces acting on the device. The different layers have a greater chance to separate, potentially causing the orthotic or prosthetic device to fail.
SLS 3D printers start as a powder material which is swept over a printer bed in a very thin layer, just over the thickness of a human hair. A CO2 laser then binds the powder on the surface in a very precise design. As these thin layers are built upon each other, they create a strong bond which prevents the separation of layers. Similar to SLS printing, MJF 3D printing is a powder-based printer which builds 0.8mm layers upon each other to produce the final device. Instead of a laser, MJF 3D technology uses an adhesive which binds the powder together. This adhesive is partially cured with UV light and then continually cured as more layers are added creating excellent adhesion as if the material had always been one piece. At Tillges, we primarily use MJF 3D printing technology for the production of our devices because of the long-term capabilities and repeatability of the printed parts.
How does the field of Orthotics and Prosthetics Benefit from 3D Printing?
While this new technology is fascinating, a common question is if the orthotic & prosthetic field needs to use 3D printing or if the field should continue with traditional fabrication techniques? 3D printing is part of the manufacturing field recognized as additive manufacturing which means the device is built from the ground up without excess waste compared to subtractive manufacturing, where a large block of material is carved to produce the final product. While O&P devices generally do not start as a large block of material, traditional techniques require the use of plaster models upon which plastic or carbon fiber is draped. The final design then needs to be cut out of the plastic and smoothed to create the final product. The 3D printed parts require minimal finishing touches that need to be performed once out of the printer and can be done in batches, freeing up more technicians to work on devices which need individual attention. Utilizing a 3D printing system creates a much more productive fabrication lab as multiple parts or devices can be printed and finished at the same time.
These 3D printers print materials of varying properties from rigid to flexible and the complex designs allow for differing thicknesses to increase the range of these properties as well. At Tillges, we print both flexible and rigid materials to meet the needs of our patients. Through the CAD/CAM process, the designs are specifically tailored to meet each individual’s specific anatomy and structural needs. When a clinician requests a specific device to be made, the CAD/CAM process adjusts the digital model to accommodate a patients’ bony prominences while applying pressure in specific areas as needed. If there are any issues with the fit of the device or an individual needs an exact duplicate, the digital file can be modified or re-printed as is. The accuracy of our CAD/CAM software in addition to the 3D printer creates a new standard for accuracy, repeatability and adjustability essential for our patients.
What to Expect from 3D Printing in Orthotics and Prosthetics at Tillges?
The way we have been utilizing 3D printing here at Tillges is just the beginning. The orthotics & prosthetics field is centered around finding new solutions to best help our patients maintain or regain their function in the most efficient and comfortable way possible. As this technology continues to advance and new problems present themselves on a prosthesis or orthosis, you can expect to see custom solutions tailored to fit individual needs. New designs are constantly being tested along with ideas of how to customize the devices. At your next appointment at Tillges, be sure to ask to see our 3D printing room and how we might be using the printers for your specific device.
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RESOURCES
- Fig. 1 Retrieved 10/5/2023 from:
- https://formlabs.com/blog/3d-printed-insoles/
- Fig. 2 Retrieved 10/2/2023 from: https://dozuki.umd.edu/Wiki/Introduction_to_Fused_Deposition_Modeling_%28FDM%29
- Fig 3 Retrieved 10/2/2023 from:
- https://www.hongkiat.com/blog/things-know-buying-3d-printer/
- Fig 4 Retrieved 10/2/2023 from: https://electroloom.com/binder-jetting-3d-printing-technology/
- Fig 5 Retrieved 10/2/2023 from: https://forerunner3d.com/wp-content/uploads/2018/07/HP-Multi-Jet-Fusion-High-Speed-Production.gif
- Fig 5 Retrieved 10/5/2023 from: https://livingwithamplitude.com/prosthetic-leg-covers-fashion-alternative-options/
- Fig 6 Retrieved 10/5/2023 from: https://www.npdevices.com/product/pipdriver/