3D Printing Prosthetics

Prosthetics have become an increasingly popular field in the past decade, especially with the advent of 3D printing. This class, BADM 395 Digital Making, has provided students the tools and knowledge to understand the process of producing prosthetics. The process is fairly simple, but the results are revolutionary. The first step would be to utilize a CAD (computer-aided design) software. Such software is mainly based on geometric shapes and structures, thus prosthetics in particular can be designed through freeform and sculpting tools to structure the design to each unique individual. Fusion 360 by Autodesk includes freeform models and mesh modeling, both of which creates custom designs that conform to the surface of a human’s skin. After creating a base shape, Fusion 360 allows the user to use existing geometry to create forms using T-Splines. T-Splines can form curves and surfaces specifically towards a unique surface, and also will allow the prosthetic and the surface to connect effortlessly.

Another skill we learned in BADM 396 was the use of scanning utilizing both the Sense Scanner and the Structure scanner compatible with the iPad located in the Illinois MakerLab. This process is called reverse engineering, by scanning the surface of an object and then programming it with CAD software. In terms of prosthetics, this would collect data directly from the source, instead of measuring it without precision. These scans are compatible with existing CAD software, and we used MeshMixer in our case. Meshmixer is another design tool that uses a different method of displaying surface resolution, which is through dynamic triangle-meshes. A triangle mesh is a group of triangles rather than software that reports individual triangles. This method is more efficient because the software does not have to process every corner of every individual triangle. Say, for a prosthetic hand, after the surface of the body is scanned, MeshMixer picks up this surface, and the user can design a connecting part.

After designing the piece in CAD software, actually 3D printing the prosthetic is the next step. The 3D printer used in the MakerLab are the Ultimaker and Ultimaker 2+. A “How-to-build-a-3D-printer” workshop was held at the BIF this semester, which broke down the parts of a sample Ultimaker 3D printer. The way a 3D printer works is that it has a design for every cross section, and it layers on the object until you receive an entire 3D piece. For prosthetics in particular, the filament is the most important part. The standard type of filament is PLA, which stands for polylactic acid, and it is compatible with the Ultimaker 3D printer. PLA is biodegradable and is generally quite easy to work with.

A newer type of filament called NinjaFlex is made from thermoplastic polyurethane. For example, the “Knick Finger” is a 3D printed partial finger replacement. Nick Brookins, an engineer at Akamai Technologies, suffered from an accident that left him with an amputated finger. The e-NABLE community, those who collaborate to make 3D printed hands free, inspired him to produce a prosthetic finger for himself. Ultimately, this add-on to his hand has become to be very beneficial and easy to use on a daily basis. Many a times, amputees possess a certain mindset where there is PTSD and pain around the area where they were injured. Prosthetics can protect these areas and it is mentally calming as well.

Conventional prosthetics are often ill-fitting and are not comfortable for the user. 3D printed prosthetics allows for a much cheaper and more comfortable option. The conventional prosthetics process begins with a mold from plaster which makes the cast. This material is very uncomfortable and also does not have a nice smell. All in all, 3D printed prosthetics are a much better option, but the main con that is present is that it is not yet popular and accessible to all. But, technology always progresses with time, and always pushes the next boundaries.



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