Lower Arm Prosthesis

This lower arm prosthesis was designed with the intention of making a low-cost prosthesis available to wider demographic. Often prostheses can be very expensive, making them inaccessible to people in need. The low cost of 3D printed parts provides a world of opportunity for accessible medical devices, and this redesigned lower arm prosthesis is intended to take advantage of this. That being said, it is important to note that this device is currently just a prototype and has not been thoroughly tested. This design is currently an interesting proof of concept, but is not intended to be used as a prosthesis in its current form.
This arm prosthesis consists of many different parts intended to be printed individually using an FDM printer. Most of the parts are intended to be printed with ABS plastic, using water-soluble supports to ensure accurate printing. The pins in this design should be printed with 100% infill to increase their strength, but this amount of infill is not required for the other parts. Several of the other parts are intended to be printed with a flexible polyurethane filament (such as NINJAFLEX). These flexible parts are highlighted in blue in the additional photos provided, and include the finger joints, flexible wrist, and upper arm band. Because the polyurethane filament has a shore hardness of only about 85A, it allows for the parts that are printed to flex freely. This allows for a comfortable upper arm band, as well as a moveable wrist and fingers. If this type of filament is unavailable, then these parts could be printed with ABS as well, it would just prevent the joints from being flexible.
To demonstrate the 3D printability of this design, the STL of the full arm assembly was uploaded to slicing software, and a screenshot was taken. The full arm assembly was just used as an example to demonstrate printability, the pieces are not actually intended to be printed this way, they are intended to be printed individually as described above. Some parts are repeated in the design, and therefore need to be printed more than once. Additionally, for the purposes of this submission, the parts of the forearm, wrist, arm band and connectors can be excluded so that the design meets the size requirement when the parts are printed separately.
This arm is intended to be used as an active prosthesis, meaning that motors can open and close the hand based on measured EMG signals from the user’s arm. The electronic components required for this are ...