help with 3D print filaments for prosthetics

[DT_student 0]

Hello, I am a high schooler doing a conceptual prosthetic project for lower transradial amputees (below elbow amputations) in developing countries for their Year 12 D&T major work. the prosthetic part will not be a hand but a range of different attachment of tools that will most likely be applied in agricultural setting.

 

Ideally, I am looking for materials that make the prosthetic both more affordable and robust that uses FDM printing, so I did some research on some materials and found some existing solutions that use materials such as PLA and ABS for their designs.

 

As part of the documentation requirements, I need to get feedback from someone that could justify this choice of material or recommend another choice of material.

Thanks in advance! 🙂

[Benattar 1]

Hi.

In the university where i study we have printed prosthetics and we did find out PLA is quite  good option.

We also tried out with a "Solutech" filament made of PLA and Carbon Fiber wich is very resistant and its supossed to be lighter (We did not weight it hehe but it seems like its true).

But you need to keep in mind there are other factors beside the material. It also depends on  factors like ergonomy (gotta find a comfy material to use between the prosthetic and the amputed member and usability (we gotta know if the patient wil be up to use any color or if the design its cool for him/her).

Hope my answer helps you. Greetings!

[geert_2 557]

For strength, I think PLA would do if it is for just touching or picking up things, but maybe not for carrying a full body weight. But PLA is not temperature-resistant, so you can not leave it in the car in a sunny environment. Even not in moderate European springs and autumns. Don't ask how I know. :-)  In that case maybe PET could be a good choice, but print this with cooling fans off or very low for good layer bonding. ABS might not give enough layer bonding?

 

For comfortable attachment to the body, you could provide enough room around the connecting area, and then fill this with soft silicone paste. The same silicones that are used to make "wounds" and face masks in films: these are very soft and skin-safe. That would also absorb some shocks.

 

If the material has to be softer and more shock-absorbing, maybe nylon would be better?

 

Or make moulds by 3D-printing them, and then cast the body-part in softer materials? Or cast in a mix of soft and hard, like a nylon core, surrounded by soft silicone or soft polyurethane? Thus simulating bone and flesh? Use plenty of release spray for casting urethanes, because they glue like mad. Be sure to carefully sand the mould, so it is smooth. Otherwise the layer lines will make removal very difficult, and they will accumulate dirt and bacteria.

 

If it was for myself, I think I might prefer the moulding and casting method. Also, silicones can be autoclaved and desinfected: they are quite temperature resistant and chemically inert.