Composites and Prostheses: Changing the World for the Better

It was 1981 when a research paper highlighted the work being done at Chailey Heritage Marine Hospital in Sussex, England. The research paper focused on how the hospital was engineering new prostheses using composite materials including carbon fiber reinforced plastics (CFRP) and aluminum alloys. Some 38 years later, composites and prosthetic devices are still changing the world for the better.

Back in 1981 it was not uncommon for prosthesis makers to run into trouble with CFRPs. Utilizing carbon fiber to build prosthetic arms, legs, and feet was fairly new. Fitting and using prostheses wasn’t easy either. But designers and medical professionals kept working to make things better. The state-of-the-art prosthesis of today is exponentially better.

Carbon Fiber Prepreg Technology

One of the more exciting developments in recent years is the introduction of carbon fiber prepregs. A prepreg is a carbon fiber fabric that arrives at the fabricator’s facility already impregnated with epoxy resin. It can be used to create a variety of parts.

Prepregs are preferred for certain applications where precision and consistency are non-negotiable. Prosthesis fabrication is one such area. Prosthetic devices have to be extremely precise if they are to offer maximum benefit to users. Nothing can be left to chance, especially given that the finished product may be the only prosthetic used by the recipient.

The two biggest advantages are observed in weight and flexibility. We already know that carbon fiber is more durable and stronger than aluminum, but it is also half the weight. It can be made more flexible with the right engineering processes. This is important because prosthetic devices have to be able to absorb shock sufficiently enough that they do not cause pain to wearers.

Combining Multiple Materials

It is worth noting that carbon fiber is not the only material being used by prostheses manufacturers. In many cases, they are combining carbon fiber with glass fiber and metal alloys to create customized devices for each wearer.

For example, you may have a prosthetic leg constructed mainly of carbon fiber attached to a foot that combines glass fiber and titanium. Combining the three materials keeps weight in check, offers considerable strength and durability, and allows for the kind of flexibility and movement observed in a natural ankle joint. You end up with a very usable prosthetic rather than just a cosmetic one.

Creating the Perfect Fit

For designers, the biggest challenge in building prosthetic devices is creating the perfect fit. People who wear and use them want to be comfortable. If a device is too uncomfortable to use, they simply will not use it. Then what’s the point?

Creating the perfect fit is all about customization. This is where some of the latest carbon fiber technologies come into play, explains Salt Lake City’s Rock West Composites. Technologies like carbon fiber prepregs and 3D printing are making an enormous difference.

Creating prostheses by way of 3D printing appears to be the trend of the future. The 3D printing process allows for extreme customization with very tight tolerances. Finished parts generally do not have to be machined either, which is big. As long as the prototype fits comfortably, a manufacturer can proceed with the primary part. Once done, that prostheses will be ready to go with very little extra effort.

Medical science has come a long way over the last 30+ years. Prosthetic devices and composites, when combined together, completely change everything. Modern protheses are giving people their lives back. They are fulfilling the dreams of first-generation designers who knew that prostheses would one day be what they are today.

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