## 6 Advantages of Including 3D Printing in the Manufacture of Prostheses
### Ease of Distribution and Global Collaboration  
Three-dimensional printing has revolutionized global collaboration in the development of robotic prosthetics, allowing for digital designs to be freely shared on platforms such as Thingiverse and Cults3D (Figure 7). This accessibility has fostered a collaborative environment where communities of developers, researchers, and clinicians can collectively enhance prosthetic designs, adapting them to meet specific patient needs. Additionally, nonprofits have leveraged 3D printing to distribute prosthetics to resource-limited communities--overcoming barriers previously posed by high costs and logistical challenges. However, the implementation of 3D-printed prosthetics varies significantly across countries due to differing national certification standards that ensure device safety and effectiveness. While these regulatory pathways are essential, they can also impact access and innovation, as certification processes can be lengthy and costly. For example, in the United States, the FDA requires rigorous testing and approvals for prosthetic devices, particularly those intended for children. In the European Union, the Medical Device Regulation (MDR) establishes strict certification protocols, including design transparency and quality control. Consequently, while projects like \"e-NABLE\" successfully distribute 3D-printed prosthetic hands to underserved regions, further adaptation is often necessary \begin{table}
\begin{tabular}{c c c} \hline \hline
**Material Type** & **Characteristics** & **Applications in Prosthetics** \\ \hline \hline \multirow{2}{*}{Polybactic Acid (PLA) [48]} & Biodegradable, easy to print, low strength & \begin{tabular}{c} Suitable for basic prosthetic models and non-load-bearing components \\ \end{tabular} \\ \hline \hline \multirow{2}{*}{Acrylonitrile Butadiene Styrene (ABS)} & \begin{tabular}{c} Durable, higher strength than PLA, resistant to impact \\ \end{tabular} & \begin{tabular}{c} Used for structural components and housing for electronics \\ \end{tabular} \\ \hline \hline \multirow{2}{*}{Nylon [48]} & High flexibility, excellent & Ideal for joints, gears, and load-bearing parts in functional prosthetics \\ \cline{2-3}  & strength-to-weight ratio, resistant to wear & \begin{tabular}{c} Used in flexible joints and sockets that \\ require cushioning \\ \end{tabular} \\ \hline \hline \multirow{2}{*}{Pyberther Ether Ketone (PEEK) [50]} & \begin{tabular}{c} High mechanical strength, chemical, and thermal resistance \\ \end{tabular} & \begin{tabular}{c} Suitable for high-performance prosthetic \\ parts in demanding applications \\ \end{tabular} \\ \hline \hline \multirow{2}{*}{Resin (SLA/DLP Printing)} & Smooth finish, suitable for detailed parts, variable flexibility & \
\begin{tabular}{c} Best for cosmetic covers and intricate \\ parts; limited strength for structural use \\ \end{tabular} \\ \hline \hline \multirow{2}{*}{Carbon Fiber Reinforced Polymers [2]} & Lightweight with high stiffness &
\begin{tabular}{c} Used in prosthetic frames and \\ load-bearing components for \\ high durability \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Comparison of materials for 3D-printed prostheses. This table highlights various materials used in 3D-printing prosthetic devices, along with their specific advantages and applications in prosthetics. to comply with local standards and achieve formal medical certification, ensuring user safety [4; 5]. The global volunteer network \"e-NABLE\" exemplifies this approach, using 3D printing to produce personalized prosthetic hands for children and adults and demonstrating the power of open collaboration. Volunteers design and deliver custom prosthetics to individuals who might otherwise lack access. Despite these efforts, regulatory challenges remain in securing certification for such devices across countries, where regulations vary widely and may limit their clinical use.