n low- and middle-income countries (LMICs), access to well-fitting prosthetic sockets remains limited due to high costs, restricted availability, and a shortage of trained clinical personnel. Existing prosthetic socket solutions often rely on specialised fabrication processes or result in discomfort and limited long-term acceptance, making them impractical for low-resource settings. This thesis explores a novel 3D-printed mechanical principle for shaping transradial prosthetic sockets directly on the residual limb of adults during the initial fitting process, without the need for trained clinical personnel, to reduce fabrication time and improve accessibility in low-resource settings. An iterative design process was followed in which multiple concepts were developed for a flexible inner layer capable of conforming to residual limb surface irregularities, alongside a rigid outer layer for circumferential adjustment. Selected concepts were refined and integrated into a final socket design. A functional prototype was fabricated using FDM 3D printing and evaluated through experimental testing, focusing on shape conformance, shape retention, and peak pressure behaviour. The resulting MetaWave socket consists of a waving-cell metamaterial inner layer combined with a pin-push circumferential adjustment mechanism. Experimental evaluation demonstrated that the prototype can accommodate the required circumferential range and conform to representative surface irregularities of the residual limb, while maintaining elastic behaviour under radial loading. Peak contact pressures generally remained below predefined thresholds, indicating effective pressure distribution. These results confirm the feasibility of the proposed shaping principle at a proof-of-concept level and highlight the potential of mechanically driven metamaterial structures as an accessible and adaptable approach to prosthetic socket design in low-resource settings

Background: Commercially available upper limb prostheses for playing guitar require professional assistance for proper fitting and usage. For people who lack this opportunity, alternatives are offered as research models or open-source models. However, adjustable models still require fitting assistance while parameter adjustment is extremely limited. This limits the user’s ability to play more complex music.

Goal: This project proposes the design of a low-cost passive adjustable 3D printed upper limb prosthesis for people with no access to professional prosthetic assistance.

Methods: Both design and evaluation methods were applied. Regarding design, early concepts were designed and selected using a Morphological table and Harris profile, applying rapid prototyping for initial comparison. Regarding evaluation, a parameter measurement and a device functionality test with users with and without upper limb differences were performed.

Results: The final model was successfully printed using Fused Deposition Modeling. The model was evaluated via parameters measurements and a user device functionality test. Results showed that the device allowed the user to put the elbow as a reference point to aid mental mapping of the prosthesis. Speed and accuracy measured during the test suggest a positive outcome for end users.

Conclusion: This design presents an accessible and reliable solution for users with upper limb differences who want to improve their guitar playing skills without the need of professional assistance.