Experimental development of 3D printed hands prosthetics

Details

Supervisors

Herman, Benoît ; Wendo, Kevin

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil électromécanicien, à finalité spécialisée: mécatronique

Abstract

enLimb loss affects millions of people worldwide, not only physically but also psychologically and socially. While prosthetics can alleviate some of the trouble caused, they are often considered too expensive for people in countries where low quality of life or even conflict can causes limb loss, with prices ranging from 1000 to 150 000 euros. For this reason, researching the possibility of 3D printing prostheses might be a valuable option due to their cheap nature. Sadly, there is a lack of validation studies for such models. This thesis builds on the previous work of P. Andre, which was focused on the design and development of a test bench for fatigue performance assessment. A first goal of this thesis is to continue the development of the test bench, notably make the necessary modifications to allow testing in a hot and humid environment. The second objective of this study is to assess the performances of existing designs of 3D printed hand prostheses on this test bench and propose modifications to enhance their fatigue performances. To this end, the enclosure was waterproofed and the electronics protected to withstand the chamber conditions, and a ventilation system was added to maintain safe operating temperatures for the recording hardware. On the software side, force measurement accuracy was improved, automatic video recording of events of interest was implemented, and data analysis tools were enhanced with color range calibration and automated video processing capabilities. Fatigue tests were conducted on two e-NABLE designs: the Phoenix Hand v3 and the Kinetic Hand. Under standard conditions, the base Phoenix Hand v3 averaged 4,271 cycles before failure, while a design modification developed in this work increased this figure to approximately 110,000 cycles,a 25-fold improvement. The Kinetic Hand demonstrated substantially greater durability, with all samples surviving beyond 120,000 cycles without fracture. Under environmental chamber conditions, the Phoenix Hand v3 suffered from a cable seizing failure mode caused by increased friction between the nylon tendons and PLA cable guides under heat and humidity. The Kinetic Hand, by contrast, reached 1,000,000 cycles in all samples without failure, suggesting strong suitability for deployment in warm and humid climates.