Effect of printing orientation on structural strength of 3D-printed polylactic acid prosthetic socket using fused deposition modeling.

Abstract

Background: Recent fused deposition modeling (FDM) technology could offer accessible socket fabrication and resolve conventional fabrication issues. However, the printing orientation in FDM affects the structural integrity and reliability.Objective:To examine the effect of printing orientation on the structural strength of 3D-printed sockets using FDM.Study Design:Experimental study of 3D-printed socket at different printing orientations in static and cyclic loadings.

Methods: This study scanned residual limbs of 2 transtibial amputees weighing 53 kg (P4) and 125 kg (P6) to create 3D-printed prosthetic sockets using FDM. Ten sockets of a P4 amputee were printed at various orientations from 0° to 90° for a structural static test. In addition, 6 sockets of the P6 amputee were printed at 90° for static and cyclic tests according to ISO 10328.

Results: Based on the results, sockets printed at 0° and 90° for the P4 amputee exceeded static ultimate force under condition I according to ISO 10328 standards with 4880 N and 4430 N, respectively. Sockets at 30°, 45°, and 60° failed before the minimum force requirement was reached. Further validation of the 90° printed socket passed the static test in conditions I and II, and the cyclic test in condition II, enduring 3 million cycles without failure.

Conclusion: The 0° and 90° printing orientations are recommended for their superior mechanical properties, whereas other orientations may pose safety risks because of insufficient structural strength. These findings could contribute to developing more reliable and durable prosthetic sockets that meet ISO 10328 standards to enhance the quality of life for amputees.