Design for replicability in open-source distributed assistive technology for low-resource settings: a case study of two-piece 3D-printed forearm crutches.

PURPOSE: Distributed manufacturing of open-source assistive technology shows potential to offer accessible, affordable, and customisable solutions for users in low-resource contexts. Their real-world adoption, however, depends not only on the availability of openly shared designs but also on their replicability when fabricated in different local contexts. This work investigates the replicability of open-source hardware in assistive technology through a practical design-driven approach, using the development and experimental evaluation of a two-piece open-source forearm crutch as a case study.

MATERIALS AND

METHODS

Replicability was considered from early-stage design and evaluated by introducing controlled variations from distributed manufacturing contexts, e.g. material feedstock, manufacturing equipment, and fabrication strategies. Four batches of crutches were fabricated and assembled using virgin and recycled filaments on small- and large-format 3D printers. After visual inspection, mechanical static load testing was performed following ISO 11334:2007, together with quantitative replicability assessment and economic analysis.

RESULTS

Comparable mean load-bearing and consistent failure behaviour were achieved across batches, supporting the replicability of the design in distributed manufacturing. The quantitative replicability assessment translated structural performance and batch variability into a measurable criterion for comparison. Limited cost variability was achieved, supporting repairability and product lifecycle extension, while enabling affordable, easy fabrication in local contexts.

CONCLUSIONS

Beyond this case study, the replicability of open-source hardware for assistive devices needs to be considered as an early-stage design constraint, e.g. developing products that allow for variability from local contexts and including product-specific quantitative approaches to assess replicability. This design shift can support accessibility and real-world fabrication of open-source assistive technology in low-resource settings.