Abstract

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. 1

Implications for Rehabilitation

• Designing open-source assistive devices for replicability allows clinicians, technicians, and local makers to fabricate, repair, and adapt them to users’ needs, using locally available materials, off-the-shelf components, and equipment.
• Open-source, 3D-printable forearm crutches can provide affordable mobility aids, locally produced in low-resource distributed manufacturing contexts, improving the accessibility and affordability of assistive devices.
• Easily replicable open-source assistive products can support long-term use and continuity of care by facilitating repair, replacement, and adaptation over time.
• Considering replicability as a design constraint from early design phases, together with product-specific quantitative assessment, can improve the real-world adoption and safe use of open-source assistive products in low-resource, distributed rehabilitation settings.
  
  

Resources and links

• 📝 Full text (preprint version) 2
• 📑 Full text (publisher version) 3
• 🛠️ OSF Repository (3D models and dataset) 4
• 🛠️ OSF Repository (3D models of the testing rig) 5