Streamline digital workflow for 3D printed ankle-foot orthotics, AFOs

The University of Michigan CYBER Team combines cloud-based designs and Stratasys FDM technology to address the challenges in the orthotics design methodology for 3D printing durability, material strength, system integration, and throughput, and ultimately streamline patient care so orthotic outpatient visits can be lowered from three to one.

Students develop affordable 3D-printed ankle-foot orthosis, AFOs for children. Gonzaga University

by Sarah Saunders, 3Dprint.com July 13, 2018

The CYBER Team, which stands for Cyber-Physical Design and Additive Manufacturing of Custom Orthoses, is on a mission to leverage 3D printing and Industry 4.0 to make better Ankle Foot Orthotics (AFOs) and more specifically, to address the orthotics needs of veterans. Funded by America Makes, the national accelerator for 3D printing and additive manufacturing based in Youngstown, Ohio, the CYBER team was formed in 2016 by Stratasys, the University of Michigan, and Altair Engineering.

At the moment, existing methods for designing and manufacturing custom orthoses are time-consuming for both patients and providers, as well as inaccurate. By replacing traditional methods with 3D printing, we have the potential to increase mass customization and overall adoption of the technology in the O&P field, in addition to improving the function of orthoses.

America Makes just published a success story on the latest result of the CYBER Team’s hard work.

The project, which aligns with ASTM International Material Extrusion process category, has a total budget of $2 million, split between public and private funding, and additional partners include Becker Orthopedic, Standard Cyborg. and the VA Ann Arbor Healthcare Center; the Department of Energy, the National Science Foundation, and the Department of Defense are public participants.

According to America Makes, “The objective of this effort is to create a cyber-physical fused deposition modeling (FDM) production system enabling the mass production of individualized orthoses. The ultimate goal is to offer ‘one day visits,’ so that patients receive their custom orthosis on the same day that they are evaluated. To achieve the throughput and performance requirements, advancements in design for AM, specialized material offerings, system improvements, and a method to print multiple materials are needed to provide a high quality orthosis.”

By developing 3D printing-specific functionality, built on optimization software package Altair OptiStruct, the CYBER Team hoped to streamline the 3D design digital workflow. OptiStruct made this possible, as it can digitally validate performance and generate unique fill patterns. Stratasys’ job was to use its FDM technology – specifically its Fortus 400mc 3D printer – to make important improvements in material offerings and throughput.

Back in 2016, Jeff Wensman, the Clinical/Technical Director of the U of M’s Orthotics and Prosthetics Center, explained, “Different amounts or types of material can be printed to provide a specified stiffness and allow areas of flexibility, based on the patient presentation. This exciting technology opens up an entirely new tool box that the clinician can use to enhance patient outcomes.”

The AFO performance-based methodology is based on topology optimization, which balances increased deposition rates and efficient tool path movement with the distribution of material, using adaptive sparse fill patterns, according to the required loading conditions. Combining manufacturing technology and AM digital design development to produce customized AFOs made it possible to use 3D printing to balance the performance, throughput, and weight of AFOs.

The CYBER Team was ultimately successful in its efforts to create a digital 3D design workflow, thanks to developing 3D printing-specific functionalities. Team members were able to use Stratasys FDM technology make improvements in material and throughput offerings, while at the same time setting up an intuitive O&P industry-specific design centered on producing customized AFOs.

America Makes wrote, “The challenges of uneconomical throughput and high material cost, multiple material deposition, and the lack of a clinical interface were solved and demonstrated to achieve a ‘one day visit’ through the development of a ‘Design for Additive Manufacturing’ methodology which provided a balance of strength, weight, and throughput. The team successfully accomplished its technical objectives and proved that AM can have a large impact on the healthcare industry, particularly in the area of customized medical assist devices.”

The CYBER Team will focus on other targets for its continuing work in manufacturing advancements, including multi-material, next generation materials, and multi-head deposition.

Source 3Dprint.com

Assessment of a virtual functional prototyping process for the rapid manufacture of passive-dynamic ankle-foot orthoses, Schrank ES, Hitch L, Wallace K, Moore R, Stanhope SJ. J Biomech Eng. 2013 Oct 1;135(10):101011-7. doi: 10.1115/1.4024825.

Patient specific ankle-foot orthoses using rapid prototyping, Mavroidis C, Ranky RG, Sivak ML, Patritti BL, DiPisa J, Caddle A, Gilhooly K, Govoni L, Sivak S, Lancia M, Drillio R, Bonato P. J Neuroeng Rehabil. 2011 Jan 12;8:1. doi: 10.1186/1743-0003-8-1. Full text

Dimensional accuracy of ankle-foot orthoses constructed by rapid customization and manufacturing framework, Schrank ES, Stanhope SJ. J Rehabil Res Dev. 2011;48(1):31-42.

Manufacture of Passive Dynamic ankle-foot orthoses using selective laser sintering, Faustini MC, Neptune RR, Crawford RH, Stanhope SJ. IEEE Trans Biomed Eng. 2008 Feb;55(2 Pt 1):784-90. doi: 10.1109/TBME.2007.912638.

Also see
Transforming Ankle Foot Orthosis with 3D Printing Digital Engineering
Transforming Orthotics with 3D Printing and Industry 4.0 Stratasys