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U-M Creating New Way to 3D Print O&P Devices

Albert Shih, PhD, a professor of mechanical and biomedical engineering and the lead on the project, displays a 3D-printed AFO. Photograph by Kelly O’Sullivan, courtesy of U-M Engineering.

Engineers at the University of Michigan (U-M) College of Engineering have developed a system to fabricate lighter, better-fitting O&P devices in less time than current fabrication methods, and practitioners at the U-M Orthotics and Prosthetics Center (UMOPC) are implementing the system. The digital design and manufacturing process improves the device’s consistency, precision, fit, and function, and makes the process more efficient for practitioners and patients. The U-M team is currently focusing on AFOs, but the system has also been used to produce prosthetic devices. Eventually, the software and specifications will be available at no cost so that other healthcare providers can create similar systems. Then, any clinic with a 3D printer could repeatedly produce exactly the same device, and the models could provide a record of the changes to the patient’s condition over time.

The new technique begins by creating a 3D optical scan of the patient. The practitioner uploads the scan to a cloud-based design center and uses the specially developed software to design the assistive device. Next, the software creates a set of electronic instructions and transmits them back to the practitioner’s facility, where an on-site 3D printer produces the actual device in a few hours.

“The new process is a major departure from the current labor-intensive process that requires a large shop and a highly trained staff,” says Jeff Wensman, BSME, CPO, director of clinical and technical services at UMOPC. The only on-site equipment required by the new process is an optical scanner, a computer, and a 3D printer, which could benefit small clinics in remote areas.

The 3D-printed devices weigh less than current devices, without sacrificing strength, due to a technique called “sparse structure.” This makes the device partially hollow using a wavy internal structure to infill the interior of the orthoses and increases machine efficiency, which allows the team to print parts quickly.
“Traditional hand-made orthotics are solid plastic, and they need to be a certain thickness because they have to be wrapped around a physical model during the manufacturing process,” Wensman said. “3D printing eliminates that limitation. We can design devices that are solid in some places and hollow in others and vary the thickness much more precisely. It gives us a whole new set of tools to work with.”

The project is funded by the National Science Foundation and America Makes, a partnership between industry, academia, government, and others to develop advanced manufacturing and 3D printing capabilities in the United States.

Editor’s note: This story was adapted from materials provided by U-M Engineering.