August 2012

Additive manufacturing inches toward prime time

Digital design of an internal lattice structure for orthotic additive manufacturing. (Photo courtesy of Chris Lewis Jones/Delcam.)

By Jordana Bieze Foster

The fledgling field of additive manufacturing is still somewhat fragmented, as evidenced by the fact that the same technology can be described as rapid prototyping or 3D printing. But additive manufacturing’s profile is definitely on the rise, and its advocates are optimistic that lower extremity clinical applications are right around the corner.

The technology, in which objects are built from individual layers of material stacked on top of each other based on a digital design, made headlines in early July with the unveiling of a prototype running shoe fabricated using only additive manufacturing. Luc Fusaro, a student at the Royal College of Art in London, designs each prototype based on scans of an athlete’s foot as he or she performs different athletic tasks. All nones­sential material is subtracted from the design, resulting in a latticed nylon shoe that weighs just 96 g, conforms precisely to the contours of the foot, and purportedly can improve sprinting performance by as much as 3.5%.

Two European organizations, e-Custom and SAVING (Sustainable product development via design optimization and AdditiVe manufacturing) are also devoting resources to advancing the technology. But the biggest vote of confidence for additive manufacturing may have come from technology giant Hewlett Packard, which entered the additive manufacturing market last summer with its DesignJet 3D printer.

“If companies like HP are getting involved, it’s not always going to be the small market it is today,” said Graham Bennett, managing director of CRDM, a provider of additive manufacturing technology based in Hemel Hempstead, UK, that is a Design­Jet reseller. Bennett was a presenter at the Orthotics Technology Forum in Manchester.

Additive manufacturing is ideal for implementing internal lattice structures, with which a hollow object can be made self supporting using less material than a solid structure, according to Chris Lewis Jones, manager of collaborative research projects for Delcam, who also presented at the conference. Other advantages include external lattice structures and the ability to grade materials for density or hardness.

“The whole thing gets built in one hit, so you don’t have to turn things over or upside down. That means you can increase the complexity without needing additional setup,” Bennett said.

In addition to running shoes, lower extrem­ity applications include corrective footwear, mod­­els for temporary prostheses, joint implants, and splints. Orthotic device fabrication can control material strength in specific directions, which could be used to limit motion and promote healing.

“What’s missing now is education on how to design for additive manufacturing,” Jones said. “But to be sure, it is going to be a part of our manufacturing future.”

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