3-D printing is the hottest new technology on the block. But for medical devices applications, the lack of suitable 3-D printable materials is inhibiting the widespread adoption of this technology. A key obstacle impeding the introduction of new 3-D printable materials has been low demand, rendering commercialization both difficult and expensive. That's the bad news. The good news is that efforts to develop new 3-D printable materials for medical device applications are assiduously under way.

What new 3-D printing materials are available for medical device applications? How can manufacturers overcome the limitations of existing materials? 3-D printing expert Tim Lew will offer his insights into these and other topics at MD&M Minneapolis on Wednesday, October 4 in a presentation titled "Uncovering New Materials for 3-D Printed Medical Devices."

The still relatively small market for 3-D printing technologies in the medical device space is a supply and demand problem, Lew states. As people develop new applications, they will create new materials for these applications. "In the fused deposition modeling (FDM) area, for example, suppliers of small-filament materials such as ProtoPlant and Zen Toolworks can bring new materials to market quickly and in small batches. Also, manufacturers ability to 'create' their own 3-D printing data with easy-to-use, low-cost scanners will help increase the demand for new materials."

As 3-D printing becomes more mainstream, 3-D printers will become easier to use, easier to purchase, and cheaper, according to Lew. While it is possible to buy a consumer 3-D printer at Staples and Home Depot or 3-D print objects at a UPS store, material choices are limited to ABS and PLA. As the demand for access to 3-D technology increases and the barrier begin to fall, the demand for different materials will follow. In addition, the expiration of many 3-D printing patents will stimulate more innovation and increase manufacturers' freedom to invent, create, and experiment with new materials.

Right now, only a handful of 3-D printing materials are accepted and cleared for use in medical device applications, Lew comments. For external use in such applications as braces, guides, or casts, nylon 11 and PLA are safe for limited skin exposure. For implantable applications, commonly used materials include titanium, stainless steel, cobalt-chromium, and PEKK. Materials on the horizon, Lew adds, include nitinol, magnesium, ceramics, and superalloys, all of which are being tested in academic and research settings.

Nevertheless, while a few medical device-compatible materials are currently used in 3-D printing applications, these scant materials are subject to a range of limitations. "These materials," according to Lew, "exhibit long postprocessing times, limited z-plane resolution, and inconsistent machining quality. Existing materials also face a host of heat sterilization challenges and strength issues. In addition, sources offering consistent base materials are still unreliable."
The materials challenges only become more daunting when manufacturers seek to add embedded electronics to 3-D printed medical devices. True, manufacturers will soon be able to 3-D print such devices as custom foot orthotics containing space for pressure or temperature sensors, but broader moves toward commercialization are still far off, despite many research efforts.

"3-D printing still isn't on the scale where it can print real electronics--in other words, semiconductors, Lew says. "A lot of work is going into incorporating conductive filaments for printing circuit traces into devices, but that's the easy, low-hanging fruit. Right now, we can't 3-D print much beyond extremely clumsy analog electronics." Thus, while it is possible to use 3-D printing to fabricate resistors, capacitors, and inductors, creating LEDs, processors, and other chip-based electronics is still a long way off. Until that day comes, any 3-D printed object incorporating embedded electronics will have to undergo considerable assembly time.

Despite the many challenges facing the widespread commercial adoption of 3-D printing techniques in the medical device sector, leveraging the technology to satisfy the demands of increasingly complex medical devices is progressing, Lew notes. Its further development will enable engineers to think outside the box and expand the range of the technology's possibilities.

Bob Michaels is senior technical editor at UBM Canon.

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