Materials for rapid prototyping (RP) and direct digital manufacturing (DDM) are more prevalent than ever in medical-device applications, including those requiring ISO-compliant materials. For instance, ABS, PC-ISO, and PC-ABS blends are materials of choice because they are biocompatible, ISO 10993-certified, and can be sterilized using either gamma radiation or ethylene oxide (EtO). Blends combine the strength of polycarbonate with the flexibility of ABS and a V-Zero flammability rating of PPS (polyphenylsulfone).

Dual ABS options

ABSi and ABS-30 are two versions of ABS (acrylonitrile-butadiene styrene) commonly used in rapid prototyping applications. ABSi (Methyl methacrylate-acrylonitrile-butadiene-styrene copolymer) is an engineering grade of ABS used to make parts directly from digital files. Parts using ABSi can be used from conceptual prototyping through design verification through DDM (direct digital manufacturing). Since ABSi is semitranslucent, it is appropriate for monitoring material flow and light transmission in medical-device applications.

The second ABS option, ABS M30, is up to 70% stronger than traditional ABS, with greater tensile, impact, and flexural strength. The material's strength provides more prototyping and DDM options for designers and engineers. For example, the material works well in conceptual prototypes and design verification, to evaluations of form, fit, and function. ABS M30 provides greater dimensional stability than standard ABS because of stronger layer bonding. The result is more realistic functional tests and higher quality parts for end use.

A recent “heart-sustaining” effort involved PC-ISO Class VI materials and Ablation Frontiers, Carlsbad, Calif. (ablationfrontiers.com), a maker of medical devices that restore normal heart function to individuals with cardiac arrhythmias. Ablation Frontiers recently needed to produce 2,500 ablation tools within four months for a trade show. Ablation Frontiers selected RedEye, Eden Prairie, Minn. (redeyeondemand.com) as its prototype and parts-building service. RedEye selected the PC-ISO material, which passed biocompatibility testing standards to comply with ISO 10993-1 and USP Class VI rating systems, and it met Ablation Frontiers' four-month deadline while staying within the budget.

Materials for rapid-prototyping and direct-digital manufacturing will continue advancing. And with these developments will come greater opportunities for designers and engineers of medical devices to develop innovative products while reducing time to market.

Editor's note: For more on rapid technologies, please see this month's R&D Notebook.