Originally Published MPMN November 2002

INDUSTRY NEWS

Rapid Prototyping Provides Clearer Picture

Elaine Paoloni

When 2-D images weren't an adequate solution to help separate conjoined twins in a Los Angeles hospital recently, medical professionals turned to the QuadraTempo rapid prototyping system by Objet Geometries (Rehovot, Israel; www. objet.co.il). Joined at the head, the Guatemalan twins had blood vessels that were intertwined, making it almost impossible to use 2-D x-rays as a guide. Facing a challenging and delicate operation, doctors believed a 3-D rapid prototyping system would work best to allow plastic surgeons to practice rerouting the blood supply and grafting skin to cover the separated brains.

Biomedical Modeling Inc. (Boston; www.biomodel.com), a rapid prototyping system fabricator for medical applications, combined three CT scans of the twins at different angles to create a single 3-D model. The company used MIMICs software from Materialise (Ann Arbor, MI; www.materialise. com) to merge the scans and process the data. The services of InterPRO (Deep River, CT; www.interpro-rtc.com/) were then sought to produce the actual prototypes.

A rapid prototyping service bureau, InterPRO built the models with QuadraTempo. The system uses Objet Geometries' PolyJet process, which creates parts by jetting the company's proprietary photopolymer materials in 20-µm layers, curing each layer with ultraviolet light immediately after it is deposited. A second, gel-like photopolymer material is used for support, and is later easily removable by water jets.

"The QuadraTempo's ability to build the delicate features without support structures allowed us to clean the models much more easily after printing them," says InterPRO coowner Kevin Dyer. "The fine details in the Tempo models proved especially critical to achieving success, since the surgeons needed to look inside the model and plan the rerouting of the blood vessels."

The PolyJet process's high resolution, 0.0008-in. layers, and features as small as 0.002 in. produce fine detail and smooth surface characteristics without labor-intensive sanding and finishing operations. The elimination of complicated postprocessing and the benefit of fast build times enable clients to deliver high-resolution prototypes faster and at a lower cost than competing technologies, according to the company.

"The design and product engineers who use such prototypes can analyze and evaluate different situations, permit better planning, enable trial- and-error of real-life actions, and immediately improve the diagnostic process," says Hanan Yosefi, CEO of Objet Geometries. "Only then will they make all necessary adjustments, before they move into the mass-production process. Imagine how much more cost-effective it is to find a defect or error at the prototype stage, rather than finding it at the mass-production stage."

The company's PolyJet process is now available on-line at www.atirapid.com. Powered by the rapid prototyping service bureau Accelerated Technologies Inc. (Erlanger, KY), the site provides instant quoting for 3-D printed rapid prototypes. Customers can submit files for printing or jetting and receive price quotes and production-time information over the Internet.

Copyright ©2002 Medical Product Manufacturing News