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U.S. Army Soldier & Biological Chemical Command
U.S. Army Soldier Systems Center-Natick
Public Affairs Office
Kansas Street
Natick, MA 01760-5012

Contact: Chief, Public Affairs Office
(508) 233-5340
amssb-opa@natick.army.mil

Date: May 16, 2001
No: 01-33

New machine gives Natick Labs unprecedented capabilities

Natick, Mass. --- A new rapid prototyping and manufacturing system in operation at the U.S. Army Soldier Systems Center (Natick) since January has brought unprecedented capabilities to the Rapid Prototyping Facility.

Since 1993, the Rapid Prototyping Facility has created solid 3-D Computer-Aided Design (CAD) models, conducted engineering studies using Finite Element Analysis (FEA) and produced 3-D prototypes directly from CAD data for a range of military and civilian projects.

"The machine is a useful tool for evaluating component or system design issues before actual fabrication," said Gary Proulx, mechanical engineer who manages the Rapid Prototyping Facility. "We can look at the 'what ifs' and build a real prototype for the soldier to use."

CAD and FEA software are used to design and analyze system components, such as a mount for Night Vision Goggles, in virtual space. The data is then transferred to a machine to create prototypes.

Helisys Laminated Object Manufacturing system was the first rapid prototyping machine used in the facility. It builds 3-D prototypes by using the CAD design data and stacking laminating layers of a special paper while a laser cuts the part boundary.

"The older system's prototypes had a wooden quality. If you wanted a plastic part, you then had to cast a mold," Proulx said.

Designers and engineers get a part they can visually inspect, study for its compatibility and analyze requirements. Laminating machine parts can also be used as master copies for manufacturing the items.

Similarly, the new Sinterstation 2500 Plus also starts by processing the 3-D CAD data, but paper is no longer used.

A precision roller mechanism automatically spreads a thin layer of powdered nylon across the build platform. Using CAD information, a laser selectively draws a cross section of the object on the layer of powder. As the laser draws the cross section similar to a contour map, it selectively "sinters" (heats and fuses) the powder creating a solid mass that represents one cross section of the part.

The steps are repeated as the system spreads and sinters layer after layer until the object is complete. After the part is complete, it's removed from the build chamber. Loose powder is dusted off.

With both systems, parts can be used for their intended applications as is or sanded, coated, or painted. Also, 3-D parts using CAD information are shaped within plus or minus five-thousandths of an inch.

"With the new system, we get a mold that's functional and is effective for thin-walled parts," Proulx said, displaying a palm-sized protoype tubing for a microclimate cooling system.

Besides plastic, the machine can produce rubber, metal or ceramic parts. Part stacking and nesting capabilities enable Proulx to build multiple unrelated parts, and without monitoring the operation. Functional prototypes, tooling, patterns and final parts are possible with the Sinterstation.

The Sinterstation's dimensions of 12 inches by 15 inches by 17 inches are smaller than the 32 inches by 22 inches by 20 inches of the Helisys, but it's not an issue for larger items. "We can build virtually any size part by breaking down the construction into smaller pieces and attaching the pieces," he said.

Instead of taking a week, the new system builds models in a day. Cost-savings are also significant. To build a unique part using injection-molding could cost $15,000-$20,000. The new machine builds parts for less than $50, Proulx said.

"For the mounting systems for Night Vision Goggles, we went over several design iterations. Once we had the design, we had the pieces machined," he said. "You really want to fine-tune your design before you turn it over to a process more laborious to get completed."

Some of the items he has produced with the machines are pieces for helmets, a model for wind tunnel testing, and mock-up equipment for Land Warrior and Future Warrior. The largest item produced was a car-door frame under an agreement with Drexel University in Philadelphia.

"We've done some work on the outside, but with the new system, we're looking to do more," Proulx said. "We've seen a growth in business since the machine has arrived. The range of uses is really wide open."

Natick is part of the U.S. Army Soldier and Biological Chemical Command (SBCCOM). For more information about SBCCOM or the Soldier Systems Center (Natick), please visit our website at http://www.sbccom.army.mil.

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