Rapid Prototyping:
The Human Touch


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Rapid Prototyping: The Human Touch - Computational Methods & Modeling

Behrokh Khoshnevis and his colleagues at the University of Southern California are developing engineering tools to fabricate buildings and houses via the rapid prototyping process. The photo depicts a mock-up of a partially constructed building made by an additive manufacturing process.

Natural disasters and military conflicts have different root causes but their devastating human impacts are the same. Whether it’s a community struck by a tsunami in Japan or a civilian caught in the cross fire of an insurgency in the Middle East, the common denominators are lost homes, lost health, and, too often, lost hope.

Rapid prototyping (a.k.a., additive manufacturing) is finding new uses in humanitarian applications, helping to restore communities and lives in countries coping with catastrophe. Some experts say that these humanitarian efforts may at last reveal the true industrial potential of this still-emerging technology.

Behrokh Khoshnevis, a professor of industrial and systems engineering at the University of Southern California, Los Angeles, CA, believes large-scale, rapidly constructed buildings represent the future of rapid prototyping, in part because it’s an untapped niche in the trillion-dollar U.S. building industry. But on the humanitarian side, he says constructing relatively large buildings via rapid prototyping methods will save time and money and bring affordable, environmentally friendly emergency housing to people displaced by natural disaster.

The same technology also provides hope for people severely injured by armed conflict.

Orthotics and prosthetics manufacturers are turning to non-laser methods of scanning the human body, because the methods let them measure body parts, like feet, without the need for special equipment or casts. The scans help create customized medical implants.

Rapid Prototyping for Baghdad (RP4Baghdad), a humanitarian effort founded by companies in the rapid prototyping and manufacturing industry, uses additive manufacturing to make customized prosthetic limbs and orthotics for wounded Iraqi citizens. 3d3 Solutions, based in Vancouver, BC, Canada, has designed a three-dimensional, white-light, portable laser scanner that measures people being fitted for medical devices such as prosthetic legs.

Automated Construction

Khoshnevis, who heads USC’s Center for Rapid Automated Fabrication Technologies (CRAFT), began exploring rapid prototyping for affordable and nontraditional housing designs about 15 years ago. CRAFT’s grand challenge is to build a custom-designed house in one day while drastically reducing the costs, injuries, waste, and environmental impact associated with traditional construction techniques, he says.

Khoshnevis’ solution was to invent contour crafting, a hybrid fabrication method combining extrusion for forming object surfaces and the additive manufacturing process to build up the structure’s core in a layered fashion.

Contour crafting is performed by a 500-lb gantry robot armed with an extrusion nozzle for the layering process and a trowel that automatically smoothes the outer surface of each layer. Objects can be made from more than one type of material. For example, the nozzle could extrude plaster as the outer surface material and concrete as the core structural material.

Khoshnevis said the technique could reduce building costs by about 25% by reducing time to market. That spells big reductions in construction costs, energy consumption, material waste, and labor expenses.

CRAFT’s goal is to translate its laboratory research on this concept into a full-scale, 1,000-square-foot demonstration building within the next three years.

Prosthetic Prototyping

The nonpolitical RP4Baghdad project was founded in 2005 by an international collaborative of industrial groups to create medical solutions for civilians severely injured in the Iraqi war and subsequent insurgency. It’s now managed by the humanitarian group Doctors Without Borders.

Fried Vancraen, chief executive of the Belgium-based software firm Materialise, said his company’s role is to provide Iraqi surgeons with the software and 3-D models needed to plan craniofacial and maxillofacial operations and to fit patients with prosthetic limbs without the need for manual measurements and fittings, which can be less than perfect.

After Iraqi doctors make a 3-D computed tomographic (CT) scan of the patient, they transmit it electronically to one of the partner companies along with a request for materials or advice. That company turns the scan into a digital model used to create the prosthetic, which goes back to the clinic in Iraq.

The scanner from 3d3 Solutions is another example. It’s meant for quick, nonlaboratory-based human measurement. It comprises a digital camera tied to a laptop and a projector. Light from the projector casts computer-generated black-and-white patterns against the object to be measured. Those patterns are input into a software application and the measurements are used to construct the customized 3-D model, says 3d3 President Thomas Tong.

The white-light laser scanner can also be used in the field and can be operated by technicians without much training, he says. The scanners cost from $1,500 to around $10,000, depending on configuration.

Tong says the ability to produce bespoke objects quickly–in other words, the same trait that makes it attractive to small-scale industrial manufacturers–enables rapid prototyping to create biomedical solutions in humanitarian situations beyond the reach of a traditional clinic.

[Adapted from “Part of the Solution,” by Jean Thilmany, Associate Editor, Mechanical Engineering, January 2010.]

Rapid prototyping is finding new uses in humanitarian applications, helping to restore communities and lives in countries coping with catastrophe.

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February 2012

by Jean Thilmany, Associate Editor