Rapid prototyping gains new roles in humanitarian causes.
By Jean Thilmany, Associate Editor
Advocates of rapid prototyping believe the small industry has the potential to be the next big thing. They see a future where custom-built objects replace mass-produced items.
But Behrokh Khoshnevis says the true potential for rapid prototyping, also known as additive manufacturing, will be realized in large-scale buildings, constructed quickly. Constructing housing via rapid prototyping methods, he said, will save time and money and bring affordable and environmentally friendly housing to people in need.
Khoshnevis, a professor of industrial and systems engineering at the University of Southern California in Los Angeles, is now at work on ways to construct relatively large buildings and other structures via the additive manufacturing process.
“I personally think the true potential of additive manufacturing is in larger scale building constructions because there’s no competition for it and the size of the industry is so large,” Khoshnevis said. “The building industry is a trillion dollars per year in the United States.
“And its low cost would make the housing affordable,” he said.
Low-cost housing isn’t the only area in which rapid prototyping could be used toward humanitarian ends. Rapid Prototyping for Baghdad, a humanitarian effort founded by companies in the rapid prototyping and manufacturing industry, uses additive manufacturing to make customized prosthetic limbs and orthotics for severely injured people in Iraq.
And in Vancouver, Canada, two-year-old 3d3 Solutions, has designed a 3-D, white-light, portable laser scanner that measures people being fitted for medical devices such as prosthetic legs, said Thomas Tong, the company’s president.
In each instance, the technology that makes additive manufacturing or rapid prototyping attractive to small-scale manufacturers—especially the ability to produce bespoke objects quickly—enables it to serve as a humanitarian tool.
>>> automated construction
In Khoshnevis’s vision, using an additive-manufacturing technique for constructing new buildings could provide emergency housing for victims of disasters. The technique could also be used for affordable housing for those in the United States or in third-world countries, or for creating new housing styles that bring curved, organic designs rather than straight surfaces to the homes.
Khoshnevis, the director of the Center for Rapid Automated Fabrication Technologies at USC as well as director of its manufacturing engineering program, began work on this project about 15 years ago. Khoshnevis and his CRAFT colleagues are working to develop the engineering tools and know-how to fabricate via the rapid prototyping process large structures such as boats, industrial objects, and public art.
But the grand challenge for CRAFT, he added, is to build a custom-designed house in a day while drastically reducing the costs, injuries, waste, and environmental impact associated with traditional construction techniques.
“I’ve been concentrating on building larger scale industrial stuff through the program, but only in the last few years I started thinking about using to this for building construction,” he said. “I’ve tried different materials. I tried ceramics, and then plaster, and then I said, well why not try concrete? And then it was obvious the process has potential with buildings.”
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, as made by an additive manufacturing
process, and its construction site.
To carry out additive-manufacturing building construction, Khoshnevis invented contour crafting. This hybrid fabrication combines extrusion for forming object surfaces and the additive manufacturing process to build up the structure’s core in a layered fashion.
The machine that does this crafting is actually a large gantry robot that weighs less than 500 pounds. The robot is armed with a extrusion nozzle for the layering process, Khoshnevis said, as well as a trowel that automatically smoothes over the outer surface of each layer.
The nozzle can be deflected to create surfaces such as domes and vaults. 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.
Innovations such as this have been rare in the U.S. construction industry, Khoshnevis said, because it is fragmented and dominated by small-to-midsize companies.
“This situation has stifled advances and innovation in new materials and production practices,” Khoshnevis said. “There’s little incentive for development of new materials or construction techniques.”
Costs for a building constructed via the additive manufacturing process would be about one-quarter less than for similar size buildings constructed in a traditional manner, Khoshnevis said.
In industrialized countries, automating the manufacturing of products like shoes or cars can cut costs about 25 percent as compared to manual construction methods, he said.
“Efficient automation of construction should result in similar cost reduction,” Khoshnevis added.
His team expects these savings to be realized because additive manufacturing reduces time to market, which drastically cuts construction costs, nearly eliminates material waste, and reduces labor expenses, Khoshnevis said.
“Also, the process is environmentally friendly,” Khoshnevis said, “as it uses less than 30 percent of the energy consumed in current construction.”
CRAFT’s goal is to make full-scale demonstration of an entire building within the next three years.
“So far, what we’ve been doing has been onsite in the lab,” Khoshnevis said. “But with the next generation of machines we should be able to take them outside to build structures.
“Our hope is to have the first actual building within the next three years,” he added. “They’ll be relatively smaller structures—about 1,000 square feet.”
The project has been financed so far by National Science Foundation and Office of Naval Research grants as well as by the Annenberg Foundation and through the help of some manufacturers such as Caterpillar.
>>> offering aid
The rapid prototyping process is being matched with humanitarian efforts in another project, this one situated in war-torn Iraq.
Last October, after reopening its office in Iraq, Doctors Without Borders took over the ongoing Rapid Prototyping for Baghdad, or RP4Baghdad, project. That project was started in 2005 by a number of industrial groups including Materialise, a software company in Leuven, Belgium.
The intent of the non-political project is to help civilian victims in a place where rapid prototyping technologies can make the difference between life and death, said Fried Vancraen, Materialise chief executive officer. His company supports the project with free medical models, software, and training.
Other companies involved with the project include 3-D Systems, Stratasys, Z Corp., Medical Modeling, and Wohlers Associates.
Engineers at the Center for Rapid Automated Fabrication Technologies
at the University of Southern California are working on the tools to
construct structures such as walls and buildings (including embellishments)
by using rapid prototyping methods.
The project provides 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. The focus is on the most serious cases, usually involving head injury or a lost leg, Vancraen said.
Iraqi doctors first make a 3-D computer tomography scan of the patient. They then send the data over the Internet to a company involved with the project along with a request for materials or advice.
That company turns the scan into a digital model and uses the model to create the prosthetic by additive manufacturing. The materials and models are shipped to Iraq and the surgery takes place.
Most patients are transferred from Iraq to Amman, Jordan, for these operations, Vancraen said.
Sometimes the project has meant the different between life and death, Vancraen added. For instance, a 30-year-old male student at an Iraqi technology institution was caught in a bomb explosion while on his way to his school in February 2006. During an examination in the hospital, doctors learned that the explosion had taken parts of the student’s skull and sent shrapnel into his brain. The patient also lost his left eye, three fingers, and his hearing in the explosion.
The student needed an artificial bone in his skull, an artificial eye, and a hearing aid, according to Ahmed Adnan, the surgeon who eventually operated on the patient at the Al-Ameer Hamza Hospital in Jordan.
Materialise designed the artificial bone—or implant—based on scan information provided by Adnan while Uni-Dent of Leuven, Belgium, manufactured the implant, Vancraen said.
Nearly four years after the blast, the patient is doing well and now works as a police officer in Iraq.
>>> beyond plaster
Other companies are also working to drive down costs and to bring reverse engineering and rapid prototyping methods to a larger audience. One company does this by making low-cost, white-light scanners that can be used in the field to take accurate human measurements.
When it comes to scanning a person, as opposed to a part, in order to create a customized product or to properly fit a patient with a prosthetic, dental implant, or another type of medical device, patience can be key, said Thomas Tong, 3d3 Solutions president.
“People aren’t going to stand still for a coordinate measuring machine that takes 30 minutes to do a couple of measurements,” Tong said. “But they’re afraid of lasers and a lot of the scanners that scan humans are laser based.
“Most scanners are built for the lab environment,” Tong said, “but most human measurements can’t really be taken in a lab environment.”
His company’s system—meant for quick, non-lab based human measurement—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, Tong said.
Orthotics and prosthetics manufacturers are turning to nonlaser 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.
The white-light laser scanner can also be used in the field and can be operated by technicians without much training, he said. The scanners cost from $1,500 to around $10,000, depending on configuration.
The system has already found a home with makers of braces and supports for limbs and spines.
“Orthotics manufacturers like it because they can measure feet without having to bother with specialized equipment or with casts,” Tong said.
“Traditionally, the way to measure a limb is to create a plaster cast of it or to take some measurements by hand,” he continued. “But the problem with the plaster cast is that creating the plaster is a kind of an art, and then the cast can be damaged in shipping. And the problem with measuring by hand is that people are malleable, so it’s hard to tell the exact distance from point x to point y on a human body.”
Tong also sees a future for systems like his in the medical device industry. Take, for example, a sleep-apnea mask that patients use with a continuous positive airway pressure machine while they sleep. The mask needs to fit securely as patients toss, turn, and roll over in bed.
“No one wants something like that to just be plastered on their face,” Tong said. “To create a custom mask, a technician could take a basic CAD model and modify it to match your data and then they could rapidly prototype a device just for you.”
Custom medical devices and low-cost housing—affordable for everyone and quick to manufacture accurately—will help grow rapid prototyping into a robust industry, said USC’s Khoshnevis. And one with a potentially humanitarian bent.