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Purdue researchers tweak CT scanners to help lumber industry find knots, cracks, decay in trees

February 9, 2009


CT scanners have been used for decades to peer inside humans. Now a Purdue University researcher is training the technology on hardwood trees to help lumber mills get the most value from logs.

Rado Gazo, a professor of wood products and industrial engineering, is leading development of a CT scanner that can detect grain patterns as well as defects like knots, cracks and decay by differences in wood densities.

Knowing what's inside could help mills decide how to position logs before sending them through saws, thus reducing waste.

Gazo began his research in 2005 and hopes to license the technology for commercial use. A working prototype could cost companies $1 million when it hits the market a year or more from now.

"What we are trying to do is to see if we can find and develop a scanner that can take the beating a sawmill can dish out," he said. "Those are big challenges."

The technology could revolutionize the hardwood industry, which directly or indirectly employs 130,145 Hoosiers, according to a 2007 study for the Indiana Department of Natural Resources.

Scanners have been objects of experimentation in the industry for years. The most common scanner currently in use, a geometric model, shows a sawyer how deep to cut or where to begin cutting, but can't see imperfections.

High-resolution X-ray scans could maximize the value of wood and help the industry face rising competition from Europe.

Gazo has secured roughly $2 million in grants and private and public funding to finance his research. The company developing the prototype, which Gazo wouldn't disclose, also is providing funding.

U.S. Sen. Richard Lugar, R-Indiana, who owns a 223-acre hardwood tree farm near Indianapolis, last year helped tap $875,000 from the federal government for the project.

"This has been something that the hardwood industry, not only in the United States but around the world, has been wanting to develop," said Lane Ralph, Lugar's deputy state director.

The Indiana State Department of Agriculture and the Indiana Hardwood Lumbermen's Association, a trade group of sawmills, brokers and other segments of the industry, also support Gazo's efforts.

Potential savings are not paltry. Gazo and his students learned in summer 2007 that a traditional hospital scanner led to their creating 20 percent to 40 percent more value from logs than approaches taken by a veteran sawyer.

Five species—hard maple, black cherry, yellow poplar, white oak and red oak—were run through the scanner at Pike Lumber Co. Inc., a sawmill in the northern Indiana town of Akron.

Pike Lumber President John Brown, who holds a Purdue forest management degree, thinks Gazo's idea might have traction.

"We were trying to prove the concept, and the concept has potential," he said. "Whether it can make that huge leap to practical, everyday production is what we're trying to answer."

The hospital test scanner, however, could inspect logs only up to 18 inches in diameter. Gazo's version would accommodate much larger timbers and produce clear images.

The technology particularly could benefit the veneer industry by helping producers maximize thin, high-quality slices of wood that are glued onto less valuable pieces. Getting the most from veneer logs is important because each log can cost thousands of dollars.

Gazo envisions hauling a scanner on a trailer to a log auction or sale to help determine quality before purchases are made. Typically, logs are bought and sold by guessing what is inside a log based on bark, history of the tree, or the site where it was grown.

A scanner that can examine standing trees or utility poles for signs of rot or decay also is being considered.

Assisting Gazo on the project is Sun Joseph Chang, a professor of forestry at Louisiana State University in Baton Rouge. Having spent 20 years researching CT scanner lumber applications, he is considered an expert and is developing software for the scanning application.

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