June 2004        Volume 10, Number 6

California Mill Specializes in Redwood
Inovec StereoScan,YieldMaster system improve yield, production at head rig

By Diane Calabrese

ARCATA, California-- Tall and majestic, Sequoia sempervirens, the coast redwood, is a pleasure to see. Visitors to coastal areas of northern California have plenty of opportunities to walk among redwood trees. There are some 257,000 acres of redwood parks as well as 125,000 acres of public lands where the trees are conserved.

Outside the parks and reserves, many second-growth coast redwood trees dot private lands. They are harvested and milled into some of the most coveted wood products in the nation.

Lightweight and strong, coast redwood makes great material for fencing. Redwood fence is easy to lift into place time after time; ensuring alignment satisfies property owners. Nails push through it with no problem. And absent are excessive pitch and resin that can make other species of wood magnets for debris-- or worse, insects.

For 30 years, Britt Lumber Co. Inc., which is headed up by Russ Britt, president, has been making fencing, posts and rails from coast redwood. The company also produces a few specialty items, such as decking lumber and playground equipment components.

Charles Moyer has been the plant manager at Britt Lumber Co. for the last six years. He has worked in the forest products industry for about 40 years. "I started out in a moulding plant," said Charles. "I like the sawdust." For that reason and others, such as his great interest in the equipment that keeps sawmills and lumber remanufacturing lines humming, Charles stayed on the mill side by choice.

Britt Lumber Co. has made some significant changes during the last two years. In July 2002 the company added an Inovec StereoScan^TM 3-D contour scanner to one of the two Salem head rigs. "We liked it so well," said Charles, that an Inovec StereoScan system was added to the other Salem head rig in August 2003.

The company first decided to add the Inovec technology to increase production, not yield. "It was taking too long to load logs," said Charles "...eight to eleven seconds with the loader, now it’s three to four seconds." With the loading time slashed to half or a third, production naturally went up.

The first system showed remarkable results almost immediately. "It increased our production about 500 logs per shift," said Charles. The increase was noticeable in the first week the Inovec StereoScan was in place. Yield improved, too. "We picked up approximately five percent overrun," said Charles.

With the second Inovec StereoScan system, Britt Lumber picked up a bit more overrun, as much as 6%. "We increased about 150 logs per shift" with the second system, Charles said.

The second system was installed for the head rig handling larger logs. "We put the second one on for opening face," said Charles. The Inovec StereoScan accelerates the identification of the best log position for exposing the most desirable face.

The saw lines at Britt Lumber are divided. One line is devoted to larger logs and the other is fed smaller logs. The two lines emerge from one rosserhead debarker and bucking system.

Coast redwood bark is thick, fibrous and spongy. It can be more than 10 inches deep. (In living trees, the tendency of the bark to strip off is a characteristic that makes even coast redwood saplings easy to identify.)

Average log diameter is 10 inches. "We run eights, tens and twelves on the big side," explained Charles. "We run sixes, eights and tens on the small side." The small line can run up to 24-inch logs, and the large line can run diameters twice that big. Given that the mill processes only second growth redwoods, log diameters rarely get as large as those what the mill can potentially handle, explained Charles.

The Salem head rig used for smaller logs is paired with a McDonough 42-inch bandmill with stopping loaders and chains. The Salem head rig used for larger logs is paired with a Salem 5-foot bandmill that loads with a 17-degree slant. The setworks on the bandmills are equipped with Inovec YieldMaster^TM optimizing technology.

Charles’s knowledge of sawmill equipment derives from the many roles he has had. "I started out as a millwright," he explained, then "went to work as a forklift driver." He learned so much about the workings of machines at the heart of mills that he started designing them. "I’ve built a lot of sawmill equipment," said Charles, where he has seen a need and made what he needed.

Knowing sawmill equipment as well as he does, Charles appreciates equipment that performs well. "We’ve had very little trouble with them," he said of the Inovec StereoScan and YieldMaster systems.
"Every six months, a technician comes out and looks at them. It’s just preventative maintenance. We’re very pleased with the product."

The Inovec StereoScan 3-D scanning system speeds up an age-old process that the human eye alone once controlled. The Inovec StereoScan looks at and assesses the topography of the incoming log much faster and more comprehensively than can the most experienced human eyes.

The scanning system uses LMI DynaVision^TM L-4 laser scanners to complete a picture of the contours of a log’s surface. As the carriage travels toward the saw, the StereoScan offers a thorough look at the log. Laser lines projected onto the front and topsides of the log are viewed from two angles and 60 times per second with CCD cameras.

The virtual curtain drawn by the laser lines across the log and the way they are translated into information can be analogized. Imagine wrapping the log in a thin substance that hardens yet can be easily pulled away like a thin cast to reveal every ripple and knob. That is what the digitized picture looks like to the computer analyzing the data.

The Inovec YieldMaster headrig carriage optimizer uses the digital picture it receives from the scanning system to position the log quickly for maximum recovery. Because the StereoScan system works so fast, each sawn face can be scanned and the next position reassessed in real-time-- instead of a time-consuming process of turning and repositioning the log for visual inspections.

"It didn’t take any time at all to learn" how to use the Inovec equipment, said Charles. The four sawyers who cover two shifts also give the system good marks. "They’ve all liked the upgrade," explained Charles.

"The Inovec people were great," said Charles. "We did the hardware," installing the equipment and electrical service. "They did all the software and trained sawyers."

Indeed, it was the collaboration that Inovec provided from initial consultations that started the move toward optimizing the two head rigs at Britt Lumber.

"Inovec’s sales engineer sat down with us and went over the cost and recovery," said Charles. "He had a lot to do with it...our adopting" the equipment.

the story continues...

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