Perceptron Scanning and Optimization Technology Applied to Bucking, Log Rotation and Break-Down
DODSON, Louisiana — Willamette Industries is known for its strong commitment to conserving natural resources. Its policy is to operate in a manner that ensures good stewardship of the environment and provides long term benefits to the local community and Willamette shareholders.
The company’s policy was an important factor in its decision to upgrade a Willamette mill in Dodson, Louisiana, a project that was recently completed. According to mill manager David West, the improvements significantly expand the ability to respond to the vagaries of the marketplace. Investments in new technology also increased fiber recovery — providing important benefits for both the company and the environment.
The mill, last modernized in 1993, now has a fully optimized production line. Processing equipment from a number of different suppliers was closely integrated with scanning technology to enhance both the quantity and the value of the mill’s products.
The centerpiece of the new equipment was an Optimil band mill for primary breakdown. It was integrated with Perceptron scanning and optimization technology to maximize fiber recovery and value.
The improvements represented a substantial investment for Willamette, David noted, but the investment was necessary in order to meet the company’s goals for environmental responsibility, fiscal stability, and its commitment to the people working at the plant.
The new mill was designed to allow Willamette to make better use of the resource than had been possible previously, especially in terms of adjusting product mix to match market conditions. “The new mill gives us tremendous versatility in an ever-changing marketplace,” said David. “That’s the area were we saw the biggest improvement.”
The company started with improvements to the log storage area. It put in a 110-foot JC 40 Electrocrane that has 40,000 pound lifting capacity and a 120-foot outreach. The old mill processed pre-cut logs ranging from 20 feet to 40 feet long. The new mill handles tree-length stems that are generally between 30 feet and 60 feet long. With the new crane, logs can be stacked in a circle to a height of about 55 feet, allowing for a much larger inventory.
About 40% of the logs processed at the mill comes from Willamette’s own forests. The remaining 60% is purchased at the gate or is timber bought from private lands where Willamette contracts for harvesting. Some harvesting is done by Willamette’s own crews while some logging is done by contractors.
The first step for the logs is a Nicholson A7 ring debarking system, which prepares them for the Perceptron optimized USNR bucking system. Debarking has become an important part of a modern mill operation, David noted, because thorough debarking is critical in achieving maximum optimization. If the bark is not thoroughly removed from a log, the scanning process will not be as accurate, nor the milling solution. The result will be a log that is not processed for its optimum value. “With the new debarker, we have seen a big improvement in the quality of the log when it arrives for breakdown,” said David. “We’re also getting a better quality chip out of the system. All that means we’re getting that much more out of the log when it is processed.”
Primary breakdown is accomplished on the Optimil double-length end feed, two sided band mill. It is paired with Perceptron scanning and log optimizer for both auto-rotation and log breakdown.
At the Optimil, material that is not suitable for producing lumber from a value standpoint is chipped to form a two-sided cant. The Optimil system features ‘slew and skew’ technology, which allows for the log to be scanned again when it is in the infeed. With the ‘slew and skew’ ability, the machine makes small but significant adjustments to fine-tune the approach of the log. The technology improves recovery by 1.5%, according to Bill LeGentile, Optimil’s sales manager.
Despite the complexity of the milling equipment, it is also very fast. Willamette, operating on a 10-hour shift, is pushing about 36,000 feet per hour through the plant.
An important benefit of the new optimized bucking and primary breakdown systems is the ability of management to adjust log processing to the changing needs of the marketplace. “We’re able to plug in data we get from sales, and then let the Perceptron equipment look at the logs we’re inputting and calculate how the best value can be achieved from them,” said David.
In a volatile market, David noted, the ability to plug in sales figures and make milling adjustments is a huge factor in maintaining profitability — and stability for the mill and its employees. One week, for example, 2×4 material cut to 8-foot lengths may provide the best return on fiber coming into the mill. If the market changes, 2×12 may be more profitable or 2×4 in 16-foot lengths. “When the market changes, we’re able to input those changes into the Perceptron, which controls the saw systems and allows for the best blend of products coming out of the mill,” said David. “That kind of versatility is very important to us.”
Cants produced at the Optimil are transferred to a CAE double-arbor gang saw with curve sawing ability. Rough boards exiting the gang go to a CAE Robo edger. Both units utilize CAE scanning and controls to maximize value.
After edging, lumber moves to USNR optimized trimmers, through a drop sorter system, and on to a USNR automatic stacking system for placing kilns sticks and preparing the material for drying.
Lumber is dried in Wellons steam-fired dry kilns. After drying, the lumber goes to a planer mill that has been in place since 1993. The planer mill utilizes an infeed by USNR to move the lumber to a Yates planer and then out for packaging and shipping.
The improvements Willamette made to its mill in Dodson conform to the company’s priorities: get the maximum value out of the resource and waste nothing. The investments in new technology are important both to Willamette and the community its serves, according to David, because they benefit the environment, enable the mill to produce a wider range of products more efficiently, and bring stability to the mill and the jobs it provides.
“At this plant, 100 percent of the log is used,” said David. The benefits of eliminating wasted fiber are fairly self-evident, he noted. Logs are optimized in order to process them into the highest value lumber in the greatest volume possible. The mill’s by-products also are utilized for their highest value. Fiber not suitable for lumber is processed into chips for paper production. Sawdust and other residuals are used in Willamette’s particleboard plants. Material not suitable for either use is incinerated to produce 100% of the steam required for the dry kilns and also steam for conditioning and the adjacent plywood plant; using residuals for fuel to generate steam reduces the mill’s reliance on electrical power and fossil fuel.
The mill is not unique among Willamette facilities in utilizing wood waste as an energy alternative to fossil fuels or electricity, David noted. Willamette’s policy is to use the best technology available to run its plants in an environmentally responsible way. The federal government is encouraging the use of wood residuals for fuel as a component of policies to reduce greenhouse gases, so Willamette’s technology helps to achieve those policy objectives and benefit society. Company-wide, Willamette supplies 61% of its own energy needs through a combination of using residuals for fuel, pulping liquors and co-generation.
Optimization has become not only a vital component of a modern sawmill’s profit picture but also a significant factor in providing environmental benefits. Optimil estimates that the projects it has completed in just the last three years have resulted in annual wood fiber savings equal to more than 15 million logs.
For more information about Percepton scanning and optimization technology, contact Perceptron at (734) 414-6100, fax (734) 414-4700, or visit the Web site at www.perceptron.com.