-- Sawmill Upgrade --
Phasing in... High Tech
Northwoods Rustad sawmill in Prince George, BC recently completed the first phase of a $33 million improvement program.
By Jim Stirling
An innovative small log canter line at Northwood Incs Rustad sawmill in Prince George, BC is delivering on its promise of higher lumber recovery and at the same time positioning the operation as a competitive producer in an increasingly crowded lumber market.
The $10 million high-tech, high-speed line allows the aging Rustad mill to pro-duce more quality lumber products from each log entering its mill yard. Controlling high log costs is seen as critical to the success of Northwood and other BC lumber producers, who are all understandably interested in keeping a competitive edge in the global marketplace.
Investment in the new small log line is the first phase of Northwoods $33 mil-lion, five year capital spending vision for the Rustad mill. The goal of the improvements is to return the sawmill into the ranks of being a top quartile producer, says Pat Donnelly, Rustads plant manager.
Control is a key feature of the new line. It has the ability to capture and press small logs straight, and process them at speeds of up to 1,000 logs an hour. Accomplishing that while achieving the goal of significantly improving recovery and enhancing chip quality has required a collaborative effort between the Rustad team and its major equipment suppliers. The intent is not to increase production per sethe mill produces about 265 million board feet of lumber a year in Japan grade and shop gradesbut to improve the plants small log processing, and reduce machine centres, adds Donnelly.
The small log line handles material 7.5 inches and less in diameter. The process begins outside the main sawmill building with a four saw slasher system. Spruce, pine and fir logs up to 61 feet in length are prepped for eventual conversion to lumber in eight to 20 foot lengths. Aseries of conveyors with variable frequency drives feeds logs toward a new 17-inch single ring Nicholson A-5 debarker. The first-of feature here of note is a 20 foot centering conveyor feeding the debarker. The idea is to gain control of the logs on the conveyor and feed them through the conveyor butt to butt, says Donnelly. He credits Nicholsons receptiveness to designing the centering infeed for meeting Rustads requirements.
The system is capable of speeds of 425 feet/minute but more typically runs at 350 feet/minute. Their record through the debarker has been 8,276 logs in an 8.5 hour shift, says Donnelly. Efficient bark removal is important to Rustad since it is a chip supplier to Northwoods pulp mill in Prince George. "Were consistently in the 106 to 107 per cent quality bonus range."
Debarked logs are sorted by diameter and directed accordingly to either of two infeed lines to the new small log line or the number one Chip N Saw breakdown line. Each bin has a Linden step feeder to deliver logs singly into the processing line.
The USNR-supplied line is 56 feet long with a double length infeed positioned by a U-frame system. It allows logs to be moved on both axes in any direction around an approximately three inch square. USNR calls it the SST small log canter line: slew, skew, tilt. "It has a very smooth operation" notes Donnelly. Porter Engineerings S-type motion controllers position the double length infeed and a Porter RT3 scanning system assesses the true shape characteristics of each log.
One of the critical things for the mill was to capture the logs and trap them while being pressed flat, explains Donnelly. Rustad staff worked closely with USNR to incorporate features into the design of the line. Rustad consultant Ernie Redford, electrical supervisor Bill Loehndorf, sawmill superintendent Glen Connell and Donnelly headed the companys team. "USNR were very receptive. A lot of creative ideas were generated on both sides," he adds.
Rustad wanted to process the bottom face of each log flat with no spline on the drum head to maximize recovery. The canter also uses a drum top head and disc side heads. Aspecially designed fluted plate in the heads and side press rolls provide real-ly good control during the cutting process, continues Donnelly.
Ease of maintenance is another design feature. The bottom drum head pulls all the way out for simple knife replacement with the top head accessed by a trap door. All the heads have variable frequency drive Baldor motors supplied by Arrow Speed Controls to maximize chip values. Donnelly says the line has run at 700 feet/minute but is settling in nicely at around 550 feet/minute. "It is peaking at 1000 logs/hour with a record to date of 8500 logs in an 8.5 hour shift."
Cants proceed to an on-line six-inch vertical double arbor USNR edger. It uses information from the canter to activate its two clusters of saws. It was cutting with .120 inch kerf and achieving a very solid total deviation between 0.004 and 0.005 inch. The edger has large doors for easy access to saw changing.
Concrete work started on the new USNR line in October, 1998, and it began its start-up mode during the Christmas shutdown. Donnely says its been a smooth process, with Rustads crews becoming steadily more familiar with the new lines equipment.
Stolberg Mill Construction was the engineer on the project. B.I.D. Construction of Vanderhoof was the primary contractor, while Central Installations of Prince George handled the concrete work, including the concrete pedestals providing the required stability for the new line. Milltron Electric of Prince George was the electrical contractor.
Other notable upgrades took place prior to installation of the USNR small log canter line. Two new Newnes edger optimizers with laser scanners were fitted on line. Laser scanning provides superior accuracy, further improving recovery, and adds the ability to better position boards to produce higher valued products. A Coe trimmer optimizer was added ahead of the J-bar. Anew hog sys-tem at the mill will help Rustad achieve an eventual phase-out of its beehive burner. BC mills are under notice to develop alter-native ways to dispose of wood wastes.
Planning continues for the second major phase of Northwoods five-year capital spending program at the Rustad sawmill. The main thrust will be replacing the Chip N Saws used to process some of the mills diet of larger logs. An outfeed kick-off section has been installed downstream of the canter before material enters the VDA edger. This section will be activated during the second stage of the rebuilding pro-gram. It will provide the ability to kick sideways smaller log diameter categories that have not been adequately held flat while passing through the canter. They will be diverted to a curved sawing gang edger.
The new small log line and the other phased improvements still to come represents good news to the more than 300 people employed at the mill. It means a level of job security. And it underlines a commitment to keeping alive the 55-year Rustad tradition for producing quality wood products and flourishing in world markets.
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