Dart Hits New Market
Summary: Ainsworth Lumber's new finger-joint plant at Grande Prairie is using the first Australian-developed DART grading machine seen in North America.
By Tony Kryzanowski
A key piece of equipment at Ainsworth Lumbers finger-joint plant at Grande Prairie, Alberta, is a DART Machine Stress Rating (MSR) device the first of its kind in North America. Its function is to accurately grade lumber strength at high speed. There will obviously be comparisons made between this Australian-built DART and the North American industry standard for stress rating lumber, the Continuous Lumber Tester (CLT).
Manufactured by Washington States, Metriguard, there are more than 100 CLTs in North American mills; the product trademark has, for sometime, become synonymous with the machines function. Mills install lumber-grading machines when they need to validate the strength of their lumber products. If the mills lumber ends up as roof trusses or laminated beams, knowing the lumbers strength is critical. Ainsworth plans to buy low-grade lumber from other mills, pass it through the DART MSR, determine each boards strong points, cut theweak points out, and finger-joint the strong sections together.
They then plan to send the finger-jointed lumber backthrough the DART MSR to grade it. So far, Ainsworth is the only North American mill to install a DART MSR, and they are satisfied with its performance so far. Ainsworths value-added manager in Grande Prairie, Don McGladdery, formerly worked at their finger-jointing plant in Abb o t sford, BC. He is familiar with the CLT and feels that the DART isa better product. I like it because of its simplicity andbecause it is user-friendly, he said.
Its a heck of a lot easier to use than the alter-n at ive. There are less moving parts, and its easier to run. McGladdery says what Ainsworth has in mind may be a glimpse into the future, aswood supplies diminish and trees get smaller. As a matter of survival, mills may find themselves trying to gain maximum usage of all manufactured lumber. For example, by todays standards, an inferior 2X4 with a strong section winds up in the trash heap. If what Ainsworth has planned works, they may open the door to an entirely newapproach to salvaging inferior boards.
Part of the problem with the process of grading finger-jointed lumber is that there has not been a grading device available in North America capable of testing its strength. The National Lumber Grades Authority in Vancouver has established aspecification of SPS4 for finger-jointed lumber, but they cannot find a machine capable of conducting an accurate test.
Should the DART succeed in reliably grading finger-jointed lumber to an SPS4 standard, that could open entirely new markets for finger-jointed products. David Orames, North American marketi ng director for Eldeco Industries , worldwide distributor of the DART MSR, says standards experts need to conduct more research using the DART to gradefinger-jointed lumber. But its physically possible. We can do it, he adds.
Orames has no doubt that the DART is a superior machine. Its advantages are that it is considerably smaller and has less moving parts to accomplish the same task. It is only 8' long, and has only five sets of rollers. Rather than a complex set of rollers needing regular precision adjustment, the DART works on simple principles.
As the lumber enters the machine, it passes through a set of rollers that bend it in one direction, said Orames. As it emerges from those rollers, it passes through another set of lighter rollers that measures the natural bow. The computersubtracts one bow from the other and measures the strength on that basis. Orames says technology similar to the DART has been around in Australia since the 1960s.
The originating manufacturer sold about 100 of the machines to mills in countries including England, Ireland, Australia and New Zealand. In 1986, one of the mills approached Eldeco, at the time specializing in electrical engineering, to see if the firm could fix an old 1960s model . According to Orames, they did so and, intrigued with the technology and learning the machine was no longer in production, decided that a redesigned version would find a market.
We designed a new machine that hasthe same physical operation and the same geometry, but with the latest technology, such as computer controls, load cells and encoders. The new machine was launched in 1988and 16 have since been installed in Australia. Marketing has now begun around the globe. Orames, originally a partner in Eldeco, recently relocated to Canada.
He blames his inexperience with North American institutions for delays in getting a DART certified so he could take it to the market. It took a year to get a machine over here and to find somebody to do the testing for me, he explains. Finally, he organized a test session with a representative from the National Lumber Grades Authority at the University of British Columbia.
The machines accuracy shocked him, says Orames. He (the representative) took one 2x4 at random and passed it through the machine and he recorded the strength reading off the digital screen, says Orames.
Then we turned the stick around and put it through again, and then end for end. We put it through each of the four ways, and got the same reading each time. Then they tried a 2X6, which caught Orames somewhat off guard. He had 100 2X4s for test purposes, but no 2X6s. They managed to track one down at UBC.
Unfortunately, the DART MSR gave dif-ferent readings when the 2X6 was passed through in opposite directions. As a result, the DART MSR was only certified for sizes less than 2X6. Orames says that one piece of 2X6 is hardly a representative sample. He hopes to conduct tests on larger lumber at Ainsworth.
Australian mills grade lumber up to 2X12 on the DART without any problems, he says. The DART MSR will grade 1,200 board feet per minute flat out and requires minimal maintenance, says Orames.
He says many Australian mills have connected their machines to a computer to monitor it remotely. There are two main differences between the DART and the CLT. The DART accepts wood on edge, common in mills everywhere except North America. This requires North American mills to construct a waterfall-type conveyor system to take boards laying flat from the planer to laying on edge prior to entering the DART. The CLT accepts wood on the flat plane. To some extent, this diminishes Orames claim that the DART takes up less space, since mills feeding directly from a planer will have to install a waterfall-type conveyor system.
Also, Metriguards most common larger model is considerably faster, grading boards at 2,000 feet per minute. But there are considerable cost savings comparing these two units. The DART sells for about$150,000, estimated at about half the cost of the faster CLTs. Metriguard has a newgrading model available, at a price within the price range of the DART. While the cost and installation are a savings are debatable, the DART s simplicity and user-friendliness, as describedby Ainsworths McGladdery, is self-evident. The DARTs design makes it adaptable to new applications, such as the growing 105-mm by 105-mm market developing in Japan. All that is required is a redesign of the DART s throat and a more powerful airbag device to grade larger wood. Ainsworth will begin production of finger- jointed studs, I-beams and window stock later this year, aiming for distribu-tion into the North American market. Orames expects considerable demand for the DART MSR as Ainsworth begins production.
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