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November 2006 - The Logging and Sawmilling Journal

 

SAWMILL TECHNOLOGY

OPTIMIZING BREAKTHROUGH?

Sound technology could well be the next optimizing breakthrough in Canadian sawmills, and two New Zealand companies have already made significant advances in this kind of technology.

By Tony Kryzanowski

Will sound waves—a nondestructive approach to predicting the strength properties of both logs and green lumber—be the next big optimizing breakthrough for Canadian lumber and veneer mills?

That could very well be the case, and two New Zealand-based companies, Fibre-gen and Falcon Engineering, have already made significant advances in sound-based technology as forest resource assessment and sawmill optimizing tools. Fibre-gen’s technology is being used in sawmills processing Radiata pine and other species in Oregon, Australia and New Zealand.

Two New Zealand-based companies, Fibre-gen and Falcon Engineering, have made advances in developing sound-based technology as a sawmill optimizing tool, which would give sawmills a non-destructive approach to predicting the strength properties of logs.

“How we will benefit most is that it will give us more of an indication of out-of-grade, green lumber so that we are not processing lumber that we’re not going to be able to convert into high value products,” says Darryn Adams, site manager at a Carter Holt Harvey (CHH) sawmill at Putaruru on the North Island of New Zealand. CHH is the largest vertically integrated forest company in New Zealand, and this sawmill produces structural, treated, and visual grade lumber.

Having the ability to sort out inferior grade structural green lumber in a nondestructive way using sound could be an important breakthrough for Canadian sawmills. This is especially true given the high cost of energy to operate dry kilns. Should the technology prove effective, it could help companies gain more assurance that the energy they are using to dry their lumber is actually being applied to lumber that will make or exceed grade specifications. In effect, they will be getting more bang—in terms of high value lumber—for their energy buck.

Combined with moisture detection and machine stress rating along the value chain, sonic testing could represent another bullet in the industry’s arsenal to squeeze more value from every log at the lowest possible cost.

Falcon Engineering is marketing a product called the A-grader, which was originally developed by New Zealand and Australia’s joint forest research institute, Ensis.

Used to determine the stiffness of timber using sound waves, the A-grader can be applied to green lumber, kiln dried lumber, or long and short trim blocks. At present, it is being used to: sort green rough-sawn, random size, and random length lumber on the green chain; to grade finger-joint blocks based on stiffness; for density sorting to create more homogenous charges going into the dry kilns; and for stiffness grading on random length dried and graded structural lumber.

It is capable of stiffness grading boards at production speed. The A-grader was demonstrated at this year’s New Zealand Forest Industries Expo.

Fibre-gen was also present at the Expo and has been a pioneer in the development of acoustic-based log and lumber optimizing tools.

“Our tools are being used to fine tune all along the value chain, so that when the lumber goes into the bin sorter, we can pretty much say that these green boards with that particular modulus of elasticity (MOE) will give you 80 per cent of a particular grade and MOE dried,” says Peter Carter, Fibre-gen’s resource technology and commercialization manager. By capturing this type of information so early on in the manufacturing process, business managers can also better predict what quantity of certain types of products the sawmill will generate by the end of the process.

Combined with moisture detection and machine stress rating along the value chain, sonic testing could be another bullet in the forest industry’s arsenal to squeeze more value from every log that comes into the mill yard.

Unlike many other technology companies that start from ground zero with a strong idea and lots of hopes and dreams, Fibre-gen evolved within CHH as a research and development division of the forest company. It was one of the first organizations to investigate the potential of using sound-based optimizing tools and to have actually successfully implemented the technology. About four years ago, Fibre-gen got permission to sell its products externally, which included CHH’s nearest competitors. Now the company’s portable and stationary soundbased tools are used widely throughout Australasia, as well as at a few veneer mills in the United States.

Recently, Fibre-gen was being considered as a spin-off candidate by CHH as part of a major restructuring taking place at the forestry giant, which was half owned by International Paper (before it announced that it was exiting the lumber manufacturing business). CHH is now owned by New Zealand’s richest man, Graeme Hart, who in October completed a major deal for some of the company’s forestlands.

The deal saw American timber management organization Hancock Timber Resource Group buy the 275,000- hectare (687,000-acre) Carter Holt Harvey forestry estate—estimated to be worth $1.55 billion—for an undisclosed sum.

As part of CHH, Fibre-gen’s technical researchers had the luxury of analyzing various ways that sound waves could work in a non-destructive way to gather quality information throughout the value chain, including the forest resource. The company’s hand held tools have proven invaluable to assess the strength properties and characteristics of standing timber, which is a critical issue in New Zealand because its forest ownership model resembles the private ownership model used in the United States.

By using handheld acoustical tools, mill owners can assess the timber resource offered for sale by forest owners in a non-destructive manner, and negotiate payment based upon that data.

In Canada—where forest companies own harvesting rights to large timber resources—using handheld acoustical tools could help to gather data on the overall strength properties of trees within cutblocks being considered for harvesting or to assess fibre quality in those instances where private wood is being offered for sale.

Where Canadian companies could gain significant potential value in this technology is for evaluating veneer logs. By using acoustical testing of peeler logs at the mill entry point, it is possible to determine the best peeling pattern to capture the highest volume of higher strength veneer, and to sort logs with similar characteristics into the same bins. Roseburg Forest Products in Oregon is sound testing its peeler logs for density after the debarker—but before the chop saws—to assess log quality prior to peeling.

Sorting logs at the infeed has already been recognized by many Canadian mills as one way to maximize recovery and value from the overall forest resource. Sonic testing may offer a cost-effective alternative for sawmills that don’t require the level of detail offered by 3-D scanning.

By using sonic testing and capturing more information early on in the manufacturing process, mill management could better predict what quantity of certain types of wood products the sawmill will generate by the end of the manufacturing process.

The CHH mill in Putaruru is sound-testing logs entering its sawmill, but Adams says that at present the information being generated by Fibregen’s device is simply being used to collect data to construct a profile of the log diet entering the sawmill.

In terms of penetration into the Canadian market, where the trees tend to take at least twice as long to reach maturity as New Zealand’s dominant conifer species, Radiata pine, Carter says Fibre-gen’s acoustical technology has shown itself to be adaptable to a variety of species. Fibre-gen has worked with Forintek, Canada’s forest products research institute, to show that the technology is legitimate and appropriate for the Canadian market.

Where it becomes a bit challenging is when sawmills have a variety of species with varying densities entering the sawmill.

“The conversion of green density to dry density will be different for different species,” says Carter, “but that is predictable on a species by species level.” He notes that many Canadian sawmills already sort out less predictable species like balsam fir and that the density characteristics of the remaining spruce and pine species are very similar.

 


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