Maximizing value through vision scanning
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value and recovery out of those logs. “We selected USNR because we believed the BioVision system could fulfill our requirements.” The Taupo operation comprises a complete sawmill, dry kilns, planer mill, and secondary processing plants. The site processes Prune Butt logs into appearance grade products including lumber, solid lineal mouldings and clear pine boards.
At Taupo, logs are a mix of sizes ranging in diameter from 35cm to 950cm. The supply begins with a radius back unscrambler feeding a turn/pass station and lug loader that is monitored from above utilizing USNR’s MillTrak system for flow and backlog control. The boards pass through the transverse scanner and on to the Maximizer positioning infeed table where they are rapidly fed into the 5-saw edger sawbox. The edged boards exit the process via USNR’s Flying-V Tailer, with tailings separated to a waste belt below. The sawbox selected for this application utilizes 5 saws and a shifting straight edge with hold-over shoe. This allows the mill to process splits with one saw, and no edgings. Darryl commented, “We basically run slower than what the machine is capable of running. When we run wide boards we want to be absolutely sure the solution recovers the highest value. We can cut up to about 100 mm thick, and every shift has a different cut ranging from 5/4, 25mm, 50mm, 65mm, 77mm, etc. It varies all the time, and that was the idea for choosing the 5-saw machine.”
The sensor the Tenon team chose with the system is the BioLuma 2900LVG. This sensor is a powerhouse for collecting high density data from geometric measurements and visual characteristics, to grain angle measurements. It is the only sensor on the market to integrate this range of technology within a single sensor housing. It is, without a doubt, the best sensor on the market for the job of collecting the vast amounts of data required for accurate and precise defect recognition and analysis on green lumber.
The layout – Tenon and Skookum connection
Designing the layout for the system didn’t come easily. Kaki Waenga, Tenon Project Manager, noted: “The concept changed several times. Tenon’s project engineering team working with operations personnel, reviewed a number of layouts with Skookum Technology. We initially tried to insert the new Edger line within our existing building footprint.” The final design came from the Tenon project team, situating the Edger next to the existing production line, which proved to be a very strategic move and paid large dividends in time management and commissioning. That’s where USNR’s agent on the ground in New Zealand, Skookum Technology, came in. Skookum’s General Manager, Geoff Strang, relates: “Skookum assisted with the original project feasibility study, and worked with Tenon over a period of time specifying and determining the best layout for the new edger line.”
Darryl related the benefits that Tenon has achieved. “We’re getting an increase in log to lumber recovery, more than we initially expected, so we’re really pleased with that. Also the system allows us to do a lot more rationalizing of products to improve efficiencies in our secondary processing.” He also noted the project delivered all the benefits outlined in the original scope and was delivered on time. “The board edger was a game-changer for us. It’s changed the bottleneck in the sawmill. We can put more wood out of our facility, we’ve increased our throughput, now we’ve got to look at the rest of the mill and speed that up to balance mill flow.” Today, Tenon’s needs for improved recovery and throughput have been more than satisfied with their technology choice. Tenon describes the operation as the country’s largest single site producer of defect-free, appearance grade radiata pine products. This new edger line, with its BioVision grading capability, dovetails nicely with the company’s goal to expand and grow its output and its market, and to maintain its standards for the utmost in quality products. USNR has long been a front-runner in advancing this technology, and is proud that the strong relationships it has forged with customers like Hyne Timber and Tenon have allowed it to provide the tools our customers need today to meet their goals.
Tenon-edger-infeed 2: As flitches are transported through the scan zone the image and applicable defect data is displayed on the user interface screen.
Defect: This piece demonstrates the value equation utilizing edger BioVision. The top screen solution uses visual defect optimization compared with the bottom solution which uses laser profile data only. Having the optimizer switch the position of the 100mm product, the mill is able to obtain a higher grade board.
845-screen: The BioVision optimized decision shows a 2-board solution; 1. is a #3 Shop 5/4 x RW, 150 mm wide x 3.6 m long. 2. is a #2 Shop 5/4 x 145 mm wide x 3.6 m long. The interface also shows such details as saw positions, recovery volume and value, list of cuttings from each board, etc.