Sustainability-driven saw line
Tropik Wood increases recovery to support building boom
Approximately 2500 Fijians, including the country’s Prime Minister, celebrated the startup of a new Söderhamn Eriksson/
USNR sawline at the Tropik Wood’s Drasa mill in Lautoka, Fiji. The new equipment replaces an old sawline and almost doubles the mill’s timber recovery.
Founded in 1987, Tropik Wood Industries Limited (Tropik) is the largest producer of timber products in the country. Processing Caribbean pine, the 170-employee company produces more than 15 product types, both treated and untreated, ranging from profiled timber, construction material, and posts and poles for domestic customers, to wood chips for export markets. Waste material feeds a biomass power generating plant.
The mill was using equipment purchased in 1987 that focused on volume rather than recovery.
This did not match the company’s and the government’s goals for optimizing the use of the island’s natural resources.
Four years ago, Tropik decided that major capital upgrades to their sawmill line were needed. “The old mill experienced long downtimes and very poor recovery,” said Vimlesh Kumar, Tropik Wood’s Project Manager. “The low average recovery of 27% meant that we were wasting our valuable saw logs, which take 25 years or more to mature for timber.”
Tropik considered several alternatives including buying refurbished machinery from Canada or New Zealand, but opted for new, top-of-the-line equipment for greater certainty of productivity increases over the next 15 years.
The process: Debarking
Caribbean pine logs enter the sawmill unsorted leading with the small end. Logs range from 15 - 50 cm diameter in lengths of 3 - 6.1 metres. Logs are scanned and optimized, with 2.8 - 3 m gaps at the infeed. Processing logs with small ends first provides advantages in more accurate infeed alignment and for edging accuracy.
Logs enter the debarking line at consistent intervals. The Cambio 800 is a heavy duty high-speed debarker that accommodates all log sizes, and is particularly suited for logs up to 795 mm in diameter. It offers reliability, minimal service requirements, and ultra-low operating costs. Triangular feed works and carbide tipped debarking tools actuated by compressed air are important features to achieve first class debarking results.
Tropik Wood paired the Cambio
800 with the CIM Debarker Infeed. This infeed’s auto-centring function feeds logs with no gaps, maximizing debarking line productivity. The CamTrail debarker outfeed prevents logs from wobbling or rotating during the process. Once debarked, logs pass through a metal detector, to a log kicker, elevator, and singulator, then on to the sawline scan conveyor.
The process: Chipping, canting
Once scanned, a 3D data model is produced and the optimized saw pattern provides log and cant breakdown solutions. Log rotation is achieved with the 750E rotary log turner controlled from the PLC and actuated with an electric servo motor.
Next, the LogPos infeed positions the log with 4 pairs of vertical side rollers on a chain bed. The side rollers have spikes to hold the log’s rotated position securely while feeding into the cutting tools. The infeed offers side shift capability of ±30 mm and follows the path defined by the sawline optimizer to achieve accurate opening faces on both sides. Spiked rolls firmly secure and feed the logs into the chipper canter unit.
The Chipper Canter with CombiSpiral discs was chosen because it produces first class pulp chips, and boards with smooth sawn faces and proven dimensional accuracy. With a wide variety of accessories, it can be customized for log or cant breakdown, straight or sweep sawing and for production speeds up to 150 m/min.
The process: Sawing
The quad bandsaw maximizes production and performance with thin kerf saws. It is designed for high product accuracy at feed speeds up to 120 m/min. Two to four sideboards are separated at the board separator, and dropped onto the edger conveyor.
The cant is turned 90 degrees and conveyed to the Cant Feeder 435 which positions it in front of the second chipper canter; it is centered, side shifted and skewed for the most accurate curve sawing following the cant’s natural shape.
The curve sawn cant enters the single arbor circular saw with 4 shifting saws and the option to mount additional saws on the outer shafts. Side and center boards are sent to the green chain. Side boards are manually separated and sent to the optimized edger.
The process: Edging
The Catech 400 edger line includes an S-shaped unscrambler, transverse scanner with conveyor, edger infeed and 3-saw edger, edgings separator, and board outfeed. The edger line offers high speeds and top recovery with optimized wane control, and a split saw for processing wide boards.
One of the challenges we faced was integrating new equipment into an old facility with in-place infeed and green chain. “The costs of moving everything would make the project commercially unviable,” said Faiz Khan, Fiji Pine’s Executive Chairman. “To increase our chance of success, we engaged the services of Skookum Technology, the process engineers (and Söderhamn Eriksson/USNR’s agent) out of New Zealand, to review our plans and ensure a smooth machine installation.”
“Another challenge was the isolation factor,” said Vimlesh. “It takes almost two months for shipments to reach Fiji from Sweden.” As if these challenges weren’t enough, a major cyclone hit the island in the middle of the project. “Despite these factors, and the time zone difference between Fiji and Sweden, the project was implemented on time,” said Vimlesh.
The new mill has a capacity of 350m3/day, however, it is currently being run at a daily average of 180m3 to ensure sustainability of the island’s forests. As a result of the new equipment, timber recovery has increased significantly. The new line also offers greater flexibility and can handle larger diameter logs.
For Söderhamn Eriksson/USNR, this was a unique and challenging project. Lars Lindvall comments: “We knew this project was going to have significant challenges, but we were pleased to be able to outfit this operation with state-of-the-art equipment that will serve Tropik’s interests for many years to come.”
A flitch is fed into the Catech edger machine.
Logs are rotated with the 750E log turner as they enter the LogPos positioning infeed for secure feeding into the cutting tools.
Cambio 800 debarker with CIM 750 Infeed.