What the press says about LINCK

The best sawline worldwide?

Sawline in Tunadal redesigned
Swedish sawmillers are supposed to have an unwritten law: when a new sawline is taken into operation, it must surpass all former existing lines by far. The sawline of SCA Timber in Tunadal is currently casting its shadows far beyond Sweden. The feed speed of 200 m/min. is only one of the outstanding details.

The new T700 sawline of SCA-Timber in Tunadal is designed to produce 700.000 m³ of dry lumber per year. © Günther Jauk
Tunadal Plant Manager Katarina Levin and Linck Project Manager Daniel Betzold during start-up in Tunadal © Günther Jauk

„Sweden is just too small“, jokes SCA Tunadal Plant Manager Katarina Levin during the Holzkurier visit answering the question about the unusual location of the new sawline. For the large-scale sawmill project called T700, the company created additional 2ha of coast next to the northern Swedish town of Sundsvall. This embankment is indeed due to strategic and logistics reasons. The group has been conducting a spruce sawmill for a long time, using the affiliated SCA logistics company for the export. Over the past years, SCA invested 130 Mio € in the site including a planer mill, a sorting of dry lumber and a log yard. After having abandoned the initial idea to install the new saw line in the existing sawmill building while two other lines are producing, the paper and sawing group built a team of 30 persons. This team did not only plan a standard saw line but also questioned well established details of the plant. From now on, the operator has its workplace close to the circular resaw and suction of the saw line is done from below. The saw line is designed to process about 1.4 Mio m³ of round logs per year or to produce 700.000 m³ of dry lumber per year.

The cants pass the different processing steps at a feed speed of 200 m/min. © Günther Jauk

One minute is of great value
Katarina Levin pointed out that the maximum utilization of the round logs at lowest possible production costs were the top priority during the planning stage. As the new saw line had to replace three existing lines, high feed speeds, small log gaps and a high plant utilization were imperative. A feed speed of 200 m/min. means 50 logs per minute or in other words: a machine has got less than two seconds for the corresponding processing step. “It is not sufficient to simply use stronger motors in order to achieve this pace. The whole line must be adapted“, explains Daniel Betzold of Linck. He was responsible for the planning of the profiling line. This adaption was already met by the installation of a third pair of rotating roller instead of the commonly used two pairs. „This way, the line has more time to rotate the logs into the optimum position for sawing according to the scanner data.” Furthermore the logs/cants are held in place on the whole line with an unscheduled stop of the latter and the roller conveyors are stopped by means of a fast braking system – measures which are imperative with such high feed speeds.

Taken from the paper industry
SCA took over some of the installation features from the paper industry. This is why the line is connected to a voltage of 690V and not to 400V as it is usually done in Europe. The higher voltage provides the same output at lower power consumption. Linck had to adjust its motors; however wiring could be carried out with considerably thinner cables. The permanent monitoring of all tool shafts with regards to temperature and impact loads is also a feature from the paper industry. The recorded data is transmitted to the status monitoring department of the sawmill group which in the future can forecast probable damages and calculate maintenance intervals. Tunadal is the first sawmill worldwide to use this system.

Suction pipes were on the spot converted to injection pipes; the air aspirated from below is filtered and recirculated. © Günther Jauk

Less dust in the sawmill building
Even the suction concept is completely new. The exhaust sockets are now placed underneath the machines. The force of gravity leads the dust particles through the saw floor into a cyclone filter where they are captured. The former suction pipes then blow the clean air back into the sawmill building exactly to the machines. This circulation channels the dust particles in one direction and warm air is resupplied to the building.

Where are the grease nipples located?
Grease lubrication does not happen at centralized lubricating points outside the safety fence but from a central lubricating point only. "This means considerably more time required and higher costs for installation, however resulting in substantial time savings and less personnel required under operation", explains Betzold.

The noise absorbing sawmill floor of CLT (cross laminated timber); each cable had to be designed accurately a long time before installation. © Günther Jauk

Sawmill floor of CLT
Also the sawmill building is far away from being ordinary. The sawmill building standing on 800 concrete columns on an area reclaimed from the sea is generously dimensioned. The building is 150 m long (without the log feeding station) and the sawmill floor of cross laminated timber lies at a height of 6.5 m. „SCA opted for CLT due to the better sound and vibration absorption”,says Betzold. And indeed it seems to be much quieter in the sawmill than usual. SCA dispensed with the obligatory view on the whole sawing line from the control cabin. Instead, the operator was placed next to the saw sharpening room and the circular resaw. This is where he/she most frequently has to change the tools and is moreover not far from the remaining staff, justified SCA.

„We take our time“
The first log passed the Tunadal sawline mid of April. The optimisation phase is currently running for which SCA scheduled enough time. „We deliberately take more time for commissioning, but then our personnel is well-trained and the sawline fine-tuned “, informs us T700 Project Manager Jimmy Hörnström. As long as the sawline is not operating at full capacty, the three old lines are producing the missing quantities. Almost at the end of the project, SCA and Linck are very proud of their achievement. Mr. Betzold talks about a successful project and one of the greatest challenges Linck ever faced. SCA even speaks of „the best sawmill in the world“.