Yield and flexibility

The sawmill equipment for Viiratsi unites the best Swedish band-saw tradition with scanner and optimization solutions of parent company USNR. This is one special feature. The other are the very clear-cut and concrete ideas of the Nordwood team around CEO Tõnu Ehrpais: "Roundwood here is expensive and scarce. We must get the highest possible yield out of every log. For this, we need the perfect optimization that manufactures orders as effectively as possible. In our sales department, you can order virtually everything in millimeter increments. This calls for a very flexible cutting line."

All three Nordwood sawmills, therefore also Viiratsi, are operating Hewsaw lines from Veisto. They are specially designed for smaller roundwood dimensions. "This is why we started thinking about including large-dimension timber as well in the future. If we can buy all parts from forest owners – from pole timber to heavy timber – this creates clear purchasing advantages for us."

Everything – from 8 to 60 cm

The solution that Nordwood was imagining and subsequently was given shape by USNR looks like this now: Small-sized timber (8 to 18 cm) is processed on the existing Hewsaw 200 SE. Everything beyond that up to 52 cm head log or 60 cm at the large end is fed into the USNR line that was installed last year. This will output around 130,000 sm³/shift/year.

The machine selection: Cambio debarker, 3D measurement, chipper, two quad band-saws where the first allows for curve sawing. Bent cants are put through the first quadruple band-saw again. All side boards are routed to the Catech high-performance edger. With logs of larger dimensions, up to 55 pieces per minute arrive at the edger.

Maximum curve sawing

"That we would opt for band-saws became obvious to us when we started thinking about the new building. In Estonia, the importance of large-dimension wood is growing so we want to utilize it with maximum yield and the highest possible flexibility," Ehrpais repeats. It was also his team who came up with the unusual idea of running two quadruple band-saws in series and complementing them with a high-performance edger. "With large-dimension logs, large amounts of parts accrue. The edger shouldn’t become a bottleneck in this process."

All from one – interface-free

USNR then made the offer that best fit Ehrpais' aims and ideas. It was also essential to him that all components come from one supplier.

"USNR is world market leader for band-saws," Hakan Westlund, USNR representative for the Baltic countries and Eastern Europe, proudly outlines the company's self-image.

"We already have a very neat roundwood sorting unit with 50 boxes. This means that at the Hekotek site, pre-sorting is performed," Ehrpais explains cutting preparation. After debarking (Cambio 800 – also a USNR product), the sawline follows.

Live optimization, optimal turning

The line's feed rate is at least 110 m/min. This is also the speed with which the 3D measurement at the sawmill entrance works. The true log contour is now established. Every log receives extra optimization on the short distance to the band-saw. "The secret of a perfect cut lies in the log turning," Westlund explains, "we guarantee a precision level of +/-5°."

The chipper reduces the log and hands it over to the first quad band-saw. Cutting is arranged in such a way that the servomotors have enough time to optimally adjust the units for curve sawing. In the worst case an occasional 1 m gap between two logs can occur.

Servo sheet guides

The band-saws are equipped with sheet guides. Depending on the log height, they can be servo-operated for adjustment so that every sheet is sufficiently supported. A special camera controls the teeth of the band-saw. If wear is detected, replacement is due. The cant is fed into the second band-saw or routed back into the cycle.

70 boards in peak, 55 in continuous operation

The two or four sideboards of the first band-saw are fed into the edger – a Catech 4000 TS-5. Viiratsi is the first place with a USNR top scanner with Bio-Luma2900 sensors. They have a scan rate of 2500 Hz and a resolution of 8 mm. The detected wood characteristics can be taken into account in two edger boxes. "70 parts were the all-time high so far, in continuous operation the Catech manages 55 boards," Ehrpais reports.

Five operators for two shifts and two lines

The systems are designed for minimal staff deployment. Only two operators per shift plus one stand-in make for an incredibly small operating team: five employees in a two-shift operation for the USNR and the parallel Veisto lines. The Catech edger for instance is operating completely unmanned.

Labor costs in Estonia are around half of what would usually be necessary in Central Europe. But: Wages have been climbing for years at a rate of 7% per year – so soon, they will have caught up. What bothers Ehrpais more, however, is that Estonia is suffering from a shortage of skilled workers. Furthermore, unskilled workers often are not enough anymore since jobs are becoming increasingly "computerized".

Around 50% of the Estonian timber harvest comes from reforested areas. This wood severely differs from cultivated wood from the autochthonous state forests. State forests consistently supply 4 million sm³/yr, private forests between 4 and 8 million sm³/yr, depending on the price situation.

More expensive roundwood than in Central Europe

In terms of roundwood prices, Estonia has caught up with Central Europe, or rather passed it by: €90/sm³ are the current price for spruce up to the sawmill, €90/sm³ for pine – around €15 to 20/sm³ more than previously customary. Considering sinking lumber prices on the global market, Ehrpais sketches the current year as follows: "It is hard. We have never worked so much and earned so little."

This year, Estonian sawmills are purchasing roundwood in Sweden. This means that commodity flows have changed direction. Viiratsi is "still" (Ehrpais) cutting 100% of Estonian roundwood.

Woodchips are being exported to Scandinavia. "The quality of woodchips has to be very good. Then, you also get the corresponding price," Ehrpais elaborates. For woodchips, it is the thickness that matters – and USNR has the right one. The Viiratsi plant is sorting three different grades.