MANUFACTURE OF CLT PANELS

The Sokol Timber Processing Plant (TM Sokol) has a guaranteed supply of timber (round timber / sawlog). Since 2011, the company has been leasing forest plots with a total area of 159,681.8 hectares with an estimated logging volume area of 364,600 cubic metres. Logging is performed by a special purpose independent business unit operating out of Vologda.

SOKOL saws timber on a special timber sawing line that uses a HewSaw R 250SE timber-sawing machine manufactured in Finland. The product of this stage of the process is sawn timber.

Sawn timber is dried in BOLLMANN (Germany), MULBOK (Italy), Jartek (Finland), Baschild (Italy) Vаlutek (Finland) to reduce the moisture content to 12±2%.

• Once dried, the sawn timber is moved to the CLT shop.
• Here, it is aged for at least 2 days before being fed into the Ledinek optimisation line.
• The temperature and relative humidity in the shop are continuously maintained and recorded by a thermohydrograph. The timber moisture content during the production of CLT must not exceed 14%. The moisture content of the timber (the minimal temperature of the timber must be 15°C) is measured automatically with a moisture meter. Timber with moisture content outside the required range is automatically rejected.
• The sawn timber for the production of CLT is sorted in accordance with the European standard EN 14081 and the quality requirements for internal and external surfaces.

• Workpieces get calibrated and sorted by strength and quality before being fed into the Kontizink LH-S80 Ledinek Slovenia splicing line. The tenons required to connect the lamellas are cut parallel to the width of the workpiece on a tenon-cutting machine, first on one side of the workpieces, then on the other.
• Glue is applied to the surface of the cut tenon along the entire length (combs are used to apply the glue separately on both sides of the workpieces being spliced).
• The workpieces being spliced are pressed together under a pressure of up to 11 N/mm2.
• The butt-ends of the lamellas are cut to the required length, with the lamellas then being stacked on the stacking table.
• An adhesive system from the global leader Akzo Nobel is used to laminate the workpieces together.

• Once laminated along their length, the lamellas are moved from the stacking tables to the planer and to the Ledinek Z presses (to make longitudinal and cross-sectional panels).
• Molten synthetic glue is applied to the butt-end of the lamella in a non-contact manner.
• The panels (layers) of the slabs are pressed to the required length and thickness.
• The slabs with longitudinally positioned lamellas are then moved to the stacked storage area in the slab-pressing zone. Slabs with transversely positioned lamellas are stacked on the transporter after the Z 3.5 press.

• Each panel must be comprised of at least three layers. The layers of multi-layer panels must be positioned orthogonally. Panels are pressed in a Ledinek X press.
• The dual-gantry vacuum unit accepts long and short layers from pre-prepared stations and transfers them to the table for forming a panel.
• After each row is stacked, the table is moved to the adhesive application station, where the Loctite HB S109 PURBOND one-component polyurethane adhesive is applied.
• Once the glue has solidified in the press, the air is let out of the clamping beams, allowing them to rise. The table with the panel moves out of the press.
• The temperature and relative ambient humidity in the shop are maintained at a constant, the pressure and time in the press, as well as the thickness of the laminated seam, are also monitored.

• The finished panels are polished on a COMBI 2.6/360 2-head polishing machine manufactured by IMEAS (Italy).
• Every panel is visually inspected by staff and repaired if necessary. The strength of the product is not reduced; only external defects are eliminated.

A CND SCM AREA XL processing centre (manufactured in Italy), featuring a frame comprising a stationary table and a mobile portal with a processing unit installed on it, processes the panels' perimeters and makes any necessary groves, holes, doorways and window portals in them so the panels can be used as home construction components.

• Quality assurance is an ongoing process that ensures the tenons are laminated together properly; the laminated seams are of the target quality level and all equipment used in the production of the CLT panels functions as intended.
• The quality assurance system is regularly checked for effectiveness and adequacy.
• All product test results are logged by the laboratory.