In order to secure the lumber supply for his CLT production, Leonhard Unterrainer developed a completely new sawmill concept. The roof of the new sawmill hall is made of specially produced radius timber © Johannes Puch
For around 20 years, Holzbau Unterrainer, Ainet, has been one of the few timber construction companies to produce cross-laminated timber in house. The resourceful entrepreneur has been working with large-format, curved CLT made of spruce and larch wood for just as long. In 2010, the company invested in a CLT press with a capacity of 20,000 m³ a year. The elements, which have maximum dimensions of 13.5 by 2.95 m, are manufactured in the same press as standard CLT components. The curvature is achieved with special, individually controllable pressure elements. “The market is too small for the timber industry and the effort too big, and this creates a successful niche for us,” Unterrainer says, describing his very comfortable standing on the market for curved CLT.
The joining of the elements, whether they are curved or straight, is done with a Techno Wall mobile bridge joinery machine from Italian manufacturer Essetre. Installed in 2019, the machine is reducing the workload for several employees who can now be put to good use elsewhere.
Independent supply
In addition to classic, straight CLT, Holzbau Unterrainer also produces curved and three-dimensional free-form elements © Unterrainer
Unterrainer took lumber supply for the CLT production into his own hands by investing in his own sawmill. More precisely, the entrepreneur developed a completely new concept for the sawing of log wood together with a Tyrolean manufacturer of special machines. Since his vision became a reality, Unterrainer has been sawing all of the raw wood for his CLT factory on just 400 m² of floor space, with one employee and no log yard.
Holzbau Unterrainer accepts unsorted logs with a top diameter of 25 to 80 cm and transports them to the sawmill hall via an infeed station. There, the logs are debarked, cut to length and measured. Once the logs have been fixed along their front sides and turned until they are in the ideal position, they are profiled, sawed and rip-cut in just one pass using two milling units, a horizontal band saw and a circular saw.
Unterrainer puts the log yield at 70 to 80%. Up to 65% of the log wood is processed into main lumber grades. In the last step, the boards are removed using a vacuum lifter and then scanned and packaged.
In order to be able to dry the lumber on site, Unterrainer ordered two condensation drying kilns from Italian drying systems manufacturer Incomac. This way, the company can dry 12,000 m³ of lumber a year in-house.
