"Quality trumps all"

On October 15th, the time had come. One and a half years after signing the contract, LOC Holz produced its first cross-laminated timber panel in Arbing, all according to plan. However, that the first CLT factory in Upper Austria would also become one of the Homag Group‘s first large-scale glulam projects was not in the cards just yet. But first things first:

Together with sawyers Josef Lauss and Rudolf Ortner, Jan-Walter Cappelen from the Cappelen Group in Arbing built a cross-laminated timber plant called LOC Holz (Lauss, Ortner, Cappelen). It was clear from the beginning that the new plant was not to convince with quantity but rather with quality and tailormade solutions. "We come from medium-sized companies and now want to leverage our strengths also in the cross-laminated timber and modular construction sectors. Just like in the sawmill, we will offer products of the highest possible quality made from locally sourced raw materials at reasonable prices," Ortner sums up the basic idea and adds that in the course of project planning, all decisions were made in favor of the panel quality when in doubt – everything else was subordinated to this goal.

With this aspiration in mind, LOC Holz contacted many a machine supplier and finally settled on the Danish companies System TM and Kallesoe.

"System TM has a lot of experience in further processing such as the window industry, a sector revolving around high quality and high cycle rates while working with relatively small cross sections. This was exactly what we were looking for," Lauss remembers.

For cross-laminated timber, LOC Holz focuses exclusively on lamellas with only 125mm of width which is supposed to largely prevent cracking. The company‘s supreme product are knot-free rift surfaces. "The rift-sawn raw material from our frame sawmills provides perfect, crack-free surfaces at fair prices," Ortner emphasizes.

Maximum raw material yield

For these high qualities to remain economically viable, LOC Holz relies on a separate sorting line including a finger-jointing line for its production of cross layer lamellas from timbers with a length between 150 and 1000mm. "With this short-length finger-jointing line, we ensure optimum raw material yield for our customers," System TM CSO Per Jørgensen explains and adds that this concept is still relatively unknown in Central Europe. He mentions the CLT plant of the Egoin Wood Group in Spain as an example where System TM and Kallesoe have recently doubled the company‘s single-shift capacity to 50,000m/ yr.

The sorting line implemented by System TM also integrates a Rex planing mill as well as several scanner systems from Microtec. "We have successfully collaborated with both companies many times already, and we like to include their equipment right from the planning stage," Jørgensen informs.

Downstream of the sorting line, where the raw material is planed and graded and defects are cut out, the pieces are transported to one of the two infeed stations for longitudinal or cross layers, each equipped with several different infeed options.

"The option to feed in several stacks in different lamella grades increases the flexibility of the system – every single lamella is registered in the system and the master computer can pick out the suitable wood for the panels depending on the order," Jørgensen elaborates and adds: "With the separate cross-layer infeed, we see a significant performance increase at the finger-jointing line for long lamellas." For longitudinal-layer lamellas, System TM installed the newly developed Opti-Joint H-L high-performance finger-jointing line. According to the CSO, this horizontal plant not only impresses with large capacities but also with its high uptime and long service life: "With these characteristics, the plant is perfectly suited for the use in CLT plants."

Static side-face gluing

Downstream of the finger-jointing line, Kallesoe machinery takes over. After curing, the longitudinal-layer lamellas are passed on to another Rex planing mill and to the first high-frequency press. It presses three lamellas at a time to form a 37.5 cm wide surface which is then placed at the edges of the longitudinal layers. "This prevents individual lamellas from falling down in later production steps which significantly increases process reliability and therefore plant uptime," Kallesoe CEO Kristian Kallesøe informs. The finger-jointed cross-layer lamellas are passed through from the infeed station to a lamella planer to a high-frequency press which combines the pieces to form full single-layer panels.

The glue used here – just like in the longitudinal-layer press and later on the surface – is a load-bearing MUF adhesive from the Swedish manufacturer Dynea. "Given our ambition to produce panels of the highest possible quality, implementing loadbearing narrow-face gluing was inevitable. To this end, as in a lot of other areas, a MUF adhesive offers great advantages," Ortner explains. 

Massive output boost

After narrow-face gluing, the longitudinal and cross layers are combined in the lay-up unit, coming from a buffer. Here, Oest is responsible for the application of a two-component adhesive before the press cake is transported to the heart of the line, a 400 kW high-frequency press. "It is the most powerful press that we have built to date. Compared to the previous model, we were able to increase the output by 75%," Kallesøe is proud to report. The press is designed for panels between 2.5 and 3.5m of width and up to 18m of length.

For the LOC team, however, the flexibility of the press was much more important than the maximum length: "With the high-frequency press, the production of smaller panels without any capacity loss is possible. This allows us to make optimum use of the raw material and serve our customers in the best possible way," Lauss explains. After the press, the raw panels are conveyed through a planer on to a PBA panel processing machine from Hundegger.

When asked about the challenges that come with the high-frequency technology, LOC Holz is not worried. "Of course, we are aware that with the HF presses, we have chosen the more complex technology. However, our aspiration has always been to take the best route and never the easiest one. In addition, we are in the best hands with the market leader in this field," Ortner emphasizes and adds that they are currently installing a photovoltaic system for an energy self-sufficient production in the future.

Joining forces

Unlike a year and a half ago, Kallesoe and System TM are now part of the Construction Element Solutions (CES) division of the Homag Group. A fact, though, that had little influence on the project in Arbing.

"We are still autonomous companies and have already been collaborating successfully with Kallesoe before the takeover," Jørgensen emphasizes, and Kallesøe adds: "And what is more, as part of the Homag Group we now have an even broader base and are much closer to the customer." While Homag is primarily responsible for the initial contact and comprehensive services with its worldwide subsidies, Kallesoe and System TM are handling project planning, detailed design and implementation.

"Every customer approaches us with their individual and very different ideas and expectations. Together, we then develop a tailormade solution using our numerous tried-and-tested modular building blocks," the men agree. Apart from LOC Holz, CES is currently realizing two other turnkey CLT projects: one for the Egoin Wood Group in Spain and another one for Timberlink in Australia. And additionally, numerous glulam projects are in the pipeline.