According to Markus Thier, having as few interfaces as possible, honest communication and machine suppliers who approach problems openly and in a solution-oriented way are essential prerequisites for a project of this dimension. The operations manager of Mayr-Melnhof Holz’s new CLT plant in Leoben already knew Ledinek from several successful investment projects at the Gaishorn processing site and was therefore very much familiar with the plant manufacturer’s strengths and experience. “Of course, we were also in contact with other machine manufacturers but, in the end, Ledinek offered us the most suitable complete package,” Thier says, explaining the decision.
Ledinek employs solution-oriented staff who pursued the two central goals right from the start: achieving the agreed performance figures and successfully putting the machines into operation.
Meticulous planning
The main objective of Mayr-Melnhof Holz was as clear as it was challenging: At the former Novopan site, adjacent to the sawmill and headquarters of the group in Leoben, one of the world’s biggest CLT plants was to be built, with a production area of over 3 ha. In the future, up to 140,000 m³ of high-quality cross-laminated timber are to be produced in the plant every year – and with the highest possible degree of automation. The €175 million investment also includes a post-sorting and planing line for lumber with a capacity of 700,000 m³ a year, including a fully automated high-bay warehouse with space for up to 28,000 m³ (in the first phase of expansion).
Drawing on the experience gained from the delivery of over 30 cross-laminated timber presses and the installation of 22 complete systems worldwide, Ledinek had all the essential machine and system components in its repertoire for the CLT plant in Leoben. “Due to the size of the project, its complexity and the requirements for performance, we had to adapt numerous detailed solutions and newly develop individual sections, such as the direct connection to the high-bay warehouse,” Ledinek’s Bernhard Fandl tells us, adding that his company approached the project with a lot of respect and was even more meticulous than usual when it came to planning. When in doubt, Mayr-Melnhof Holz always chose the higher-performance option.
With the launch of the CLT line, we have achieved our biggest common goal to date. This was made possible by the customer’s great vision, which our two teams made a reality thanks to perfect collaboration.
Sophisticated detailed solutions
When you look at the investment as a whole, Ledinek’s plant solution starts in the planing mill. There, a high-performance Stratoplan 6VR-S1000 planer, including a Powerfeed infeed unit with a speed of up to 1,000 m/min, ensures the necessary throughput.
In the cross-laminated timber plant, Ledinek’s mechanization takes over the lumber packages from the high-bay warehouse. “From this point on, the X-Lam Manager, our production control system, manages the entire production process right up to the finished raw panels,” Fandl says, explaining the virtual part. What is physically visible, on the other hand, is a shuttle which automatically transports the packages to one of the two-level buffer locations or one of the eight destacking areas.
The shuttle automatically transports the packages to one of the layer destacking stations where the lengths of the laminations are determined layer by layer before the individual laminations are transported on longitudinally. In front of the X-Cut S400 cross-cut saw and the subsequent finger-jointing lines, Ledinek implemented a large buffer space. According to Fandl, this and other generously designed intermediate storage areas are necessary to ensure a smooth process despite the complete automation.
Powerful individual machines
Two high-performance Kontizink 2500 finger-jointing lines with a throughput of up to 2,500 m/h achieve the necessary performance. Nevertheless, space has already been reserved for a third line of the same type for the next phase of expansion. “In glued timber projects, it is often the finger-jointing line that does not deliver the desired performance and ends up slowing down the entire production process. Since two identical lines are already successfully in operation at our glulam plant in Gaishorn, we knew in advance that this area would work,” Their explains.
From the finger-jointing line, the laminations are transported to an extremely spacious multi-level storage system, where the finger-jointed elements are stored in layers. In this area, Ledinek optimized its lift systems to make sure that elements can be stored and taken out of the storage area as quickly as possible. In addition, an automatic removal system for test pieces and waste was implemented. The latter is removed via a vibrating chute.
All other laminations leave the curing storage area and pass through one of the two Superplan 4V-S350 planers and are handled by a turning device before they enter one of the two Z-Press lines. The presses use hot-melt and white glue to press the wood into single-layer panels, which are then brought to another spacious multi-level storage system.
Only after they leave the storage area for single-layer panels do the longitudinal and crosswise layers go their separate ways. The longitudinal layers are positioned directly in front of the laying portal, while the crosswise layers are separated and placed in another multi-level storage system.
It doesn’t get any faster
Ledinek and Mayr-Melnhof Holz also put a lot of development work into the panel laying system. It consists of a moving table that moves under a stationary Oest adhesive application system and receives a longitudinal layer on one side and a crosswise layer on the other. “This eliminates empty runs and the laying portal can hold the next layer in position just a few centimeters above the press cake,” Fandl explains and adds: “You can’t lay cross-laminated timber any faster.”
The final step in the production of the raw panels is carried out by two third-generation X-Press presses for elements with a maximum length of 16 m and widths of up to 3.5 m. Ledinek puts the specific pressing pressure at a maximum of 0.8 N/mm² when the press is filled to its width.
Entire mechanization
Via a turning station and on conveyors, the raw panels are transported to the next production hall, where Ledinek implemented two stations for cosmetic corrections with a turning device in between, the entire mechanization between the grinding and joinery machines as well as parts of an additional buffer storage area for panels in front of the joinery area. “Our mechanization includes everything from taking over the raw laminations to the loading hall behind the joinery machines,” Fandl says, summarizing the extent of the project.
Well-deserved praise
Despite difficulties in delivering individual components due to the pandemic, Ledinek and Mayr-Melnhof Holz implemented the giant project in Leoben without any significant delays. In April 2023, only two years after the groundbreaking ceremony, the first panel was pressed. The approval followed in May and at the moment, the plant is in the middle of undergoing the agreed performance tests.
“Since both of our teams were always straightforward and open, and everyone involved was solution-oriented, we were always able to react to small problems in a timely manner before they became bigger,” project manager Manuel Staber says about one of the crucial factors of success. “Ledinek is a long-standing supplier and partner of Mayr-Melnhof Holz. We have successfully implemented many joint projects in the past. Ledinek’s product range and ambition to continuously further develop its solutions, the improvement of the machines, combined with the experience from many large-scale projects, were particularly important for us, as was the geographical proximity of Ledinek to Leoben. The company employs solution-oriented staff who pursued the two central goals right from the start: achieving the agreed performance figures and successfully putting the machines into operation,” Mayr-Melnhof Holz’s CEO Richard Stralz adds.
Ledinek’s managing director Gregor Ledinek also praises his project partner: “Mayr-Melnhof Holz has been one of our biggest and most loyal partners for more than 30 years. With the launch of the CLT line, we have achieved our most ambitious common goal to date. This was made possible by the customer’s great vision, which our two teams made a reality thanks to perfect collaboration.”
