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Timber construction: Complete machining with speed advantage
Timber construction: Complete machining with speed advantage
Industrial Hydraulics

Timber construction: Complete machining with speed advantage

Carpentry and timber construction companies are booming all over the world, because wood as a sustainable material for architecture is very much in vogue. With the "PowerCut" MC-15 machine centre, Krüsi Maschinenbau AG offers a new throughfeed machine that completely processes wooden components from all six sides in one clamping. The result: up to 15 percent faster processing and lower costs compared to previous joinery centres.

Financed public buildings in Franc

The curved roof structure of the Centre Pompidou in Metz, resting on four supports, was made of laminated spruce wood and is coated with a waterproof, white membrane skin based on glass fibre and Teflon. (Image: Holzbau Amann GmbH in Weilheim, Germany)

From 2022, all public buildings financed by the French state in France will have to be made of 50 percent wood. This makes France a pioneer for the renewable raw material. This makes it all the more important to process wooden components for architecture as economically as possible. This is where Krüsi Maschinenbau AG from Schönengrund in the canton of Appenzell Ausserrhoden comes into play. The company has been a globally active supplier of high-quality woodworking equipment for six decades. "We have sold more than 3,100 machines in 38 countries since the 1960s," says Urs Iseli, Managing Director of Krüsi Maschinenbau AG, proudly. "Many of them are used continuously in three-shift operation and sometimes under extreme climatic conditions." With the "PowerCut" MC-15 machine centre, the company is now setting a new standard for efficient woodworking.

6-sided machining in one set-up

As a throughfeed machine, the MC-15 saws, mills and drills wooden components of any length from all six sides in one clamping. As standard, the loading and unloading stations are designed for components up to 8,000 mm long. However, this is individually adapted to customer requirements. The passage accommodates components up to 1,300 mm wide and up to 300 mm high.

For machining, the system can be equipped with up to six freely swivelling and rotating 5-axis sawing and milling units. The 1, 2 or four spindles of the patented milling units hold enough tools so that no tool changes are necessary during production. The machine centre controls the axes simultaneously using multi-channel technology. For example, while the saw is producing a dovetail joint, a milling unit is already moving into position for the next machining step. In this way, the machine reduces the chip-to-chip times.

Hydraulics supplied ready for installation

All units are mounted on a crossbeam. This has a hydraulic counterbalance in the Z-axis. "With this, we only move mass, but no weight," emphasises Urs Iseli: "I can move the weight of up to three tonnes with my little finger." When it comes to hydraulics, Krüsi has been working with Bosch Rexroth for decades. "We designed the compact power unit, accumulator, the control block with five interlinked valves and the hydraulic cylinders together with the specialists from Rexroth, and they are delivered to the assembly shop ready for installation," emphasises the business manager, who has been with the company for 35 years.

The Z-axis is positioned via toothed racks and centrally lubricated roller rail guides from Rexroth by a gantry drive with two servo drives. Thanks to the weight compensation, Krüsi can design the electric drives much smaller and still achieve high dynamics. "Our customers reduce their machining times per workpiece by up to 15 per cent with the MC-15," calculates the business manager. The MC-15 combines the speed advantage with a machining accuracy in the range of tenths of a millimetre.

Automatically produce individual components

While NC machines in metal processing often produce large quantities of identical components, wood constructions are about individual components. For the carpenter, there is no remote timber construction without a counter arrow. "Our machines are equipped with the BTL interface," says Urs Iseli, describing the simple operation of the MC-15. Architects create the timber list and geometry data in BTL format in their planning files. The CAM system generates the ISO code for each component from this and the operators only define the machining strategy. While one process is still running, the control system is already checking the next machining operation to make sure there are no collisions. When the finished part is discharged to the left, the machine already loads the next blank on the right side in parallel with machining time and machining starts without interruption.

Automatically produce individual components

Architects Shigeru Ban and Jean de Gastines have collaborated on the Centre Pompidou in Metz to create a magnificent wooden structure that is so light it seems to float. (Image: Holzbau Amann GmbH in Weilheim, Germany)

Life expectancy: 30 - 40 years

The Appenzell-based company pays special attention to the quality and longevity of all its machines. "That's why we also value reliable technology partners like Bosch Rexroth, who also provide spare parts quickly worldwide."

Demand for the new "PowerCut" MC-15 is high among carpentry firms as well as large timber construction companies. More and more architects are taking advantage of the degrees of freedom offered by timber construction to create sometimes spectacular designs: whether in the new Swatch headquarters in Biel, in the Centre-Pompidou in Metz or in the more than 20-year-old EXPO timber roof at the Hanover Trade Fair, custom-made timber components have been created on Krüsi machines. But also utility buildings such as the highest roller coaster in the Korean Everland Theme Park with several tens of thousands of individually machined wooden beams show how durable and reliable wood is as a material for construction.

Marco Schmitt

Marco Schmitt

Is a sales engineer at Bosch Rexroth Schweiz AG in Buttikon in the industrial hydraulics sales department. He has many years of experience in the design, sale and commissioning of hydraulic systems. Among others, Marco Schmitt also supports the company Krüsi Maschinenbau AG in Schönengrund.