Bending and Welding Trumpf Austria Relies on Hybrid Laser Welding from Fronius

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Trumpf Maschinen Austria from Pasching stands for innovative press brake and swing-folding systems. To further optimize sheet metal processing, Fronius welding technology is in demand there.

In recent years, Trumpf has experienced significant growth in the area of bending machines. Consequently, the product portfolio in this sector has been continuously expanded. The increased utilization also necessitated the purchase of heavy frames for bending machines. However, this extended production times, increased costs, and limited manufacturing flexibility. Welding was done manually by the supplier, requiring extensive rework. To avoid undesirable hardness increases in the steel after manual welding, the component also needed to undergo annealing. In this process, the steel is heated to up to 800 °C (1472 °F). During heating, the material reacts with the oxygen in the air, oxidizing on the surface and forming rust. Therefore, the components had to be sandblasted before painting," explains Thomas Reiter, Head of Production at Trumpf. However, with the new laser hybrid gantry welding system from Fronius, the company can now eliminate the energy-intensive and costly annealing process. Using the laser, the steel is now heated along the weld seam (depending on the material, to 150 °C to 180 °C, 302 °F to 356 °F), reducing the cooling rate after welding. Reiter comments: "This allows us to avoid hardening, cold cracks, and corrosion. Additionally, we are more independent and flexible thanks to in-house production." The energy savings correspond to the electricity needs of approximately 270 four-person households per year, assuming an average consumption of about 3,800 kilowatt-hours per household.

The Outstanding Features of Laser Hybrid Welding

According to Fronius, the laser hybrid welding process combines a laser beam directed at the weld seam with a GMAW process (gas metal arc welding) in a shared process zone. The highly focused laser beam is characterized by its high energy density and penetrates up to ten millimeters deep into the steel while welding the machine frames. Immediately after the laser processing, the MAG welding process (metal active gas welding) follows, filling the root and ensuring optimal flank bonding, as further explained by Fronius. The additional heat introduced gives the material time to degas and reduces porosity compared to pure laser welding. Depending on the sheet thickness, Trumpf applies up to 29 passes using the MAG process. The Fronius laser hybrid process offers Trumpf significant advantages over pure MAG welding. Reiter adds: "We save up to four tons of welding wire and valuable working hours per year because we can forego the labor-intensive beveling of sheet edges, especially with thinner sheets." This keeps the weld cross-sections small and requires less additional material. Trumpf can also increase productivity thanks to high welding speeds, which are a result of the stabilized arc created by the interplay of laser hybrid and MAG, as explained by Fronius. Additionally, the lower line energy reduces component distortion. Lastly, it must be noted that the welding process positively impacts the consumption of filler material, according to Reiter. The laser hybrid process also allows the weld seam to be positioned further inward. This enables closer proximity to the side parts during fillet welds, keeping the weld gap narrower.