The hybrid way

© Photo | JackJelly / iStockphoto

Seiwald is a jobshop and offers laser hybrid welding. Deputy general manager Dieter Achleitner explains why the move paid off.

The hybrid process comes from shipbuilding. Here we are at the foot of the Alps. What do you weld?

It’s true enough that we don’t have any shipyards among our clientele. We do a lot of work for the vehicle construction sector. But there is also one thoroughly Alpine application: snow cannons.

There is more

The companies

The familiy run company in Tyrol, Austria, is specialized in metal processing by laser cutting, laser welding and water cutting. It supplies industry, building industry and special vehicle producers.

The Austria-based company has more than 3, 200 employees.They creates new technologies and solutions for monitoring and controlling energy. For battery charging systems, welding technology and solar electronics.

The welding technology

Hybrid Laser Welding combines laser welding and arc welding. In principle, using the two methods together unites their strengths while cancelling out their respective weaknesses.

The arc acts on the surface and provides a broader seam, which, in turn, bridges gaps. It also transports additional material into the melt. These characteristics give the welder a direct influence on metallurgical properties and adhesion to the seam flank.
Laser welding ensures a deep weld and high process speed while lowering thermal entry. It also reduces thermal warping to a level below that attainable with arc welding alone.

Fronius delievered the hybrid laser welding technology to Seiwald.

The basis

TruLaser-Robot-5020

The TruLaser Robot 5020 is a highly integrated system. It is a building block in the TRUMPF LaserNetwork for the processing of complex seam geometries. It consists of commercially available, standardized components.

The beam source

The TruDisk disk laser combines the advantages of a solid-state laser with those of a diode laser. The diode laser, as the pump source, provides the excitation energy and ensures high efficiency. The disk, as a solid-state laser, ensures high beam quality.

Snow cannons?

The mouth is actually an aluminum ring incorporating water nozzles. Channels inside the ring supply water to the nozzles. The manufacturer first takes a solid component and then turns the channels in the form of open grooves. We close them off by welding them shut from above. The seams have to master intense variations in stress and withstand test pressures of up to 120 bar.

Was this design developed for hybrid welding?

Muendungsringe-der-Schneekanone-aus-Aluminium

Aluminum rings for snow cannons.

No, but it is a very nice illustration of what makes hybrid welding interesting for us. By rights, automatic welding of the seams should work wonderfully well. But their tolerances, the qualities of aluminum as a material, and the weld depth make normal laser welding impossible. So instead, the parts were always welded by conventional means. Our hybrid laser welding robot, by contrast, has absolutely no trouble dealing with the material, tolerances, and weld depth, and it completes the six continuous seams in a fraction of the time.

Outside of shipbuilding, hybrid laser welding is normally associated with the high output and long production runs typical of automotive manufacturing. That doesn’t really fit the profile of snow cannons.

That’s right — we don’t have these huge lots of two or three hundred thousand units. But getting large contracts wasn’t our aim either. That would mean fundamentally changing our business, handling a few big orders for a few big customers. What we were actually looking to do was to procure an advantage for our many customers — big and small — by installing a new technology for their short and medium-scale batches.

Dieter-Achleitner-in front-of-Fronius-and-TRUMPF-designed-laser-hybrid-welding-machine-with-TruLaser-Robot-and-TruDisk

Deputy general manager Dieter Achleitner standing in front of the machine, designed in collaboration with Fronius and TRUMPF. Behind him, across a travel path of 7,000 millimeters, is the beam source, a TruDisk 4002.

How did your specific requirements as a job shop affect the configuration of the machine?

When we started planning the machine together with Fronius, the main condition was great flexibility. That’s why it masters three different processes: hybrid laser welding, the pure laser process, and CMT — cold metal transfer — welding, an arc welding process developed by Fronius, one that is very quiet and can be controlled precisely. The machine is based on a TRUMPF TruLaser Robot 5020 with a Tru Disk 4002 solid-state laser generating four kilowatts of power. To be able to weld very long components such as crane jibs and truck trailers, the machine has a longitudinal axis of seven meters. For more modestly sized components, there is a turn-and-tilt table, so that we can reach areas that are hard to get at. And we have installed a shuttle table to handle large manufacturing runs.

The rotary shuttle table gives a glimps into the processing cell.

The rotary shuttle table gives a glimps into the processing cell. Click the gallery to see how it looks behind.

What do you consider to be long production runs?

Orders for a few thousand parts per batch are not infrequent. This is where the machine achieves its full potential. But recently we’ve been getting more and more enquiries about critical situations, where the weld’s loading capacity and quality play a decisive role. In such cases, we are often talking about a few workpieces or even just one. The added value for our customers is that they have quality control and detailed documentation of the welding.

Pure laser welding already offers these advantages. What made you take the further step of acquiring hybrid laser welding capability?

Our machine gives us the option of working with a pure laser process whenever we want. But the laser method on its own is too narrow for us.

Narrow? Most people would say it has a broad range of applications. Isn’t that what makes it so popular among job shops?

Again, that’s a matter of perspective. Of course laser welding offers a great number of possibilities within a specific field. But we often have to deal with components that are thick, with deep welds. On top of that, more and more ultra-high-strength steels are coming into our shop, and these often pose problems for the pure laser.

Why is that?

One reason is that the tolerances after hardening are often too small for the pure laser process. And yet re-working is not an option. With the hybrid process, on the other hand, there is no need for finishing. It is also a question of heat input. A pure laser process has extremely short cooling times, which can lead to imperfections. The pure arc welding process injects too much heat and softens the material. By contrast, the hybrid process gives us the option of precisely metering the heat input by adjusting the laser and MIG/MAG torch parameters. That lets us weld with minimum structural change to the material. And the filler material in the welding wire allows us to further influence the properties of the weld — its toughness for example.

With your machine, you effectively have no competitors. Have you noticed any effects?

It’s true that there are virtually no other job shops offering hybrid welding. On the other hand, there are still very few companies specifically looking for this service.

laserhybrid-welding-fronius

Get to know more about robot-guided laser hybrid welding in this Fronius video.

Putting it bluntly, does that mean you get a lot of orders not because of but in spite of the hybrid laser welding machine?

I wouldn’t put it in quite those terms … The thing is, our market works like this: Most components that are sent out to subcontractors can be processed effectively using conventional methods. Conse-quently, when we suggest making a part on the hybrid laser welding machine, we often have to justify the benefit to the customer. On paper, the process often costs them more for small- and medium-sized series because, for one thing, we need more precise clamping mechanisms.

What is it that convinces your customers in the end?

Some welcome the fact that they can continue to design for conventional processes while also getting their workpieces back much faster and at better quality than before. Others discover that there can also be design advantages for them when they go the hybrid laser welding route. And all our customers value the reproducible quality of the welds and reliable process documentation — in other words, all the advantages offered by this high level of automation.

Contact:
Seiwald Blechform
Dieter Achleitner
Phone +43 664 5430856
email: d.achleitner@seiwald-blechform.at

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