The Bond & Beyond
As more shops embrace fiber laser welding technology, the new focus is on increasing automation
The advantages of laser welding technology are well known—it’s faster, more efficient and drastically reduces any need for post processing. But although it’s been widely adopted by OEMs, particularly in the automotive industry, there has been some hesitation from small and medium job shops. The price point has been a deterrent and despite the technology’s proven success in high-throughput production scenarios, laser welding’s performance in handling high-mix-low-volume process has been a big question.
Dan Belz, FLW product manager for Amada, says, “laser welding is really starting to pick up steam now. The price has come down on the equipment, making it an easier decision for companies. But another main driver for companies looking at this technology is they’re starting to be impacted by the shortage of skilled welders.”
The American Welding Society estimates there will be a shortage of almost 375,000 certified welders by 2024. “And that number is growing. For many companies, they can’t just have anyone welding some of their products. And there’s a shortage of qualified finishers. That’s an art–you can make a lot of scrap out of good welded parts if you don’t have a good finisher,” says Belz.
“It’s all about time that our customers can save with this technology,” says Masoud Harooni, product manager for TRUMPF’s laser welding group. “It’s not just OEMs using the laser welding technology. I can tell you that job shops use this technology almost at the same rate as OEMs. On thicker gauge material, laser welding gives you the capability to penetrate the part in overlap configurations, which traditionally would require a lot of preparation and post processing. And for visible welds on stainless steel that are used mostly in the food industry, for example, laser welding saves a lot of time on post processes such as grinding. The part that comes out of the laser welding cell is ready to be shipped to market.”
As adoption of this technology grows, suppliers are taking it to the next level and diving in to increase automation and create smarter, more flexible solutions.
Mind the gap
One key consideration when making the leap from manual or semi-automated welding to an automated laser system is the design of the parts. “It’s critical. Shops have been designing parts with large gaps because they know the welders are going to fill it with material. They’re going to put a pound of material on it and grind half a pound off,” says Belz. “We educate customers on how to tweak their designs—not change them, just modify the design.”
Andrew Newman, senior welding technologist for Fronius, agrees, “With laser welding systems you try not to have any gaps. The ideal joint configuration for laser is really close because your focus point and energy is so concentrated.”
Fronius’ LaserHybrid welding system is a three-in-one technology that combines MIG, laser and a combination option, designed for optimum gap-bridging. “Lasers give you very high power in a very focused area, which is good as it has a narrow penetration profile. But that process window gets much smaller if there are any gaps. With a laser alone you have almost no tolerance for gaps, so this hybrid system gives you a bit more of a process window where you’re creating a deeper penetration with the laser and using the MIG process to fill it in,” says Newman.
Once designers understand the gap tolerances and modify their part designs to accommodate it’s all about the fixturing. “We’ve come to realize in the past two years that fixturing is everything to make laser welding successful. We’ve started designing and building fixtures for our customers and have a few in the field that have held up nicely for more than a year,” Belz says.
He says it’s easier to fixture a well-made part, which will guarantee repeatable results and minimal post processing.
Dialing it in
Amada recently launched the FLW-3000 ENSIS, a second-generation system that now uses Amada’s ENSIS technology to increase its control over the laser beam. “We can go from a sharp point keyhole to a deeper penetration, to almost a donut shaped round for wider gaps,” says Belz. “And we have a second-generation wire feed system that increases our processing range dramatically.”
Compared to the first generation, which was 4,000 watts, Belz explains the FLW-3000 is using the same engine Amada uses for laser cutting, but it’s modified for welding with a different beam type. “This second generation is really a game changer. And even though it’s a 3,000 watt, we didn’t lose anything in the transition.”
TRUMPF is also focused on helping end users with design ideas, which will help customers save time and costs. It has introduced TeachLine as an option on its 5000 series, which introduces three reference points of a fixture or part that the robot uses during a production run. “This can be adjusted for every part or every 50 parts,” says Harooni. “It makes sure the original process is adjusted for movement of any part in the fixture. If the part shifts a couple of millimeters here or there, the robot can use the reference points and adjust the program based on the situation of the part.”
For high-mix-low-volume shops, processing multiple runs a day—run 50 of one part, 150 of another and 75 of a different part based on their orders—they’ll need to change the fixture for each run. TRUMPF recently launched its Zero Point Clamping System to help in these circumstances. “This feature ensures each time the fixture is installed on the working table to run parts, no program touch up would be required,” explains Harooni. “This feature is good for batch productions in job shops or OEMs as they have higher variation on parts and lower quantities. The changeover time will be less and there’s no touch up in the program required. If a customer’s part has a gap up to 0.04 of an inch they can use this technology to bridge that gap too,” says Harooni.
With Fronius’ hybrid system, the user is able to adjust the laser focal point up and down on an X, Y, and Z slide. One of the big advantages of this system, according to Newman, is it can be used on thicker plate steel to get deep penetration or thin plate for faster processing. “We can go up to over three meters per minute depending on the material type, size and joint configuration. If you’re working with thick plate, we can do a full penetration filler weld in 8 mm steel plates and still come through the other side of it. That’s a big benefit, especially if you don’t have access to both sides of the plate.”
In the last few years, Fronius has revamped its system, adding its new TPS/i welding platform. “That’s our new MIG platform. Now we can use some of the advanced wave forms that we have available. And we resigned the head to integrate a cross jet into the system that blows away any dust, fumes or spatter from the welding system. It helps keep the optics clean and the laser energy going through without being distorted or blocked in any way.”
Conveyor systems have also been integrated with welding cells to enhance automation. While the welding cell is running the part inside, the next part can be queued outside on the table by a human or robot. “The table will rotate and bring the outside part in and move the finished part on to the next cycle,” says Harooni.
With a finer focus on developing this technology to serve those with a more varied production flow, not to mention a lower price point for the speed, the quality and efficiency these machines deliver is finally making laser welding an attractive option for small and medium-sized fabricators. SMT