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Jul 09, 2023

Leading with Light

Modern medicine, telecommunications, consumer electronics, building construction and data storage. These are just a few of the technologies that would be far less advanced, if not impossible, were it

Modern medicine, telecommunications, consumer electronics, building construction and data storage. These are just a few of the technologies that would be far less advanced, if not impossible, were it not for the work of laser pioneers (see sidebar on p. 46) such as Theodore Maiman, Charles Townes, Arthur Schawlow and countless others.

But nowhere has their work had a more profound effect than on the production floor, where an increasing number of manufacturers use lasers to slice through metal, join, mark and inspect parts, set machinery and, above all, keep workers safe. This is especially true when pairing lasers with automation (although there are many definitions of this).

The most powerful lasers—those used for cutting—have long been accompanied by automated material handling systems. They come in the form of simple load/unload stations or, in some cases, multi-rack towers able to store prodigious numbers of sheets and load them individually into a laser cutter for processing. In either case, the machine typically delivers the cut sheets to a nearby pallet or table, where an operator separates and sorts the parts.

Brendon DiVincenzo, head of solutions for the Americas market at Bystronic Inc., Hoffman Estates, Illinois, notes that the dynamics of this fairly standardized approach are changing. “For many years now, cutting has been the bottleneck, so it didn’t matter so much what happened on either end of the machine,” he says. “But that equation’s starting to change. Fiber lasers are getting so fast that customers have begun demanding more effective load and unload capabilities to keep up. These include automated sorting systems, together with larger, faster and more flexible towers.”

One example is Bystronic’s recent introduction of a 30-kW laser, which DiVincenzo says, “can handle 1.25-in.- (31.75-mm) thick steel without much fuss, but can cut nearly twice that thickness in certain applications.”

As noted, tower systems are also becoming more capable, but perhaps the biggest change is a growing acceptance of automated sorting.

“Do the math on the higher cutting speeds and what that means in weight throughput, DiVincenzo notes, “and you’ll quickly realize that, even if you can find two or three people to stand there all day, it’s unlikely they’ll be able to keep up.”

Michael Bloss, the west coast laser product manager for Amada America Inc., Buena Park, Calif., notes that there’s much more to laser productivity than wattage alone. “I worked with a customer who was cutting some hardened 1-inch-thick (25.4 mm) plate on a 12-kW machine,” he says. “The speed was okay but the edge quality wasn’t all that great, so we tried it on our VENTIS, which is a single-module, 6-kW fiber laser. The cut was pristine.”

There’s clearly a place for newer, high-wattage lasers, though Bloss suggests that comparing one to Amada’s flagship VENTIS line is akin to pitting a finely tuned racecar against a diesel-powered pickup truck—the latter has plenty of muscle, but might not deliver the desired quality and precision.

Amada and the other companies interviewed for this article offer robust material handling systems, all of which deserve a serious look by any shop wishing to increase throughput. But, as Bloss points out, automating various aspects of the cutting process also merits evaluation.

“We have numerous monitoring and control functions available on some of our models, such as the i-CAS, which is a camera that captures an image of a sheet and allows the operator to drag and drop part files onto unused areas,” Bloss says.

V-Monitor is a camera that continuously records the cutting area and flags events that might trigger an alarm. Then there’s Amada’s i-Nozzle Checker that automatically keeps the beam centered and focused in the cut, the i-Optic sensor that alerts the operator to lens contamination (and potential damage), and an advanced piercing feature that senses when the beam breaks through so it can commence cutting, eliminating lost time. “Amada is always adding features like these that help to make the process faster and more predictable,” Bloss says.

Mazak Optonics Corp. of Elgin, Illinois, makes similar claims. Automation Specialist Jacob Fogarty says the company’s OPTIPLEX 3015 NEO boasts camera-assisted part nesting and nozzle centering, and, similar to other builders, has developed proprietary beam-shaping technology to provide optimal cutting in different materials and thicknesses.

“In addition, we’ve introduced several control functions that make it easier for the operator to ensure they’re achieving optimal cutting performance,” Fogarty says. “But we also have a wide range of automation solutions and automated part sorting systems like our new Smart Cell, which can independently pull parts from a nest and then place them on a conveyor or stack them on a pallet for secondary processing.”

The push toward laser cutting that relies less on skilled operators and more on automation and advanced control systems is not unique to Mazak or Amada, nor is it limited to 2D-laser cutting—automated laser technology is just as important to 3D cutting, welding and marking.

From its Laser Application Center in Plymouth, Mich., Trumpf Inc. is making similar advances, particularly in the automotive sector. Jack Pennuto, director of sales and applications for laser technology, explains that much of this effort is in response to the industry’s increased use of boron steels, which greatly increases the material’s strength.

“Over the past decade or so, automakers have adopted more press-hardened or hot-formed steels in their structural components,” he says. “The problem is (that) stamping holes in these materials is quite challenging, so many manufacturers have turned to laser cutting instead.”

Even without the current workforce woes, automotive and automation have long been synonymous. Carmakers are building on that relationship by investing in laser cutting with robotic loading and unloading, a need that Trumpf is ready to meet. “One example is a component they refer to as a shell,” explains Pennuto. “It’s a rough-formed part that’s placed on a rack for presentation to a 3D-laser cutter. A robot places it on a fixture, and this is then indexed into the machine, which cuts the holes and trims everything to size. From here, the robot moves it to a different rack for welding and other downstream processing. Implementing robotics creates a process that can run lights out without human intervention.”

This more flexible 3D processing is another area where fiber lasers shine. “Automotive manufacturers are producing cars with fewer, but more complex, parts. Door pillars are a good example of this,” says Travis Stempky, Trumpf’s high-power laser application supervisor. “Because welding with a fiber laser is a non-contact process, you can be farther away from the part, making it easier to reach areas a traditional welder can’t. Using this flexible laser tool gives manufacturers more freedom to create designs that achieve excellent part fit-up and reduce costs.”

Fiber Laser Welding (FLW) Product Manager Dan Belz of Amada is seeing similar calls for laser welding systems, many of them for high-volume applications. He shares another example—albeit from an unexpected direction—one that illustrates the flexibility of today’s laser technology: spot welding.

“Last year, we developed a special machine for a customer who wanted to join very high volumes of HVAC components,” he says. “At the time, they were drilling and tapping holes and then attaching a small hook; as you can imagine, it was very labor intensive. So we took one of our existing laser welders, added a turntable, and delivered a fully automated cell.” Laughing, he adds: “Spot welding is a straightforward process, so I was a little skeptical about using a fiber laser, but it was a huge success. There’s no dimpling, no burning or scorching, the joint is much stronger, and the customer is saving half a million dollars a year on the material alone.”

A fair percentage of laser welding is done without filler metal, meaning the laser’s collimated light is sufficient to melt and join the two workpieces. But as Lincoln Electric Co.’s Elliott Ash points out, using filler wire or rod (as with traditional metal inert gas and tungsten inert gas processes) provides the opportunity to add alloying elements to the weld joint, adding strength. “It also means you can perform cladding operations, where you might add stainless steel or a hard-facing metal like (Kennametal Inc.’s) Stellite to a part surface to increase wear resistance.”

Ash is a welding engineer for the Cleveland, Ohio-based welding provider. He describes two laser-based processes of particular interest to companies in the electric vehicle segment, that use them to join battery trays and terminals. However, he’s quick to point out that each is equally suitable for non-automotive applications. Both are also “automated-only” welding processes, so don’t plan on sticking one of these systems in your garage for hobby work.

“The first of these is hybrid laser-arc welding, or HLAW,” he says. “Here, you create a keyhole with the laser, keeping the weld zone molten so that the MIG process following it can fill in the joint. This technology gives excellent penetration at high travel speeds and high deposition rates; the challenge is keeping that molten keyhole active and stable, so you have more to deal with than a straight MIG process. Precision power laser (PPL) simplifies much of that.”

PPL is an arcless, “hot-wire” process. It’s also proprietary to Lincoln Electric. Here, an advanced welding power supply heats the filler metal as it enters the weld puddle created by the laser. There’s minimal distortion and no need to machine large bevels in preparation for the weld—a slight chamfer is all that’s required, reducing costs. It’s also a “colder” process, therefore it’s ideal for thin-gage sheet metals, although as Ash explained, it’s also suitable for heavy plate.

“We have applications where we’re joining seven-inch-thick (178 mm) material and doing so much more quickly than we could with a conventional approach,” he says. “But where PPL really excels is on the thin stuff—in some cases, we can achieve weld speeds of three meters per minute. It’s quite fast.”

Dave Cotton is the business development manager of flat sheet laser (LS/LC) products for BLM Group USA in Novi, Mich. He and North American Laser Product Manager Robert Adelman can’t speak to welding, but both have extensive experience with laser cutting of sheet and tube stock, as well as the automation of each.

Cotton reiterated what Brendon DiVincenzo of Bystronic alluded to earlier: The bottlenecks that laser cutters have long presented and today’s higher-power, more efficient lasers are making it necessary to automate downstream handling processes. “The industry as a whole is busy evaluating how to develop new systems in response to more capable lasers, but is also taking some of the current or past automation capabilities and enhancing them. Because of this and the current labor shortage, automation demand has increased significantly.”

Adelman agrees. “It wasn’t so long ago that selling automation with 10 to 15% of our systems was considered a good year. Today we’re looking at 40%, and expect this to be at 60% or more going into next year.”

These statements extend to the tube-processing side of BLM’s business. Adelman says many shops are opting for tube-cutting machines that can accept a huge bundle of material and automatically feed the machine one tube at a time. Taking that one step further, the company has developed a cassette-style storage and retrieval system. “It’s not unlike a tower, in that you can load it with large quantities of raw material in different shapes and sizes. Our standard system accepts up to 10 cassettes, but customers can easily expand that to whatever they need.”

Unlike flat sheet, the tube world has far more variables. “Here, you have different profile types—rounds, squares, rectangles and so on—along with various thicknesses and materials,” he continues. “At the end of the day, though, we’re still able to automate it.”

Such automation extends to tube bending. This environment is similar to what other manufacturers have described, where a robot not only presents cut pieces to a CNC laser, but also manipulates the parts (or the laser) in multiple axes to cut the complex shapes required in this market. And in some cases, combination “all-in-one” solutions manage the cutting and bending in a single machine, or even integrate it with flat sheet processing (BLM’s LC5 is one example).

“We also have laser cutters with automation on the back side of the machine but open on the front,” Adelman adds. “These are great for job shops and other low-volume, high-mix manufacturers, who might need to run prototype or low-volume jobs during the day, but want to switch to unattended processing after hours. This solution provides the best of both worlds.”

IPG Photonics Corp. of Marlborough, Mass. is another solution provider serious about fiber lasers. In fact, founders Valentin Gapontsev and Igor Samartsev were pioneers in this area. John Bickley, director of sales and marketing, will tell you the company offers automated laser systems that cover the aforementioned cutting and welding needs, as well as cleaning, drilling, marking, cladding and brazing.

“Within our automated laser systems product offering, we have roughly six different families of equipment that tend to be divided by the size of the parts that people want to process, the type of machining and the required precision,” Bickley says. “For instance, if someone is looking for a highly accurate system, then a traditional Cartesian platform with an X-Y-Z stage will generally provide the best results; for faster speeds and very large parts, however, a robotic system is often the preferred approach.”

IPG Photonics is happy to tackle these and whatever other applications come its way. The challenge is when a customer wants a general-purpose laser that can cut one day, weld another, and mark or clean the day after. As any expert will tell you, laser systems are typically designed for a single purpose—cutting or welding, for instance—while the Swiss Army knife approach is not yet a reality.

That said, IPG does build custom systems with interchangeable process heads, allowing customers to switch between one application and another. “Here, we might include a pneumatic tool changer and a laser-beam switch to route the laser source to the appropriate processing head,” Bickley says. “Where it gets complicated is when you need to use different process gases and fume extraction to support the lasing process. And yet, laser prices have dropped substantially over recent years, so there’s less motivation for shops to invest in a single, do-it-all machine. Still, it can be done.”

Those shopping for bespoke laser systems have many boxes to check, he adds. Parameters include:

These and other factors help determine pricing and performance (speed, accuracy and flexibility). Another important consideration: Will the system still be a viable solution a few years from now?

“Once you’ve put your arms around these variables, the ideal equipment configuration becomes much clearer. But it’s also important to note that, as you add more complexity to the equipment and the application, it’s critical to work with a supplier that has experience in the development, modeling and virtual simulations of both the equipment and the interaction with the process to reduce design iterations and accelerate time to first part.

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