Photo courtesy Trumpf Inc.
Laser Cutting and Welding
Laser metal deposition process from Trumpf enables manufacturers to coat a durable surface onto metal parts for corrosion resistance in harsh environments.
Laser Cutting and Welding Technologies Advance New techniques in laser cutting and welding are opening doors in automotive and medical manufacturing applications Patrick Waurzyniak Senior Editor
aser technologies for cutting and welding parts have been steadily refined since the laser was invented some 50 years ago. Today, laser technology is easily used to quickly cut 2-D or 3-D sheetmetal parts and to make high-quality welds. The flexibility of lasers has
led to adoption of robotic laser processing and five-axis laser cutting and welding in many areas, including cutting the newer high-strength steels in today’s automobiles and cutting and welding processes used in medical device manufacturing.
Laser Cutting and Welding Advances in lasers’ power, improved cutting speeds and
ods of handling newer steels that are too difficult to process
edge quality, and lower operating costs have opened more
with typical stamping operations. “For us right now, the big
avenues for use of the technology. Gains in power, speed, and
growth is in automotive components,” notes Joe Camp-
laser beam quality during the past decade have helped manu-
bell, vice president, Robot Products Group, ABB Robotics
facturers use the systems in more areas, and better beam
(Auburn Hills, MI). “That’s where all the market forces come
quality also reduces the need for secondary operations.
into play—brutal competition, they’re moving to high-tensile strength steel, and they have to go deal with the manufacturing process. We have a couple customers who are starting to figure out that it [robotic lasers] could be used as an offensive tool. It’s not just, ‘I’ve got to do this because the guy sent me the spec on the material.’ They’re starting to figure out that it may be a better manufacturing process.” Using robotics for laser processing can offer manufacturers advantages over much more expensive five-axis laser systems including lower costs and greater flexibility, according to Campbell. “There’s a convergence of multiple technologies that finally gets to critical mass. The automotive manufacturing business is kind of brutal—it’s cost per part. They’re really not interested in how sexy your stuff is. But there’s been a combination of improvements, in the lasers themselves, the delivery vehicles, the heads, the robots, the software—everything’s been incrementally improving to the point where we’ve got a very nice package, which has fueled some growth. And
Photo courtesy ABB Robotics
then there’s been a pretty significant change in a lot of the material or the metallurgy going into vehicle components in order to get weight out. These lightweight, high-strength steels are great, but they’re hell on die sets.” If automotive manufacturers had a choice, they would stamp their parts, contends Doug Hixon, ABB robotic laser Robotic laser processing with an ABB IRB 2400 robot and an IPG fiber laser offers speed and flexibility cutting a Tier One supplier’s boron-alloyed B-pillar automotive body component.
cutting and welding specialist. “If the Tier Ones could trim and pierce features within their current forming process without accelerated die wear, they would do it in a heartbeat, but currently laser cutting is their best option,” he adds.
Newer applications include more widespread use of
Automakers need to quickly process higher volumes of
lasers to cut the automotive industry’s latest hot-stamped,
hot-stamped parts, leading some suppliers of five-axis laser
lightweight, ultra-high-strength steels (UHSS) that are be-
systems to introduce systems specifically tailored for laser
ing used to make smaller, more fuel-efficient automobiles
cutting of UHSS auto parts. Laser systems builder Trumpf Inc.
much stronger and safer than earlier models. Lasers can
(Farmington, CT) recently introduced its new TruLaser Cell
efficiently cut the hot-stamped steels and hydroformed
8030 five-axis laser cutting system, and in May, the company
parts that make up some of automotive’s strongest sheet-
announced an order for 50 of the TruDisk fiber-guided laser
metal components, such as car and truck A and B-pillars,
machines to be delivered to Volkswagen AG for use in VW’s
as well as dashboard structures.
Wolfsburg, Germany, headquarters, and at other sites.
Robotic laser processing on UHSS components has made
“What the automotive industry is faced with is that the
inroads in recent years, as has five-axis laser cutting of these
customers are demanding smaller, lighter, and safer vehicles
critical components, as automakers seek more efficient meth-
with better fuel mileage, and one way to accomplish that task
is by the use of ultra-high-strength steels,” states Frank Geyer,
small cars have a greater percentage of the ultra-high-strength
product manager, five-axis laser systems, Trumpf Inc. (Farm-
steels than they used to have, they have an increased volume
ington, CT), “because with conventional steel you would have
of parts per vehicle, and so high productivity is crucial to help-
to use more material, making small cars heavier and slower.
ing meet the ever-increasing demands of customers.
“In the hot-forming process, a special ultra-high-strength steel is used for the blanks; those get heated up to about 900°C, formed, and then quenched while in the die,” says Geyer. “What that does is it arranges the grain structure and makes the part extremely hard and stiff. The resulting sheetmetal parts are of very high strength, and that leads to a dilemma—because of their properties, they cannot just be blanked or cut conventionally. Due to their martensitic structure, the ultra-high-strength steels are so hard that a conventional blanking die wears out after about 1000 hits, making the process uneconomical.” In comes the laser, which is cutting with light, with no wear on the tool itself, Geyer notes. Over the years, lasers have significantly improved in power and beam quality, he adds. “The combination of these high-power lasers with high beam quality and high-performance five-axis systems has evolved into a solution with the TruLaser Cell 8030 that was developed for the hot-stamping business. Typical customers are Tier One suppliers that provide the stamped panels or even the completely welded bodies to the automotive manufacturers.” The automotive market requires very high productivity, output, and flexibility, says Geyer, adding that here the fully programmable five-axis laser systems have many advantages over conventional systems. “You don’t have degradation of the tool, for example, like with conventional die blanking—those tools wear out and your product changes, and with the laser it does not. The cutting process is very consistent and efficient. As
Laser Cutting and Welding “High productivity also usually brings down the costs of the operation. That’s where the TruLaser Cell 8030 equipped with the TruDisk, a solid-state laser with a fiberdelivered beam, comes in play. It has a small footprint, is very fast, and it consumes significantly less energy than conventional systems, compared to CO2 systems.” The Trumpf TruLaser Cell 8030 system comes standard with a 3-kW laser resonator, with a 4-kW resonator available as an option. Cutting UHSS materials doesn’t necessarily require higher-power lasers, Geyer notes. “Typically, the thickness of those materials rarely exceed 2–2.5 mm, so the materials themselves do not require a higher-power laser, and the complexity of the 3-D component limits the cutting speed. You can’t just go with full speed, like with flat-sheet cutting,” he states. “You have process speed limitations when cutting complex 3-D geometries. A 3-kW laser is efficient enough to cut about 90-95% of the parts. If the part has a very simple geometry, a 4-kW laser can give you a little more of a speed advantage. Going for a 5 or a 6-kW laser is not going to give you any advantage, because you’re simply not reaching a higher processing speed; the laser would be just too powerful for what you can do.”
“These lightweight, high-strength steels are great, but they’re hell on die sets.” For welding, Trumpf also offers its laser metal deposition (LMD) process that welds powder on a metal surface for components used in harsh environments. “These applications are where you need to tailor the surface of a part, specifically for corrosion or abrasion resistance, and include industries such as the petrochemical and offshore industries, and the turbo engine industry or agricultural. These are the types of companies that make components and use components that see a lot of abrasion and corrosion,” notes Dave Locke, LMD applications manager. “It’s a technology that’s been around a long time, but with the advances that we’ve seen in the last handful of years, specifically the fiber-delivered lasers and higher powers, it’s suddenly made it much more practical to do a lot of powder deposition in applications that have always been there, but in many cases, haven’t been economical.” Hot-stamping of boron steels began in Europe, where it was introduced in the 1980s by European automakers initially for production of side-impact beams, notes Terry L. VanderWert, president of Prima Power Laserdyne (Champlin, MN). The process has since gained momentum in other regions, including North America. Prima recently announced it has expanded its Minnesota facility to handle final assembly, test, and customer installations of its Rapido Evoluzione five-axis system that can quickly trim and cut features in hot-stamped automotive components. With its fiber laser, the system offers users rapid traverse rates of 175 m/min, and is said to be capable of cutting and trimming an automotive B-pillar in under 50 sec. “The steel blanks are heated to 900°C or higher, formed at near this temperature, and then cooled in the die. The high hardness of the formed parts makes traditional metal trimming or punching impractical,” VanderWert says. “The five-axis laser is the tool of choice for that application, because of its speed and flexibility, because there are relatively high volumes because of the automotive levels of production.
Laser Cutting and Welding “North American manufacturers were slow to adopt hot-stamping, because we had larger cars and fuel wasn’t that expensive relatively,” he adds, “and as soon as the focus turned to more energy-efficient yet safe automobiles, they found the need to adopt the hot-forming process. Within the last couple years, the rate at which hot-forming is being used has clearly accelerated. Today, you will find hot-stamped parts in virtually every car and truck manufactured worldwide.” More use of fiber lasers is an ongoing trend in the laser Photo courtesy Cincinnati Inc.
industry, VanderWert notes, and the current Rapido system was designed around this application, both with its size and the performance of the cutting speed. The machine has longer strokes (4080 × 1520 × 765 mm) and can handle a wider size range of components. “We use both CO2 and fiber lasers,” says VanderWert, “but I would say the trend is Powerful lasers like this five-axis CL-850 laser from Cincinnati
toward fiber lasers. They’re faster. It’s all about cycle time,
Inc. easily pierce holes in flat-sheet metalcutting applications.
and ultimately about part cost. The goal in many of these large components is for less than oneminute cycle time.” Fiber lasers continue to gain converts over CO2 lasers due to fiber lasers’ inherent advantages, notes Rick Neff of laser systems developer Cincinnati Inc. (Harrison, OH). Neff, a member of SME’s Industrial Laser Community (ILC), recently moderated an SME webinar, “Industrial Laser Cutting 101,” covering the technical advantages of different laser-cutting technologies. Fiber lasers have a beam wavelength of about 1.0 micron so they can be delivered to the cutting head with a thin glass fiber, Neff notes, while CO2 lasers bounce the beam off mirrors and use bellows that expand and contract to contain and deliver their beam. Beam delivery on lasers has improved, Neff adds. “The focusing lenses are different with CO2 and fiber lasers,” he says. “There are newer compact heads that need to be small as they’re often put on the end of a robot.” For thicker materials, the choice often can be CO2 lasers that can easily
Laser Cutting and Welding cut through thicker, harder metals. “CO2 lasers cut all types of
Improvements in both lasers and robotics has enabled great
materials,” Neff says. “Fiber has a little trouble with translucent
progress in laser cutting and welding over the last few decades,
materials. Fiber can cut thin copper but for something like a 0.5"
observes Michael Sharpe, materials joining engineering, Fanuc
[12.7-mm] bus bar, waterjet would be better be a better choice.
Robotics America Corp. (Rochester Hills, MI). Fanuc Robotics
A 4-kW CO2 can cut 1" [25.4-mm] mild steel with ease.” A key advantage of fiber lasers is the technology’s
developed the first integrated CO2 laser robot, the L-100, back in the early 1980s, Sharpe notes. “It was unique in its day,”
wall-plug efficiency—it’s simply more cost-effective to run
Sharpe says. “That was back when we were GMF Robotics.
than many other laser types. “Fiber laser can be delivered
The first L-100 series was CO2-based, so beam-delivery sys-
in a smaller fiber, so it provides a better beam for cut-
tems were integrated into the robot. It was designed basically
ting than other types of fiber-delivered lasers,” Neff adds.
for tailoring of materials, either tailoring and/or welding, and it
“Fiber and direct diode are much more efficient than CO2
was primarily for automotive OEMs and their suppliers.
in operating costs. While the fiber resonator requires no
“The industry kind of softened for a number of years,
maintenance, the recommended maintenance is about ev-
and then hydroforming came along, in about the late '90s,”
ery 2000 hours on a fiber cutting system. The time to do
Sharpe recalls, “and part of the problem with hydroforming is
maintenance is maybe half that of C02 lasers.”
because you blow the tube up like a balloon you only have so
Costs per 100" (0.25 m) of cutting with a C0 2 can run
many surfaces that can be punched, so it required a machin-
about six cents per cut whereas costs to run fiber lasers are
ing process. Laser machining or cutting in this case was the
about two cents per 100" cut, he adds.
most viable due to the throughput.”
Automakers started using improved steels for crash and
can be awkward to remove it. So right off the machine, you
rollover protection in about 2002, as the quickest way to
can get a finished part by cutting the mild steel with nitrogen,
change the vehicle’s design was to change the material,
with no oxidation layer or coating onto the cut edge. If you use
Sharpe says. “A lot of martensitic or hot-stamped type materi-
oxygen, you’re going to get an oxidized edge. If you use nitro-
als came onto the market with dualphase, there are many different trade names,” he recalls. “But the long and short of it is they’re very difficult to trim in a stamping die, or a trim die. They’re very harsh on tooling because they’re so hard, and that necessitated the need for robotics to do that trimming. “Throughout the industry, it’s been driven primarily by automotive, by those demands for that requirement,” he adds. “Now all along, you’ve had improvements in laser technology. If you look at the latest improvements in solid-state designs and fiber deliveries, they basically brought the cost factor down. And by bringing the cost-quality factor down, now I can do more applications, things such as robotic remote welding.” For laser cutting and for welding applications, laser developer Mitsubishi Laser/MC Machinery Systems Inc. (Wood Dale, IL) offers a wide range of systems, including the company’s most popular 2-D flatsheet cutter, the LVPlusII, notes Jeff Hahn, Mitsubishi national product manager. That system offers a 4.5-kW laser resonator as standard, and the Mitsubishi NX system is available with a 6-kW resonator for higher-power applications. “In welding, we only go up to a 4 kW, and we have two new five-axis machines coming out,” Hahn notes. “For 2-D cutting, the big interest right now is nitrogen cutting mild steel, that way a lot of people are doing a lot of work for the Kubotas and Caterpillars, and they don’t want oxidation on the cut edge, because when they paint it, it’ll chip off, and it
Laser Cutting and Welding gen, you don’t get that. You get a clean, weldable, paintable
kind of like a hybrid word meaning burr on the bottom; when
edge right from the machine.”
you slow down, you can get a burr on the bottom, and this
With the new five-axis machines, Mitsubishi is implementing a full-rotary axis for six-axis, simultaneous movement,
eliminates that.” The new controller also helps with slope control, Hahn
Hahn adds, and the NX laser systems are also offering the
adds, for welding applications. “What you have to do with
new LC30 Mitsubishi control. “We use it on our EDMs and
welding is ramp power up gradually to full power, then
waterjet, it’s going across our product line and we’re migrating
weld, and then ramp it down when you come to the end of
most of the machine tools towards it now,” Hahn says of the
the weld,” he says. “This offers a lot better control for that
control. “Everything’s faster on it, and it’s an NC with PC, so
because the machine will do that on its own, once you set the
we use the Windows GUI interface on it, and you can connect
parameters, so it’s like a TIG welder.”
to hard drives and hook the machine up as a node on a LAN
Precision cutting and welding with lasers is a focus for Miyachi Unitek Corp. (Monrovia, CA), as medical-device
very easily.” In welding, the LC30 also will help users by offering more
manufacturers demand smaller, more reliable, faster, and
of an intelligent control, as far as adapting what’s called
more cost-effective solutions. The company has recently
DRC technology to the parts, notes Hank White, Mitsubishi
introduced new cutting solutions and is broadening its
welding specialist. “DROSS Reduction Control [DRC] helps
access to different industries, notes Mark Rodighiero, the
with most of those parts on the five axis that are thinner,”
company’s vice president, systems, technology, and prod-
Hahn adds. “DROSS, which is what the Japanese call it, is
“We’re broadening our access to different industries,” notes Rodighiero. “Another area is corrosion-resistance marking for medical devices and also for aerospace devices. There are a lot of requirements for medical to identify parts
definitely a movement in the fine laser-cutting industry from pulsed YAG lasers to fiber lasers for those reasons.” In metalcutting, the wavelength is going to be about 1 µm and remain that way, according to Shannon. “In the expanding
with unique identifiers or serial numbers, especially as the FDA directive on medical-device UDI marking is about to be released. So we’re branching out from welding into other areas, developing applications and machine capabilities and going after commercially valuable applications.
“To weld a small conductive part is really, really difficult.” There is a movement from traditional cutting technology toward newer laser cutting technology in a number of areas, notes Geoff Shannon, laser technology manager, Miyachi Unitek. “There’s a migration of looking at laser cutting for tube cutting, for three-axis and five-axis cutting, to look at replacing existing technology for reasons of quality, throughput, and cost,” he adds. “The applications that spring to mind are cutting single-sided features, such as windows or channels on thin-wallthickness tubes, which is a very slow process for traditional techniques, such as sinker EDM.” The laser industry is rapidly moving toward fiber lasers from older processes for a variety of reasons, Shannon says. “In terms of technology migration in the laser industry, there is a movement from the old Nd:YAG technology to the fiber-based cutting technology for basically reasons of cut resolution, control of the laser pulse, speed of cutting, and just the economics of the equipment as well,” Shannon states. “There’s
Laser Cutting and Welding field of micromachining, you will see a shift to different wave-
weld perhaps much smaller parts with finer details. The
lengths, just because you have advantages in the resolution of
pulsed YAG green laser is really a line to conductive materials.
what you can do with those different wavelengths,” he explains.
To weld a small conductive part is really, really difficult, and
“Essentially, as you decrease the wavelength, the spot size that
so the green laser’s perfectly tuned to doing that because the green gives you a real advantage in absorption over the 1-µm wavelength that is normally used with either the pulsed YAG or the fiber. As the miniaturization is kind of accelerated, we feel the green laser will be a great solution for electrical connections, terminal connections, in conductive materials.” Many implantable medical devices have electronics being driven by a battery, he points out. “You have to distribute that power in the battery by bus bars or internal conductors, and it’s those welds that we’re talking about,” Shannon notes. “It’s the interconnects of the power source with the elements with that device that need that power. And all these devices, they’re only going to get smaller, and they’re only going to get more power so they can have longer lifetimes, and we’re talking about a joining process which gives you greater reliability and longevity, and also the opportunity to miniaturize your terminal to less than it is right now.” ME
Photo courtesy Lincoln Electric.
Want More Information? ABB Robotics North America Ph: 248-391-9000 Web site: www.abb.com/robotics Cincinnati Inc. Ph: 513-367-7100 Web site: www.e-ci.com Robotics manufacturer Fanuc Robotics offers laser welding robots like this hybrid laser/arc-welding system through its robotic integrators and laser partners including Lincoln Electric.
you can produce also decreases—it gives you increased resolution, and also it gives you increased pulse control over how the laser affects the material, so your thermal input into the material goes down. Thermal management in small parts is obviously extremely important, so there may be some advantages in those particular applications where you can look to different wavelengths, especially for nonmetals. When you have to optimize absorption in a nonmetal, particularly a plastic, using those shorter wavelengths normally has some advantages for you.”
Fanuc Robotics America Corp. Ph: 800-iQ-ROBOT Web site: www.fanucrobotics.com Mitsubishi Laser/MC Machinery Systems Inc. Ph: 630-860-7824 www.mitsubishi-world.com Miyachi Unitek Corp. Ph: 626-303-5676 www.muc.miyachi.com Prima North America Inc. Ph: 413-598-5200 www.prima-na.com
Micro welding in medical still uses traditional pulsed YAG, but users are looking toward fiber lasers, he adds. “Although many applications remain suited to the pulsed YAG laser, there’s a resolution advantage of the fiber laser in that it can
Trumpf Inc. Ph: 860-255-6000 www.trumpf.com