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Performance Breakthroughs Drive Laser Marking

Geoff Giordano
By Geoff Giordano Contributing Editor, SME Media

While laser marking and engraving are well-established processes, innovations and investments in the sector are continuing to push performance boundaries.

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A MECCO turnkey laser marking system.

With more industries bringing laser marking in-house, faster systems with higher wattage and bigger bed sizes are in high demand. Key components in laser marking advances are proprietary software and connectivity that are offering previously unavailable marking options or far smoother integration into production processes—particularly on-the-fly applications.

And, with brand protection an ever-present concern, marking of date codes, serial numbers and other identifying data on vital components helps protect manufacturers from the liability of counterfeit parts and offers quality assurance to customers.

For example, FDA-required unique device identification (UDI) codes track and trace medical devices. Another key advantage of laser marking is on-the-fly identification of parts in constant motion. Inks can’t always fulfill that need, and can also create clogging problems and, as a consumable item, must be managed. Lasers eliminate those issues.

New Opportunities

When Dapra Marking Systems brought on laser industry veteran Dave Noonan as director of laser sales and applications, the goal was to take advantage of emerging opportunities by offering a one-stop solution providing everything from the laser to fume extraction and automation.

Dapra (Bloomfield, CT), offers two eye-safe Class 1 laser marking lines:

  • The cabinet-based 500d is available with a variety of lasers: fiber of 10–50 W, diode-pumped solid state (DPSS) at 6– 20 W, and green or UV lasers.
  • The fiber-only 400i cabinet system is available in 20–100 W.

Both cabinets measure 36″ wide × 38″ tall (914 × 965 mm) to facilitate marking small or large parts, with a 24 × 32″ (610 × 813 mm) sliding head for easy access and a 12″ (305 mm) viewing window. The systems can feature additional axes (Z, X-Y platform) or a variety of rotary devices for marking round parts.

For longer parts, Dapra can build a custom cabinet with a wider opening, powered doors and a programmable Z axis, or put the marking head on a slide. Dapra also makes unenclosed Class 4 systems, which might be more efficient given the application but require appropriate precautions to protect eyes and skin.

“We’re not just walking in to our customers with a couple of boxes and saying, ‘We need your application to fit,’” Noonan said.

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This part marked by a Dapra unit shows the ability of the laser to accurately mark on an arc and locate a 2D mark between the teeth of a gear.

While metal alloys remain easy to mark, challenges remain with plastics because “there is no such thing as a basic plastic,” he said. “Some react better than others; some may take a green laser, some may react with the UV. That’s where we need to consult with customers and run some processes and let them see the reactions with the different lasers. Oftentimes I see marks I may not think look great but the customers rave about them, and vice-versa.”

Dapra ensures its customers learn everything they can about how laser marking might—or might not—be appropriate for certain applications. For instance, marking a high volume of round parts might not be the best fit. Noonan stressed that understanding all project parameters—the type and depth of the mark, the material being marked, and wattage and lens requirements—is critical to Dapra’s service.

In addition to medical, military and aerospace traceability applications, Noonan said the oil and gas industry is looking beyond dot peen marking to laser marking, partly due to laser prices dropping as much as 50% over the past 10 years. “There are many small parts—say 20 lb [9.1 kg] or less—that have to be processed. They want a nicer, cleaner, higher contrast look with more depth than they can achieve with a pin marker. One customer needed marks 22 thousandths deep, and you cannot achieve that with any other marking method outside of laser.”

Laser marking also avoids the problems of ink jet marking mentioned earlier. And costly steel dies and roll markers that can wear or break are giving way to the superior laser aesthetic in the firearms industry, which is required to mark serial numbers at a minimum of 0.004″ (0.1016-mm) deep. Dapra is acquiring a federal firearms license so gun makers can send them firearms or components for testing.

Adding Color to the Mix

With an ability to produce color in its laser markings with just the beam, Cajo Technologies (Kempele, Finland and New Orleans, LA) has spent the past two years gaining a foothold in the US. Like other companies, the fiber lasers at the core of its systems are expected to last 100,000 hours, or about 11 years in service.

To achieve color, Cajo, founded in 2010, does not pre-treat materials with additives like pigments before treating them with the laser, said President Ismo Rantala. “We don’t heat the material. Because of the precision of the laser we change the molecular structure of the oxide layer. Colors are just frequencies, so we change the frequency that reflects from the surface.”

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Laser markings on aluminum by Cajo Technologies, whose systems can mark in color.

Proprietary software—CajoMark and CajoCad—and controllers are key to Cajo’s capability. “We are using off-the-shelf components, but our own mixture of them,” Rantala explained. Many customers are still learning about the possibilities of Cajo’s method. “We have a customer who is starting to use colored American flags on their products. Now the company is looking at doing camouflage marking. They use different metal parts, and paint does not stay on, so we did samples for them.”

Other applications could include using different colors to identify components like dental drill bits. Or, a business might need different colors for its logos to represent different divisions. Unlocking the secret of marking in color by carefully controlling beam parameters has also facilitated Cajo’s ability to quickly mark a growing range of challenging materials.

In a recent test for another potential customer, Rantala executed samples of marks on four types of paint layers. By fine-tuning the beam, he added a logo and text without breaking the paint layers. Another customer makes sunglasses from polymers without additives. “Usually, the laser just goes through” such materials, he said. But by dialing in the Cajo system to produce microscale “bubbles” in the material, Rantala executed the required markings.

Like other marking specialists, the overwhelming majority of Cajo’s sales are in fiber lasers, which can handle almost all materials except more organic or softer and delicate items (such as PCB boards, silicone, and softer plastics), which are handled by Cajo’s pulsed green lasers. CO2 remains vital to Cajo’s inventory for marking organics like wood, leather or rubber, or for engraving glass.

Cajo marks a lot of wiring insulated with soft polymers, including a type of cable used only inside gas tanks. “It’s a really different type of material, and only the green laser works on it,” Rantala said. Green lasers also can replace costlier UV units for many applications, he added.

Cajo units can also perform on-the-fly marking, whether on rolls of the aforementioned cables or on metal bars and aluminum extrusions. “The process is so fast and the marking need is so crucial” that inks can’t always do the job, Rantala said. “One customer said 90% of its downtime is because of its ink machines,” which have to be continually refilled—not ideal when parts move at 3.3 fps (1.0 m/s).

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An operator programs MECCO’s EtherMark system.

Easing Integration

For Pittsburgh-based MECCO, it’s not just about the types of lasers being used to mark—it’s how laser systems are integrated into evolving manufacturing environments. “Fiber technology has taken over most of the applications,” said Dave Sweet, president. “We have a diode-based laser for certain plastics. We look at different wavelengths for different materials—but we’ve been doing that for 20-plus years.”

For him, it is about “how technology is being applied and adapting to changes in manufacturing”—namely automation and the demands of Industry 4.0, or smart manufacturing. Innovation is coming through integration of lasers in the so-called connected enterprise.

MECCO’s solutions focus on seamless connectivity of its SMARTmark Laser Marking Systems on the manufacturing floor. “Several years ago, MECCO, like everyone else, would come to the party with a laser tethered to a computer,” Sweet explained. “It used a Windows-based interface that was good for many customers that had an operator in front of the machine or were calling up many job files and tweaking on the fly.”

But suppose users are marking a simple bar code with a few lines of human-readable characters on hundreds of thousands or even millions of parts a year. If trying to send that information to a laser through a computer and interface from a database or programmable logic controller (PLC), users have to write custom code, Sweet said. At that point “that laser is not part of the manufacturing floor—it can be very cumbersome.”

In response, MECCO released an all-EtherNet/IP interface “so PLC programmers could take control and send dynamic information to our machines using EtherNet/IP or Profinet,” he said. We’re not requiring them to learn our software or spend significant time developing programming language to communicate. It’s all in their native language.”

This answers a key concern of many users of legacy MECCO equipment. “Every time they wanted to change the program or data, they had to get IT involved,” Sweet said. “Manufacturing engineers don’t want to go to IT because guys on the manufacturing floor are thinking in terms of seconds and minutes to get something up and running or making a change to a system. IT thinks in a different cadence; it’s hours, days or weeks to solve a problem. Our customers don’t have the time and don’t want a system that’s so complex that they can’t support it.” EtherNet/IP allows in-situ changes to be made in minutes, eliminating hours of programming time.

MECCO systems also provide fail-safe operability—for example, with vision detection systems that prevent an operator from manually loading and marking an incorrect part. A medical client had been inspecting parts by hand; the MECCO capability enabled automatic inspection of mark quality in the workcell.

Customized workstations might also include “pick-and-place” robots and save floor space versus older diode-pumped water-cooled systems. In the case of the medical customer, MECCO’s fiber-based system takes up about 25% of the previous equipment’s space and reduces cycle time by about 40%.

In some applications, such as automotive diecasting facilities, protecting marking optics and other components from debris and heat is an added challenge. In response, MECCO has provided more sealed work chambers and in-unit air conditioning.

In terms of the lasers alone, MECCO might employ a 50-W unit over a 20-W unit to speed marking time. The company’s portfolio includes fiber lasers ranging from 10 to 300 W for marking most metals, plastics and ceramics and CO2 lasers of 10–100 W. For the past two years, its 5-W Tiburon diode laser has been of great interest, particularly for marking automotive plastics. Whereas a fiber laser will create a khaki color on the workpiece, “because of the high peak energy that the diode laser generates, it absorbs that and gives a nice white color and brighter contrast,” said Sweet. To expand its plastics marking repertoire, the company is exploring green, UV and other wavelengths.

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Direct stainless steel marking with Epilog’s fiber laser and rotary attachment option.

Galvo vs. Gantry

The configurations of laser marking systems are also changing. For example, when Epilog Laser (Golden, CO) introduced its G2 galvo laser system, it was quite a break in precedent for the company, which previously had offered only flatbed, gantry-style laser markers with X-Y plotter mechanisms moving the beam across the work surface.

The G2 achieves marking speeds up to 10 times faster thanks to high-speed rotating mirrors that direct the beam, according to Mike Dean, vice president of sales and marketing.
While the G2 employs fiber lasers of 30 or 50 W, “Epilog stands apart with our CO2 laser sources, which are metal/ceramic laser tubes manufactured in our facility in Colorado,” Dean noted. “Our laser tubes combine a long life, easy serviceability and the ability to engrave at higher speeds with higher resolution. The machines have a very industrial build with memory in the machine, which adds the ability to resend jobs directly from the keypad and to change your speed and power on the fly. We also have Ethernet connection built into the system so you can network your lasers throughout your facility.”

In addition to industrial traceability needs, “we also see increased laser utilization in educational facilities: schools, maker spaces, libraries and STEM programs,” Dean said. “It’s the perfect tool for students to use in all types of classes. Many universities are also adding large maker spaces to their campuses as well, which is a great draw for recruitment.”

While software can increase connectivity on the manufacturing floor, “we also believe the next several years will bring about software and design changes that improve the interface for users to make it easier to design their products,” Dean stated. “As laser technology becomes more affordable and accessible, there will be increased demand for more user-friendly interfaces that make laser technology easier to implement.”

3D and User-Friendly

At Photonics West in San Francisco on Jan. 30, Trumpf Inc. (Farmington, CT) announced one of three new marking lasers coming this year that will produce not only flat marks but marks on contoured surfaces.

With the high-end TruMark 6030, “we can shorten our process time in marking about 25%, delivering a complete solution with new features in quality control and image processing, for example for UDI applications,” said Ralf Kimmel, managing director. “An available programming system simplifies process setup, helping users who are not laser specialists navigate marking on complex surfaces like tubes.

The technical challenge of marking on 3D surfaces is that as height varies, the beam’s focal point is constantly moving. “Having a stable focal point on your workpiece is required for a good result, so the focusing lens in the scanner has to move as well,” Kimmel explained. While 3D scanners are not new, by marrying that capability to equipment that meets today’s high-speed marking requirements, “this machine can do a movement up to 30 mm with every shot. Now, we guarantee the same quality in marking 3D parts as we have with flat parts.”

Signaling a push to make its marking systems even more user-friendly, Trumpf touted its MyMarkingLaser campaign, emphasizing the company’s commitment to help customers optimize marking systems for their needs and integrate them into Ethernet-based manufacturing networks.

 

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