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Laser Marking: Going Places

Geoff Giordano
By Geoff Giordano Contributing Editor, SME Media

Laser marking goes under sea, under surfaces and ultrafast.

Continued innovation is particularly important to Finland-based Cajo Technologies because of the demand on its systems for marking subsea cables between oil rigs and the mainland. These plastic-coated cables (spooled in main photo, with details in inset photo) can run up to 49 miles (80 km). (Provided by Cajo)

The well-established field of laser marking continues to break new ground with expanding business opportunities in automotive, oil and gas, medical and other industries.

Ultrafast lasers—those in the picosecond and femtosecond regime—are emerging as key players in some particularly delicate, federally mandated medical applications. New proprietary software versions and customized marking systems are in increasing demand. And a major new partnership between one relatively young system provider and a global leader in wires and harnesses further demonstrates the robust momentum of laser marking.

And, in keeping with the drive toward Industry 4.0, new automation measures are being rolled out to increase the throughput of laser-marked products.

Ultimately, while decorative laser marking has been in use for some time, the growing need for brand protection via track-and-trace marking of complex codes on a broad range of high-value parts makes the technology more vital than ever.

Growing Together

For Finland-based Cajo Technologies, 2019 is shaping up to continue last year’s momentum with a new sales and distribution partnership with wire and harness giant Anixter, as well as expanding work with subsea cables.

Those industries rely heavily on speedy on-the-fly marking, which remains Cajo’s fastest-growing application, according to President Ismo Rantala. In business since 2010 and with U.S. headquarters in New Orleans, Cajo touts itself as the fastest laser marker in the world—which clearly caught the attention of Anixter.

Anixter “is the largest wire distributor in the world,” Rantala explained, “and they stock over $1 billion of wires around the world.” By bringing Cajo’s expertise in-house, Anixter adds value for its customers, who can obtain either pre-marked wires or a Cajo marking system direct from the wire supplier.

“The wire-and-harness industry has found out that on-the-fly marking is the future of marking anything they do,” Rantala said. He noted that 90 percent of downtime in marking applications is typically due to the failure of clogged ink machines. In contrast, lasers don’t have consumables and can run
100,000 hours, he said.

Meantime, Cajo—which is selling primarily to OEMs—is beefing up its proprietary software suite, putting them in the same realm as Trumpf and Rofin. The company’s newest design offering is CajoCAD 3.0. In fact, Cajo’s hiring priority at the moment is software engineers, Rantala said, with the aim of continuing to improve wire marking speeds based on specs requested by the industry’s biggest wire manufacturers.

Continued innovation is particularly important to Cajo because of the demand on its systems for marking subsea cables between oil rigs and the mainland. These plastic-coated cables can run up to 80 km (49 miles), as in the case of the fiber-optic power and fluid lines produced for the energy industry by Norway’s Aker Solutions. Multiple individual cables can be housed within a larger cable.

For Aker, Cajo created a three-laser marking cell that makes marks at 120o increments around the cable, so the marks indicating project name and cable length can be seen from any angle. Since the fiber optic cables cannot twist and function properly, a single marked line on top ensures they remain in their proper orientation. Other markings indicate the distance a particular portion of the cable is from the ship, rig or mainland. “That’s for troubleshooting; if something happens with any cable, they can ping where the error is and go fix it.”

In terms of the lasers in its systems, Cajo relies on fiber units, which can mark “99 percent of materials,” Rantala asserted. “We can mark lay line and sequential marking for the subsea cables on PVC and other materials with lasers, and that’s been turning heads among companies that are doing these products.”

Short and Sharp

Rotary workstations are available in two- or four-position configurations to allow for faster through-put. Operators unload the previously marked parts and reload additional parts while the laser is marking within the Class I enclosure. (Provided by Mecco)

On a far smaller scale in terms of part size, the medical community is beginning to embrace ultrafast, or ultrashort pulse, lasers in the picosecond and even femtosecond regime to mark permanent unique device identifiers (UDIs) on stainless steel devices.

While nanosecond lasers have been successful in marking products for some time, noted Thorsten Ferbach, business development manager for Coherent-Rofin, Santa Clara, Calif., their impact on stainless steel can lead to corrosion with repeated autoclaving. So, while picosecond lasers are a significant investment, they more than pay for themselves in the manufacture of high-value medical devices—where a failure is never an option.

Driving this technology is the FDA regulation that went into effect in September 2018 stipulating that medical devices requiring multiple rounds of sterilization bear marks that will not degrade over time. The regulations are intended to guarantee that doctors around the world can access the data encoded in these marks. Failures at reading these codes generate records within the FDA database, Ferbach explained, and too many reports for a given product can result in the FDA shutting down production as part of a major investigation.

To satisfy this demand, Coherent-Rofin has been optimizing its Rapid NX picosecond laser, Ferbach explained. Unlike nanosecond lasers, which produce dark marks by creating black oxide on the surface of a material, picosecond marking alters the subsurface nanostructure of material like 1.4301 stainless steel, thereby trapping and absorbing light to produce high-contrast marks.

“It is similar in principle to the protective skin of stealth fighter jets,” Ferbach explained. “When you expose that skin to radar beams, there is no reflection; the plane becomes invisible.” With a stainless-steel device, the areas treated with the picosecond laser absorb light to appear as dark marks. And unlike an oxide mark, which can change in appearance depending upon the angle at which it is viewed, the black subsurface mark looks the same from all angles.

In terms of throughput and the ability to monitor the marking process, there is no difference between the nanosecond and picosecond laser in this application, he noted. But before a customer gets underway with a project, Coherent-Rofin will conduct a feasibility study. This ensures the picosecond laser is operating under the correct parameters for the job and that the customer understands preventive maintenance measures for these internally water-cooled units.

Outside of medical devices, other industries have the potential to embrace the precision of ultrashort pulse lasers for marking.

Contemporary kitchen design, with its focus on stainless-steel appliances, is an ideal candidate, Ferbach noted. “You see stainless steel items are either etched or printed,” he explained. Manufacturers in this industry avoid nanosecond lasers at present because of the aforementioned variability of how black marks appear when viewed from different angles. “This is where we still have to educate the market” as to the benefits of ultrafast lasers.

Besides appliances, he continued, consumer electronics OEMs are also embracing ultrafast.

In terms of materials, picosecond lasers can also mark on titanium, especially for implants; anodized aluminum, often used in orthopedic devices; and PEEK and PPSU plastics.

Expanding Portfolio and Markets

Dapra Marking Systems of Bloomfield, Conn., began making its own laser systems about two years ago to capitalize on multiple opportunities, ranging from large OEMs to small custom fabricators. From low-power devices to the relatively high marking power of 100 W, Dapra has further expanded its offerings with a new fiber-based green laser and picosecond line.

Mecco often configures workstations with features that meet specific needs, including barcode scanners, safety touch buttons and part fixtures. (Provided by Mecco)

“We jumped on board and began offering picosecond lasers because when you have the right application and only picosecond will do it, it’s a nice fit,” said Dave Noonan, director of laser sales and applications. “Think of UV marking as cold marking because there is a very small heat signature. With picosecond lasers, it’s like that on steroids.”

The company is also offering an enclosure with a programmable slide mounted to the back wall. This X-axis slide allows users to move the laser head across a much larger distance. A typical slide allows for movement of 30″ (762 mm), Noonan explained, allowing the marking of either more parts or very long parts like a rifle barrel or series of barrels. This is in contrast to more customary square marking areas of roughly 110-170 mm.

Meantime, a new addition to Dapra’s software suite allows faster rotary indexing of cylindrical parts like surgical tools. “If you’ve got a probe and you need rings laid on the probe to know how deep it is going into the tissue, these rings have to be put on in a very consistent manner,” Noonan explained. “A typical ‘third-axis’ for marking rings requires that you mark and then index; it doesn’t allow you to do both at the same time. (Our new software) does let us mark and turn at the same time,” overcoming a longtime struggle for manufacturers, and at less cost than true on-the-fly software.

In addition to its software options and customized cabinets, Dapra has developed a new controller that can be dropped into any of its cabinets for any laser power. “It’s very modular in nature,” Noonan said. The same controller is used for Class 4 offerings as well, which have become quite popular.

Dapra’s systems have quickly found adopters for medical, aerospace, automotive, gear manufacturing and heavy agricultural equipment applications.

“Aerospace is a sector that was quite hot last year and looks to be going red hot into this year,” he noted. The industry has historically leaned toward dot peen marking, he added, given regulations that dictate low-stress marking. “We’re seeing a surge in interest from the aerospace industry in marking a greater number of parts and much larger projects coming.”

While those projects tend to come from larger players, smaller custom fabricators are also coming to the fore—which is prompting Dapra to introduce a product line to meet their needs.

“I was just at an installation in Florida where we sold a laser to a small medical manufacturer” with only one-and-a-half employees, he recalled. “He is making traction pins, surgical trays, bone screws and more. In the past, lasers were too expensive for a small player like this; not any longer. It’s a new world and we have relevant solutions.”

As laser prices come down, Noonan said, Dapra expects an even bigger year in 2019 as more manufacturers are able to add laser marking to their repertoire.

One notable growth area has been in the automated marking of plastics, he said. One injection molding shop is “pulling anywhere from two to four parts out of a mold and presenting them one at a time to an in-line laser for marking a datamatrix.” The system confirms the readability of the marks before the parts are taken away or, if unreadable, the system actuates a sequence to execute a second mark.

And, over the past year, gear manufacturers have turned to Dapra laser marking systems in place of dot peen to cut their costs “greatly, and they are thrilled with the production value that lasers have brought to the table.”

While dot peen marking is less costly, it brings with it issues of part holding and wear of the carbide marking pin with resulting degradation of marking clarity. “The non-contact method of laser marking is really superior and being embraced for good reason: You don’t have parts that wear out, and your marks are incredibly repeatable and reliable.”

Data-Driven Solutions

Pick-and-place systems allow automated batch marking by incorporating a robotic arm within the enclosure to transfer parts to and from the laser marking system.
(Provided by Mecco)

Tracking all that marked data is as important as making the marks, and the back-and-forth transfer of critical information between software and marking devices is a key element in system design.
Creating and securing that bi-directional chain of communication is essential for allowing manufacturing engineers and those responsible for maintaining productivity on the floor to track relevant data, asserted Dave Sweet, president of Mecco, Cranberry Township, Pa.

For instance, in laser marked aerospace components for Honeywell, “we are getting variable data from a system database. Enterprise software is sending us that information, and we are not only marking the parts but also using vision systems to verify that the information we marked on the parts matches what had been sent to us.” Mecco’s system then generates a report that is stored for the government to register those UDIs.

According to Mecco’s case study of the Honeywell project, the 20 W SMARTmark fiber laser system “plugs in anywhere using 120 VDC and occupies half the footprint of the old YAG flatbed.” Also, marking-related quality notifications and returns that had cost $2,500 per incident have dropped significantly.

In the automotive world, Sweet noted, safety-related parts and those of certain dollar amounts get unique identifier marks—all tracked to the vehicle identification number. This includes camshafts, crankshafts, blocks, transmission cases and even connectors. After marking those components with bar codes, those “parent-child relationships” are logged into a database that eventually ties all that information to the VIN.

Marking system connectivity increasingly extends to operating alongside collaborative robots, or cobots. MECCO recently installed a system that uses a cobot to pick up parts from a tray then hold them for scanning by a vision system. The vision system sends information to the laser marker, then the cobot brings the part to the laser for marking. After one side is marked, the cobot brings the part to a camera to verify that the marks are accurate before each other side of the part is marked.

“The need for traceability is still growing,” Sweet said. “Customers are looking more for solution-based systems than just a laser in a box,” meaning the market for modular, configuration-based approaches to meet increasingly specific needs for manufacturing flexibility will continue to grow.

Mecco generally bases about 80 percent of its systems on four basic enclosure sizes to which can be added rotary dials of 6, 18, 24 or 36″ (152, 457, 610 or 914 mm) that continually circulate fresh parts to be marked. Each enclosure also has the option of an X-Y table. The other roughly 20 percent of Mecco’s systems can be customized, including with stripped-down graphical user interfaces that let operators load and monitor jobs.

For instance, a recent tool manufacturing customer needed to cover a 30 × 30″ (762 ×762 mm) tray of parts, which required Mecco’s extra-large enclosure and X-Y-Z gantry system. “Instead of them having to buy multiple lasers, they were able to buy one laser, load this system, hit go, and walk away.”

In another case, a water meter company used a combination of dot peen and laser marking with a four-position rotary workstation. A brass housing had a serial number marked with dot peen, and a laser duplicated that serial number on the black plastic lid.

Proper system design clearly pays off, as in the case of a medical customer of Mecco’s that upgraded from older diode lasers to a fiber system and saw overall machine cycle time drop from 18 seconds to less than 11 seconds, with better mark quality that allowed better visual inspection with hand-held scanners.

Add to that the fact that Sweet sees more small shops investing in robots to accompany their systems, and it is clear that laser marking has become and will continue to develop as a robust and indispensable industrial operation.

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