Laser technology seems to be evolving at an unprecedented pace – the machine tool world’s equivalent of Moore’s Law, which, roughly translated, means that the speed and capability of computers will increase every two years. But, if we take a step back and consider these advancements and what form they take, it becomes apparent that we’re primarily seeing an arm’s race in ever higher laser powers, which begs the question: Is power outpacing technology?
To make a rather poor analogy, putting a 10-kW fiber laser on a platform not designed to harness that amount of power is akin to sticking a supercharger on the family minivan; the desire for speed is there, but the execution is lacking.
Built to last
Companies in the laser space are taking this analogy more seriously by the day, and that is certainly the case at Trumpf. The latest example is when the company’s engineering team was dreaming up the new platform on which the TruLaser 5030 fiber is based: a frame that is incredibly stiff coupled with a drive system that is lightweight, rigid and exceptionally dynamic. The goal was to ensure the highest possible positioning accelerations, cutting accelerations and jerk factors (rate of change of acceleration) that allow the user to harness the immense power of the TruDisk 10001.
While the TruLaser 5030 fiber is exceptionally quick, it’s well understood that possible speed is not the same thing as actual speed. The relationship between the speed of the machine and its base is crucial when processing in real time on the shop floor as opposed to on the showroom floor. If the frame can’t withstand the power of the laser, users can’t get the most out of their laser.
Trust in tech
In addition to the need for rigidity in the frame, the tech embedded in a machine must also be solid and reliable. When Trumpf’s engineering team was assessing the various processing technologies found standard on the 5030, the conclusion was that a new technology would be required – one that could take the data from the individual systems to tie it all together to deliver on overall process reliability.
It can’t be overstated how important it is to ensure that a machine’s systems are properly integrated. In a real-world scenario, the material that goes across the bed of a laser is never in perfect condition. For example, there could be rust on the surface, variations in the material thickness from nominal or an impurity of content. Therefore, the laser must do more than just assault the material with a maximum amount of power available. It must be smart. It must be adaptive.
For example, in many cases, the use of a light mist of water can reap substantial benefits when cutting thick carbon steel with oxygen. CoolLine is a controlled flow of deionized water that extracts heat from the material, enabling smaller webbing to increase sheet utilization, optimize nesting patterns, and increase geometric possibilities and part complexity. It also allows users to deal with poor material quality without slowing down the laser.
The beauty of CoolLine is in its flexibility. It can be used only when it’s needed. An additional improvement to the technology is now available whereby an onboard deionizer is used to remove conductivity from the facilities’ central water supply. No longer does it require a separate container and there’s still no need for any nasty water-soluble oil.
CoolLine isn’t always necessary to get a good cut, even on grungy material. This is a result of one of the biggest technologies introduced to sheet metal manufacturers: BrightLine fiber, which changes the beam diameter and the beam mode. BrightLine fiber allows for an enormous spot size range, meaning that cutting thick materials with a 1-micron laser is simple and reliable.
Rather than using optical manipulation to achieve a large spot size, BrightLine fiber works by switching between two different cores within the delivery fiber. The result is a beam that’s three to four times larger than what can be achieved using optical tricks or mode changes.
Remember, though, that laser users are always limited by the size of the delivery fiber being used, so having a laser with a very small and very large fiber means that there’s no need to compromise. And because the switch happens in about 45 milliseconds, efficiency is not compromised; pierce with a 150-micron beam and cut with a 1,060-micron beam to ensure the best possible processes in every scenario.
It’s important to make sure that the focus position of the laser stays constant, too. Trumpf introduced Smart Beam Control to continuously monitor and respond to the condition of the beam; if the focusing lens starts to drift, the laser compensates automatically.
Along the optical chain, it’s critical on any fiber laser to ensure that the protective glass stays clean. Using a protective glass is an obvious benefit because it’s a lot cheaper to replace a piece of glass than a focusing lens. Additionally, avoiding interaction with the focusing lens guarantees greater uptime by reducing the amount of beam alignments and focus checks that are necessary. Of course, it’s necessary to keep this component clean to be sure the laser is cutting at its best.
Typically, the operator uses their experience to interpret what cutting problems are being caused by a dirty protective glass. A standard feature on most Trumpf fiber lasers is Protect Glass Monitoring, which automates the cleanliness check. In real time, the laser tracks not only if the protective glass is contaminated, but how contaminated it’s become. The laser eventually stops itself before it becomes critical, but what’s handy is the warning the operator receives beforehand. If the operator is alerted that the protective glass should be cleaned before it must be cleaned, it optimizes uptime and process reliability.
Closer to the workpiece is the nozzle. On a 10-kW, 1-micron laser, the nozzle moves quickly, so it may get banged up on occasion. The TruLaser 5030 fiber has 360-degree collision protection. The collision protection system responds so quickly to a collision that often times the nozzle isn’t affected at all, even if there is a bigger bump with a tip-up.
The beauty in having a recoverable, re-centering cutting unit is – post collision – the whole optical chain is ready to get back to work. But what about the nozzle?
With the standard Smart Nozzle Automation on the TruLaser 5030 fiber, the laser automatically checks the condition of the nozzle by recording a 3-D image and making an analysis as to whether the nozzle is still fit for production. If it is, production commences. If it’s not, the nozzle is unloaded and locked so it can’t be used until it’s replaced, and only then does production resume.
Keeping it consistent
All of this is great, but it’s for naught if power delivery isn’t consistent. The TruLaser 5030 fiber has the benefit of using a TruDisk laser source, which guarantees power consistency of ±1 percent over the life of the laser.
Typically, an average stability level is maintained over a limited duration (e.g., a single shift, or 8 hours) so long term, the operator must make compensations for fluctuations in laser power. Because of the TruDisk laser’s ability to measure power output in real time, consistency in power output is completely consistent. It can be reasonably argued that it’s this feature that is the most profound.
Overall, it’s reliability and longevity of a laser investment that customers should be able to expect. In addition to the snapshot of features laid out here for TruLaser 5030 fiber, there’s one variable to mention that, previously, a laser couldn’t control: the material. To address this issue, Trumpf introduced its Active Speed Control at Fabtech 2019. The technology allows the laser to proactively monitor the condition of a cut and respond before a problem arises.
Rather than waiting for a problem to arise and reacting after it’s already occurred, Active Speed Control can ensure that the problem doesn’t show itself at all. It controls for material surface issues, material content and quality issues, alloy variations, material thickness variations and more.
But it’s not just bad material that benefits. The technology can lower the feed rate when material quality is bad, but it can also increase the feed rate when the material quality is good. This means that with Active Speed Control customers typically see average feed rates 7 to 9 percent greater than the baseline.
For example, if a customer has an estimation to cut a part on a TruLaser 5030 fiber with Active Speed Control, the estimated time is for the base feed rate. If the part cuts at, say, 800 ipm, Active Speed Control for the average customer means an increase in feed rate to 872 ipm. That’s substantial, and it’s completely automatic.
A new, high-power fiber laser can have a huge impact on business. Make sure to consider whether the laser has the ability to cut not only quickly, but reliably, too.