It wasn’t long ago that a job shop working with significantly different thicknesses of materials required two completely different lasers: If you wanted to cut thin materials, a fiber laser was the machine of choice. But if thicker material was on the cut list, a CO2 laser had to be called in for the job.
Since the advent of BrightLine fiber, developed by Trumpf Inc., one machine using special optics with flow-optimized nozzles, is able to provide the performance advantages of fiber while maintaining the quality and process reliability that a CO2 would provide when thicker materials are brought to the cutting table.
A machine using BrightLine technology comes equipped with two fiber optic cables, which allows operators to switch between beam modes within nanoseconds, giving greater flexibility when switching from piercing to cutting and when working with a variety of material thicknesses.
Brett Thompson, sales engineer for Trumpf, says that with BrightLine, the company is able to offer a very small beam for thin materials and a large beam for thicker materials. Material types vary as well and include steel, stainless steel, copper and aluminum.
“We can operate on the two extremes – the beam diameter can range from really small to very large in spot size,” he says. “That gives us the performance advantage of fiber while still maintaining the quality and process reliability of CO2 when you get into the thicker range.”
When using BrightLine fiber, operators can use different pierce processes depending on whether they’re using oxygen or nitrogen. When cutting stainless steel, for example, the laser nozzle will be different than what would be used while working with oxygen on carbon steel.
“Our pierce process is staged where we change the beam configurations,” Thompson explains, adding that Trumpf refers to the capability as piercing control. “When you get through the material, the hole widens and that keeps the material from bulging on the surface – you don’t have any buildup of material.”
Thompson says that piercing control technology actually takes into account how much light is being reflected back during the piercing of the material. Once the light being reflected indicates that the piercing process has been completed, that information is relayed back to BrightLine fiber, which will then change the beam configuration so that it can immediately switch from piercing to cutting.
“We’re going from the ideal scenario for piercing to the ideal scenario for cutting,” Thompson says.
The ability to quickly adjust beam thickness allows a laser equipped with BrightLine to cut through a variety of different materials from thin to thick.
At Fabtech 2017, Trumpf revealed its 10-kW laser, which will be available for purchase later this year. Until that time, the most productive machine Trumpf produces at the moment is the TruLaser 5030, which is offered with laser capacities of 6 kW and 8 kW.
“It’s the fastest machine we have with the most laser power and the most features,” Thompson says. “It’s going to cut faster, have more capabilities and more automation options than some of our other equipment.”
The BrightLine piercing technology Trumpf uses on lasers like the TruLaser 5030 allows it to efficiently work with thick metal without causing buildup of materials.
The drive system in the TruLaser 5030 is the most rapid in Trumpf’s lineup with extreme accelerations. When opting for the 8-kW machine, operators get greater thickness capacity for fusion cutting or nitrogen cutting for steel.
Despite the TruLaser 5030’s proven productivity, utilizing BrightLine fiber in a machine like this has many advantages. For example, when working with material thickness of around 1/4 in., the kerf is small, which means it won’t face the same difficulty traditional fiber lasers experience with moving the molten material through the kerf.
“At some point you lose the benefit of the fiber,” Thompson says of cutting thicker materials with fiber lasers. “You don’t cut as fast and the quality of the cut begins to suffer. So, with BrightLine fiber, you get a much bigger beam so those edge condition concerns go away.”
BrightLine’s solutions allow fiber users to process a wide range of material types and thicknesses.
In the Trumpf video shown on page 23, a TruLaser 5030 making a standard cut on mild steel shows the operator having to hammer on the finished part to break it loose from the skeleton. However, the same machine using BrightLine shows the operator easily removing the part with no hammering required because the cut quality is much cleaner.
The flexibility the BrightLine technology brings to metalworkers is a huge benefit, especially for those who want to clear out a couple of old CO2 lasers and replace them with a fiber laser equipped with BrightLine. Thompson says he’s witnessed this with more than one OEM that wants the flexibility to work with many different material thicknesses.
“The normal customer is the job shop,” Thompson says, “largely because it’s the machine that’s going to be able to tackle the largest variety of processes.”
Nozzles and lenses
Another technology that has improved the TruLaser 5030, and which Thompson refers to as the “most impactful,” includes what Trumpf has christened the Highspeed and Highspeed Eco nozzles. This technology offers increased throughput and reduced nitrogen consumption for solid-state lasers.
In a default nozzle configuration, the distance between the nozzle and the sheet metal leads to a loss of cutting gas. Operators must use high gas pressure to push slag out of the kerf. However, the Highspeed and Highspeed Eco nozzles use a sleeve that creates a seal on the cutting surface. This prevents gas from escaping.
It’s a patented technology that has been used for material thicknesses that haven’t always been viewed as appropriate for nitrogen cutting, Thompson points to 1/4-in. or 3/8-in.-thick materials as examples. Depending on sheet thickness, throughput can increase by up to 100 percent with the Highspeed and Highspeed Eco nozzles. Furthermore, gas consumption is reduced by 70 percent.
“The sleeve can also rise with contours,” Thompson explains of uneven material, “so we don’t run into issues with process reliability. The improvements in edge quality and speed, while using considerably less gas, have made Highspeed and Highspeed Eco an extremely popular technology.”
Finally, Thompson adds that the focus of the TruLaser 5030 has been on automation so that machines work more reliably. For example, in solid-state laser machines, the lens is shielded by protective glass, which will keep the smoke residue, spatter and steam away from the lenses.
When the protective glass becomes contaminated, cut quality is affected. Therefore, Trumpf designed a monitoring system so that if, for example, it’s 2 a.m. and the machine is operating but there is nobody around to see that the glass is contaminated, the monitoring system will interrupt the work, halting it until the issue is resolved.
“The changes on the TruLaser 5030 are really geared toward automation and improved reliability,” Thompson says. “And the BrightLine and Highspeed and Highspeed Eco technologies further catapult the machine toward those goals.”