Once upon a time, cutting thick plate was a slow and difficult process. Fiber lasers had a reputation for being the fastest cutting machine on the shop floor – until they were confronted with a piece of heavy material, that is. With the advent of high-power fiber lasers, however, things have changed. Everyone from a small job shop to a large OEM can get involved in heavier, thicker applications in a growing list of industries that includes construction, shipbuilding, mining, energy, heavy machinery and beyond.
“Many industries have moved away from plasma and flame cutting and toward laser cutting due to improvements in cutting thick plate,” says Hank White, laser product manager, Mazak Optonics Corp. “Many of these customers range from shipyards to steel supply centers where thick plate jobs are more prevalent.”
High-level benefits
The advantages of cutting thick plate with a laser versus plasma or flame cutting were always apparent, but until the higher power levels, they were often out of reach. Today, the benefits of cutting thick plate with a laser include smooth edges, higher cutting speeds and reduced thermal distortion, which leads to further benefits like improved production efficiency, higher product quality and a range of related cost savings.
One of the biggest benefits of using laser cutting for thick plate, however, is the level of precision. Laser cutting minimizes mechanical stress and deformation, even on thick plate. This results in parts with smooth, high-quality edges that require less post-processing, leading to minimal waste, higher quality outputs and, ultimately, cost savings.
Additionally, the speeds at which laser cutting machines operate can significantly boost production efficiency, saving both time and resources.
The thermal challenges involved with cutting thick plate occur due to the difficulty managing heat distribution across the thicker sections of the material. Thick plate is typically uneven in places, which can affect its mechanical properties. When it is not properly controlled, the heat can lead to warping and can even damage the material. To mitigate this, it is important to properly adjust the laser power settings and focus during the cutting process.
“The biggest challenge with thick plate cutting is material quality and diversity,” White says. “Many factors affect cutting quality, and fiber lasers are highly tuned to work well in specific materials. Material that is over 1 in. thick is not a consistent mill quality or material content. It varies from different mills or even lot numbers. Any deviation in material content or surface quality drastically changes the cutting characteristics. Even an experienced operator can have difficulty adapting to these changes and maintaining good laser cutting.”
Tuning the process
The fact that material deviations can be better controlled today is thanks in part to modern laser cutting machines equipped with advanced controls that allow for real-time adjustments. Today’s controls are designed to optimize settings to fine-tune the cutting process, be it for thin or thick plate, with an overarching goal to maintain consistent edge quality and reduce thermal issues. These settings, which are key to successfully cutting thick plate, control the laser power, focus position and cutting speed to ensure that the laser beam penetrates the material effectively to maintain quality.
Mazak’s approach to cutting thick plate is found in its Optiplex HP 2-D laser cutting system, which is available in three power options – 15 kW, 20 kW and 30 kW – and two machine sizes – 4220 and 3015. The system is equipped with advanced technology that allows processing of material up to 2 in. thick.
One of these advanced technologies is the company’s new Grand Cut nozzle head technology, which allows for an increased focal length range and programmable spot size, helping to stretch the cutting range beyond the traditional 1-in. limit in mild steel to double that. It ensures optimal settings for each material type for consistent and high-quality processing of thick plate.
“Grand Cut technology effectively addresses issues with material quality and consistency,” White says. “By using a new nozzle design with specific gas flow characteristics, users can now easily cut a wide range of materials with little to no adjustment. This opens the door for users to process thick plate both effectively and reliably. Cutting up to 2-in. mild steel is now a reality, even for the newest operator.”
At the laser source, Mazak has also given users advanced technology that improves thick plate cutting. The SmoothCut fiber laser oscillator, where the beam is created, achieves the utmost in reliable beam quality. Across a range of materials and thicknesses, users can expect optimized performance for thick plate cutting.
“Together, through better, more reliable beam quality with SmoothCut and improved flow dynamics with Grand Cut, the laser can achieve higher cut quality and increased thick plate cutting reliability,” White explains.
Machine mechanics
Without today’s higher power lasers and advanced laser technologies, thick plate would probably still be processed the old-school way with plasma machines and flame cutting methods. But there is more to modern processing than the laser itself.
In addition to high-speed and high-quality laser processing, the Optiplex HP system also integrates design features aimed at improving productivity and accessibility. Large, wide-opening sliding doors on the front and sides of the machine provide unobstructed access to the cutting table. In an era of persistent labor shortages, this makes material loading and unloading faster and more efficient.
A rotating CNC control panel also gives operators the option to work at the front or side of the machine. The screen also tilts, offering a comfortable operating position for all users.
To keep an eye on the cutting process and the nozzle in particular, Mazak integrated a camera within the laser that is mounted next to the nozzle holder to check the center position of the nozzle. The nozzle center can be easily adjusted by turning the dial while viewing the operation screen. Nozzle centering is crucial for a consistent gas flow around the beam. If the centering is incorrect, the cut can be drossy or even result in a lost cut on one side of the processed part.
“The option to include automatic nozzle alignment and monitoring reduces operator intervention during setup,” White says. “This also reduces the potential for cutting losses through real-time monitoring of the cutting process.”
To reduce waste, automatic detection of the cutting area for nesting is available. With Camera Network Nesting, a camera inside the machine detects the remnant material and automatically identifies the best nesting pattern. It reduces operator intervention and creates an easier setup, saving time. The operator can easily cut a single part without having to go back to a programmer for help.
With rapid advancements in laser technology, laser cutting for thick plate is evolving. Key future trends include even higher power lasers and continued integration of AI for real-time monitoring, predictive maintenance and adaptive cutting parameter adjustments.
Cutting thick plate with a laser is a viable option for precision and efficiency in the shop. Understanding how the technology works and optimizing cutting parameters will help overcome many of the challenges associated with laser cutting thick materials. Users will find clean edges, enhanced efficiency and cost savings. Industries can meet the demands for high-quality thick metal parts with less waste and faster turnaround times.
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