How can high-power lasers achieve scar-free, high-precision vertical cutting of thick plates?
High-power lasers enable scar-free vertical cutting of thick plates by optimising beam patterns, precisely controlling focal positions, intelligently adjusting cutting parameters, and utilising specialised auxiliary gas technology. The key lies in maintaining stable energy density and effective slag removal, ensuring a smooth, vertical cut across the entire cutting thickness.
How can scarless cutting be achieved through beam control?
High-power lasers achieve scarless cutting by optimising beam patterns, maintaining stable power output, and precisely controlling the focal point. A high-quality beam ensures uniform energy distribution, preventing localised overheating or insufficient energy, and resulting in a smooth and consistent cut surface.
Achieving a scarless incision is a complex undertaking that requires precise coordination of multiple technical aspects. Let’s delve into this process from the perspective of beam control.
Beam mode optimisation is fundamental. High-power lasers utilise a specialised fibre design to produce an output beam that approximates the fundamental mode (TEM00). This mode features an ideal Gaussian energy distribution, enabling focusing into a tiny spot and maintaining sufficient energy density during thick plate cutting. Our tests revealed that beams with a BPP value below 2.5 mm·mrad can control the kerf roughness to Ra ≤ 10 μm when cutting 30 mm carbon steel, which is significantly lower than the Ra ≥ 25 μm achieved by traditional cutting methods.
Power stability control is crucial. Our high-power lasers are equipped with advanced power systems and cooling devices, ensuring that power fluctuations do not exceed ±1.5% during extended cutting operations. This stability prevents uneven cut surfaces caused by power fluctuations. Our specialised process, developed for pressure vessel manufacturers, achieves consistent cut quality over 8 hours of continuous cutting, eliminating the wavy scars found in traditional cutting methods.
Focal point positioning accuracy determines energy transfer efficiency. High-power laser cutting heads are equipped with an autofocus system that monitors and adjusts the focal point’s position relative to the material surface in real time. When cutting a 30mm thick plate, a focal point position deviation of 0.1mm can lead to a significant decrease in cut quality. Our intelligent focal point control system maintains positional accuracy within ±0.05mm, ensuring optimal energy coupling throughout the entire cutting process.
Comparison of specific technical parameters:
Technical parameters | Traditional laser cutting | High-power precision cutting | Quality Improvement |
Beam quality (BPP) | 4-6 mm·mrad | 1.5-2.5 mm·mrad | 60% |
Power stability | ±3-5% | ±1-1.5% | 70% |
Focus control accuracy | ±0.15mm | ±0.05mm | 67% |
Cut roughness | Ra 20-35μm | Ra 8-15μm | 55% |
Real-time monitoring and feedback systems are crucial for quality assurance. We integrate multiple sensors into the cutting head to monitor cutting status in real-time and automatically adjust parameters. When an abnormal cut quality is detected, the system immediately corrects the cutting parameters to prevent defects from escalating. This system has increased the pass rate for thick plate cutting from 85% to 99.5%.
Adaptive optics technology further enhances beam control capabilities. Through deformable lens assemblies, the system can dynamically adjust the beam shape based on material thickness and cutting speed. When cutting workpieces with varying thickness, this technology automatically compensates for changes in energy density caused by thickness variations, ensuring consistent quality throughout the entire cutting path.
How does intelligent parameter control ensure the perpendicularity of the cut?
The intelligent parameter control system ensures cut perpendicularity through layered energy control, dynamic speed adjustment, and real-time focus compensation. The system treats thick plate cutting as a process of stacking multiple thin plates, matching optimal parameters for different depth regions to ensure energy balance throughout the thickness direction.
Cut perpendicularity is a core indicator for measuring the quality of thick plate cutting, directly affecting the workpiece’s performance and assembly accuracy. Intelligent parameter control uses multiple technical means to ensure near-perfect perpendicular cuts.
The core technology is a layered energy control strategy. The system divides the thick plate into multiple virtual layers along its thickness, calculating the optimal power, speed, and gas parameters for each layer. When cutting 25mm stainless steel, the upper layer operates at a higher speed and slightly lower power to prevent overheating. The middle layer maintains stable parameters to ensure cutting continuity, and the lower layer appropriately increases power to ensure complete penetration. This layered control achieves a cut perpendicularity of over 89.5°.
Dynamic speed adjustment addresses changes in actual processing. The system dynamically adjusts the cutting speed based on real-time monitoring of the cutting status. When slag discharge is impeded, the speed is appropriately reduced and the gas pressure increased; when the cut quality is good, the speed is automatically increased to the optimised level. Our statistics show that this dynamic adjustment improves cut perpendicularity consistency by 40%.
Focal point compensation technology addresses the thermal lensing effect. During the cutting of thick plates, heat accumulation at the top of the material alters the energy distribution at the bottom, resulting in a taper in the cut. Our intelligent system compensates for this by dynamically adjusting the focal point position through real-time calculation of the thermal impact. This technology reduces the taper of the cut in 30mm carbon steel from the traditional 0.5-1° to 0.1-0.3°.
Key technologies for verticality control:
Control technology | Working principle | Improvement effect |
Layered energy control | Optimize parameters by depth partitioning | Verticality increased to 89.5°+ |
Dynamic speed adjustment | Real-time response to cutting status | Consistency improved by 40% |
Focus compensation | Counteracting thermal lensing effect | Taper reduced by 70% |
Gas flow field optimization | Maintain stable auxiliary airflow | Slag residue reduced by 90% |
Optimized gas flow field ensures vertical cutting. In thick plate cutting, the Auxiliary gas not only serves for combustion and cooling but also plays a crucial role in removing molten slag. Through computational fluid dynamics analysis, we developed a special nozzle design that maintains stable gas velocity and pressure throughout the entire cutting depth. This system can still guarantee the complete removal of bottom slag when cutting 40mm carbon steel.
The process parameter database supports intelligent decision-making. The system has accumulated a large number of verified cutting parameters, encompassing various combinations of materials, thicknesses, and qualities. Operators only need to input basic requirements, and the system can automatically generate optimised parameters. Even novice operators can achieve professional cutting results quickly and efficiently.
Machine learning algorithms continuously optimise cutting quality. The system records the parameters and results of each cut and uses algorithms to analyse and find the optimal parameter combination. Over time, the system becomes increasingly “intelligent,” and the cutting quality continues to improve. One of our systems, which has been running for two years, has automatically generated parameters that are 15% more effective than the initial manually optimised parameters.
How can auxiliary gas technology promote the effective removal of molten slag?
Assist gas promotes the effective removal of molten slag by providing sufficient kinetic energy and a suitable chemical environment. High-power laser cutting utilises a specialised nozzle design and precise gas pressure control to create a stable airflow field within the cut, ensuring the complete removal of molten metal and achieving a clean cut surface.
The effectiveness of slag removal directly affects the cut quality and perpendicularity. Assisted gas technology plays an irreplaceable role in addressing this problem, and its technical implications are far more complex than they initially appear.
The innovative nozzle design represents a fundamental breakthrough. Traditional nozzles tend to generate turbulence when cutting thick plates, leading to energy loss in the airflow. Our developed convergent-divergent nozzle, through a special internal cavity design, creates a uniform, high-speed airflow at the outlet. Test data show that this design improves gas kinetic energy utilisation by 35% and maintains a bottom airflow velocity of 1.5 times the speed of sound when cutting 25mm material.
Precise pressure control ensures process stability. Cutting thick plates requires higher gas pressure, but excessive pressure can cause unnecessary cooling. Our intelligent air pressure control system dynamically adjusts the pressure based on material thickness and cutting speed, providing optimal airflow conditions for different cutting areas. This system improves air pressure control accuracy to ±0.2 bar, ensuring stable slag discharge.
Gas selection strategy influences the chemical properties of the cut. For cutting thick carbon steel plates, we use oxygen as the assist gas, utilising the oxidation reaction to provide additional heat. For stainless steel and aluminium alloys, we use nitrogen or argon to prevent oxidation. Our developed intelligent gas switching system can automatically switch between different gas types on the same workpiece according to varying material requirements.
Gas technical parameter optimisation:
Material type | Recommended gas | Pressure range | Nozzle type | Effect |
carbon steel | oxygen | 1.5-2.5 bar | Double-layer nozzle | No slag, slight oxidation |
Stainless steel | Nitrogen | 2.0-3.0 bar | Single-layer nozzle | Oxide-free silver cut |
aluminum alloy | Nitrogen | 2.5-3.5 bar | Special diffusion nozzle | Burr-free, bright white cut |
copper alloy | Nitrogen/Argon | 1.8-2.8 bar | Anti-reflective nozzles | No zinc volatilization, smooth cut |
Uniform airflow ensures cleanliness across the entire thickness. The challenge in cutting thick plates lies in maintaining adequate airflow throughout the whole cut depth. Through precise nozzle position control and optimised aerodynamics, we establish a stable pressure gradient within the cut, ensuring sufficient slag removal from top to bottom. This technology reduces slag residue in 40mm carbon steel cutting from 15% using conventional methods to below 1%.
Temperature monitoring and gas parameter linkage enhance reliability. We integrate an infrared temperature sensor in the cutting area to monitor the temperature distribution of the cut in real time. When an abnormal temperature is detected, the system automatically adjusts the gas parameters to prevent slag adhesion due to insufficient temperature or overheating due to excessive temperature.
Energy-saving gas circulation systems reduce operating costs. High-power, thick-plate cutting consumes a large amount of gas. Our developed gas recovery and circulation system can recover and reuse a portion of the auxiliary gas, thereby reducing waste and increasing efficiency. This system saves customers 30% on gas costs while maintaining the same cutting quality.
in conclusion
High-power lasers, through advanced beam control, intelligent parameter adjustment, optimised auxiliary gas technology, and comprehensive real-time monitoring, have achieved scar-free, high-precision vertical cutting of thick plates. This technological breakthrough not only addresses a long-standing pain point in the manufacturing industry but also opens up new possibilities for high-end equipment manufacturing, continually driving the advancement of industrial processing technology.
