As the economy continues to develop, people's pursuit of a higher quality of life has grown. Consequently, the use of stainless steel in daily life has increased significantly. Nowadays, the laser cutting stainless steel thick plate process is becoming more and more mature, and will gradually replace the traditional cutting process. To cut high quality thick plate stainless steel, you need to fully understand the elements of the cutting process.
Nozzle selection
The size of the nozzle diameter determines the shape of the gas flow into the kerf, the gas diffusion area, and the gas flow rate. These factors affect the removal of molten material and the stability of the cut. Into the mouth of the gas flow rate is large, fast, the workpiece in the gas flow in the right position, the ability to remove the melt jet the stronger. To achieve a normal section effect, monitor gas pressure while adjusting for thicker stainless steel. Select larger nozzle sizes, and set the proportional valve to increase the flow rate, ensuring consistent pressure.
Gas selection
Stainless steel laser cutting process often use a variety of auxiliary gases, such as oxygen, nitrogen, air, etc., the use of different types of gases, the effect of cutting section is different. Oxygen produces a black section, air creates a yellowish hue, and nitrogen preserves the original color of stainless steel by preventing oxidation. Stainless steel cutting with nitrogen as the preferred auxiliary gas.
[Oxygen] Advantages: high cutting speed, can cut thick sheet material purity recommendation: ≥99.999%
Nitrogen] Advantages: to avoid the oxidation of the cutting edge, so the workpiece does not need to be re-processed Purity: ≥ 99.995%.
Focus position
In order to ensure that the cutting effect, and to protect the nozzle from damage, before cutting and processing also need to do coaxial test to ensure that the nozzle and laser output beam coaxial. Test method: stick the transparent tape paper to the nozzle outlet end face, adjust the laser output power for punching, observe the transparent tape paper whether there is a center hole and the location of the center hole, synchronous adjustment of the mirror cavity handle on the adjusting screw, until the laser in the transparent tape on the holes punched out of the paper and the center of the nozzle overlap.
The focus varies depending on the thickness, material, and quality being cut. Adjust the focus accordingly when cutting different materials and thicknesses to achieve optimal results.Before cutting, measure the actual zero focus and use it as a benchmark. This allows for testing and analyzing the cutting process parameters, with stainless steel cutting primarily using negative defocus as the process direction.
Fourth, the laser frequency adjustment, as well as the duty cycle on the impact of cutting quality
Frequency changes on the impact of stainless steel plate cutting:
Frequency from 500-200Hz range decreases, the effect of cutting section becomes delicate, delamination slowly improve. When the frequency is set to 100Hz, it is impossible to cut and anti-blue light. Find out the optimum frequency range by changing the frequency. To ensure the best cutting section, match the number of pulses perfectly with the single pulse energy.
The effect of duty cycle change on the cutting of thick stainless steel plate:
Duty cycle 53% is the critical value, continue to reduce the duty cycle, the lower surface of the uncut traces, the duty cycle increased to 60%, the section becomes rough, delamination is obvious, the cutting surface yellowing.
Summarize
To achieve precision work, it is essential to test and analyze factors such as nozzle height, machine movement parameters, acceleration, running speed, and material impact on cutting results. Professionals in laser process debugging and other aspiring experts must actively contribute to enhancing the laser cutting process. As laser cutting capacities reach 150 mm or higher, the industry's applications will expand even further.
