Difficulties of High-power Laser Cutting Process and Solutions

With incomparable advantages such as large cutting range, fast cutting speed, and the ability to cut thicker plates, high-power laser cutting has been widely recognized by the market. However, as high-power cutting technology is still in the early stage of popularization, some operators are not very proficient in the techniques of high-power laser cutting. Senfeng Laser's high-power laser cutting engineers have summarized a series of solutions for poor quality high-power laser cutting through long-term testing and research, for reference by colleagues in all industries.

If the cutting effect is found to be poor, the following reasons should be investigated first:

1. All lenses in the laser head are not polluted and clean;

2. The water temperature of the water tank is normal, and the laser source has no condensation;

3. The cutting gas purity is excellent with smooth gas path, and there is no gas leakage.

Problem 1: Cutting surface has stripes

Possible Causes:

1. The nozzle is incorrectly selected: for example, the nozzle is too large;

2. The air pressure is set incorrectly: for example, and the air pressure is set too high, which will cause over burning and streaks;

3. the cutting speed is wrong, too slow or too fast cutting speed will also cause sufficient over burn.

Solution:

1. Replace the nozzle with a small diameter, such as for 16mm carbon steel bright surface cutting, you can choose high-speed nozzle D1.4mm; 20mm carbon steel bright surface can choose high-speed touch nozzle D1.6mm;

2. Reduce the cutting air pressure can improve the cutting quality of the surface;

3. Adjust the cutting speed and match the power with the cutting speed properly to achieve the effect shown in the right picture below.

Problem 2: There is slag on the bottom

Possible Causes:

1. The nozzle is too small and the cutting focus is not matched;

2. The air pressure is too small or too large, also the cutting speed is too fast;

3. The material of the metal sheet is poor, and the quality of the metal sheet is not good. It is difficult to remove the slag with a small nozzle.

Solution:

1. Replace the large-caliber nozzle and adjust the focusing focus to a suitable position;

2. Increase or decrease the air pressure until the air flow is appropriate;

3. Choose better metal sheet.

Problem 3: There are burrs on the bottom

Possible Causes:

1. The nozzle diameter is too small to meet the processing requirements;

2. the negative defocus does not match: the negative defocus should be increased, and the appropriate position should be adjusted

3. The air pressure is too small, which causes burrs on the bottom and cannot be fully cut.

Solution:

1. Choose large-caliber nozzles to increase air flow;

2. Increase negative defocus to make the cutting section reach the bottom position;

3. Increasing the air pressure to reduce the bottom burr.

How nozzle influence cutting quality:

When the center of the nozzle and the center of the laser are not on the same axis

1) it affects the cutting section. When the cutting gas is sprayed out, it will cause uneven air volume, which makes it easier for the cutting section to have melting stains on one side and not on the other side. Although it has little effect on the cutting of thin plates below 3mm.

2) It affects the quality of sharp corners. When cutting workpieces with sharp corners or small angles, local overmelting is likely to occur. It may not be possible to cut when it comes to thick plates.

Therefore, when the nozzle aperture is larger, the relative protection of the focusing lens is worse,  which makes the life of the lens shorter. The concentricity between the center of the nozzle and the laser is one of the most important factors that determines the cutting quality, especially when the workpiece is thicker. Therefore, the concentricity between the nozzle center and the laser must be adjusted to obtain a better cutting section.

Senfeng, with a professional team of engineer, continues to provide more solutions for laser cutting, welding, cleaning and cladding. Please contact us for more information.

Whatsapp:008613210546543

E-mail:senfeng@sfcnclaser.com