The effect of nozzle for fiber laser cutting machine 
1. The cutting section is not flat. If the nozzle is not concentric with the laser, When the auxiliary gas is ejected, the air flow is not uniform, and it is prone to melt stains on one side of the cut section. It has little effect on thin plates below 3mm, but for plates above 3mm, the effect is more serious, and it may even cause failure to cut.
2. It cannot be cut at a small angle. When cutting workpieces with sharp or small angles, uneven gas ejection may cause partial overmelting of the workpiece.
3. Unstable perforation. The heat is uneven during perforation, and the perforation time is not easy to control. When perforating thick plates, it may cause overmelting due to poor time control, and the penetration conditions are not easy to grasp, which has little effect on the perforation of thin plates.
The concentricity between the center of the nozzle and the laser is one of the important factors for cutting quality. The thicker the cut workpiece, the greater its influence. Therefore, the concentricity between the nozzle center and the laser must be adjusted to ensure the cutting quality. At the same time, for cutting metal of different thickness, we need to choose nozzle apertures of different sizes.
If the nozzle is deformed or there is residue on the nozzle, it will affect the cutting quality to a certain extent. Therefore, the nozzles should be cleaned regularly.