Laser cutting is a technology that rapidly heats and melts the local part of the workpiece through the irradiation of the laser beam, and then vaporizes and cuts at a very high speed to form a slit. In the laser cutting process, the nozzle is a key component of the laser cutting machine, the main role is to control the laser beam on the surface of the workpiece focusing position, while accelerating the beam, so that the part of the irradiated area is melted and vaporized to form a slit. The geometry and size of the nozzle have an important effect on the cutting quality.
In the cutting process, the nozzle is the interaction medium between the laser beam and the workpiece, the nozzle will concentrate the laser beam to form a beam beam, the beam beam with a certain direction and speed (generally a certain size) irradiation to the surface of the workpiece to form a slit. This process is called laser cutting.
The shape of nozzle and the size of nozzle have great influence on the cutting quality. There are three main types of nozzles: parallel type, collected type and cone type.
If the nozzle is not selected properly, it will cause the flow rate of the gas to weaken, and the direction of the air flow will become unstable, which will affect the melting of the material during the cutting process and produce melting, and the cutting of thicker plates will even cause the inability to cut. In addition, the concentricity is not enough, the cutting section is easy to dissolve, the sharp corner is easy to melt, the laser application point is deviated from the actual, the finish is not enough and the melt is easy to attach, the cutting accuracy is not accurate, and the debugging of the difficult laser head is easy to damage.
When selecting the nozzle, it is necessary to consider cutting the thin plate (below 3mm) : the aperture range of the general nozzle is 0.8-15mm, and the flow rate of the small nozzle aperture is faster, and a good cross-section will be formed. If a larger nozzle aperture is selected, the flow rate is slow, and slag will be formed on the back of the plate section. When cutting medium thickness (3mm-10mm) range: generally choose 1.5mm-3.0mm aperture nozzle, although the smaller nozzle flow rate is faster, but insufficient flow will cause insufficient combustion, the larger nozzle flow rate is too slow will also form slag. When cutting thick plates (greater than 10mm) : 2.5mm to 5.0mm aperture is generally selected, and thick plates have higher requirements for gas flow, so a larger aperture is required.
In addition, there is a choice between a single nozzle and a double nozzle:
1.single-layer nozzle is generally used for stainless steel plate, aluminum plate, copper plate cutting;
2.double-layer nozzle is generally used for cutting carbon steel plate;
In short, the size of the nozzle aperture has a great impact on the cutting quality and perforation quality. Small hole nozzle cutting, small perforation, narrow slit, small gas diffusion area, corner place is not easy to hang slag, suitable for thin plate cutting; Thick plate cutting requires a large aperture nozzle to blow away the slag. However, when the aperture is too large, the probability of melting sparks splashing into the nozzle is high, and the protective lens is easy to bond the slag, and the life of the protective lens is shorter.
