The fiber laser nozzle can assist the gas to be ejected quickly, which can effectively prevent the melting stains and other debris from rebounding, thereby protecting the focusing lens. At the same time, it can control the area and size of gas diffusion, which will affect the cutting quality of the laser cutting machine. At the same time, the aperture size of the fiber laser nozzle will vary according to the thickness of the cutting material.
In the laser cutting process, the fiber laser nozzle collects the capacitance signal and transmits it to the signal processor through the ceramic ring, so as to maintain the distance between the laser head and the workpiece during the cutting process of the laser cutting machine, and guide the gas to pass through the workpiece smoothly. And then a high pressure is formed at the nozzle exit to speed up the cutting speed, take away the slag, and protect the lens inside the laser head.
Generally, fiber laser nozzles are divided into single layer and double layer types. Single layer fiber laser nozzles are used for melting and cutting, and the nitrogen is used as auxiliary gas. It is usually used for cutting stainless steel, aluminum alloy, brass, etc.; double layer fiber laser nozzles are generally used for oxidative cutting, that is, oxygen is used as auxiliary gas. It is usually used for cutting carbon steel.
The diameter of the fiber laser nozzle determines the shape of the gas flow, the gas diffusion area and the flow rate of gas entering the cut, and affects the removal of the melt and the stability of the cutting. When the gas flow entering the cut is large and fast, and the position of the workpiece in the gas flow is appropriate, the spray has higher ability to remove the melt. The user chooses the size of the fiber laser nozzle according to the laser power used and the thickness of the cut metal plate. Theoretically, the thicker the plate, the larger the fiber laser nozzle should be used. The greater the set pressure of the proportional valve, the greater the flow rate, which can ensure the pressure to achieve the effect of cutting the front section.
(1) When cutting thin plates (below 3mm), a fiber laser nozzle with Φ1mm aperture will be too thin, while a fiber laser nozzle with Φ1.5mm aperture will be too thick, and the corners will be more prone to melting stains.
(2) When cutting thick plates (above 3mm), the fiber laser nozzle with Φ1mm aperture is not stable when used. Because the cutting power is high at this time, the relative heat dissipation time is longer, and the relative cutting time also increases. The gas diffusion area of the nozzle with Φ1mm aperture is small, so it is not stable, but it can basically be used. However, the nozzle with a aperture of Φ1.5mm has a large gas diffusion area and a slower gas flow rate, so it is relatively stable during cutting.
(3) When cutting plates over 10mm, currently fiber laser nozzles with a aperture of 2mm or above are generally selected. However, the larger the aperture of the fiber laser nozzle, the smaller the protective effect on the focusing lens. Therefore, a reasonable choice of the size of the aperture of fiber laser nozzle can ensure more effective production.