Views: 2 Author: Maichuang Laser Publish Time: 2021-04-14 Origin: Site
Ⅰ Vaporized cutting
means that the removal of the processed material is mainly carried out by vaporizing the material.
In the process of vaporization and cutting, under the action of the focused laser beam on the surface of the workpiece, the temperature rapidly rises to the vaporization temperature, the material is vaporized in a large amount, and the high pressure vapor formed is ejected outward at supersonic speed. At the same time, a "hole" is formed in the laser action area, and the laser beam is reflected multiple times in the hole to rapidly increase the absorption of laser light by the material.
In the process of high-pressure steam jetting at high speed, the molten material in the slit is blown away from the slit at the same time until the workpiece is cut off. The internal vaporization cutting is mainly carried out by vaporizing the material, so the required power density is very high, generally it should be more than 10 octave watts per square centimeter.
Vaporized cutting is a method of laser cutting some low-ignition-point materials (such as wood, carbon and certain plastics) and refractory materials (such as ceramics). When cutting materials with pulsed lasers, vaporized cutting methods are often used.
ⅡReactive melting cutting
In melting and cutting. If the auxiliary airflow not only blows away the molten material in the slit, but also can react with the workpiece to heat up, so that the cutting process adds another heat source, such cutting is called reactive melting cutting. Generally, the gas that can react with the workpiece is oxygen or a mixed gas containing oxygen.
When the surface temperature of the workpiece reaches the ignition temperature, a strong combustion exothermic reaction will occur, which can greatly improve the ability of laser cutting. For mild steel and stainless steel, the energy provided by the combustion exothermic reaction is 60%. For active metals such as titanium, the energy provided by combustion is about 90%.
Therefore, compared with laser vaporization cutting and general melting cutting, reactive melting cutting requires a lower laser power density, which is only 1/20 of vaporization cutting and 1/2 of melting cutting. However, in reactive melting cutting, the internal combustion reaction will cause some chemical changes on the surface of the material, which will affect the performance of the workpiece.
Ⅲ Melt cutting
In the laser cutting process, if an auxiliary blowing system coaxial with the laser beam is added, the removal of the molten material during the cutting process does not rely solely on the vaporization of the material itself, but mainly depends on the blowing action of the high-speed auxiliary airflow to remove the molten material. Continuously blowing away from the slit, this cutting process is called melting cutting.
In the melting and cutting process, the temperature of the workpiece no longer needs to be heated above the vaporization temperature, so the required laser power density can be greatly reduced. According to the latent heat ratio of material melting and vaporization, the laser power required for melting and cutting is only 1/10 of the vaporization cutting method.
Ⅳ laser scribing
This method is mainly used for: semiconductor materials; using a laser beam with a high power density to draw shallow grooves on the surface of the semiconductor material workpiece, because this groove weakens the bonding force of the semiconductor material. Ketongda Machinery Method or vibration method to make it break. The quality of laser scribing is measured by the size of surface debris and heat-affected zone.
This is a new type of processing method, which was proposed with the emergence of high-power excimer lasers in the ultraviolet band in recent years. Its basic principle: The energy of ultraviolet photons is similar to the binding energy of many organic materials, and such high-energy photons are used to hit the binding bonds of organic materials and break them. So as to achieve the purpose of cutting. This new technology has broad application prospects, especially in the electronics industry.
Ⅵ Thermal stress cutting
Brittle materials are heated by a laser beam. The surface is prone to large stress. It can be neatly and quickly caused by the stress points heated by the laser. This cutting process is called laser thermal stress cutting. The mechanism of thermal stress cutting is: the laser beam heats a certain area of the brittle material to produce an obvious temperature gradient.
The higher the surface temperature of the workpiece, the expansion will occur. The lower temperature of the inner layer of the workpiece will hinder the expansion, resulting in tensile stress on the surface of the workpiece. The inner layer produces radial compression stress. When these two stresses exceed the fracture ultimate strength of the workpiece itself. Cracks will appear on the workpiece. Make the workpiece break along the crack. The speed of thermal stress cutting-strand is on the order of m/s. This cutting method is suitable for cutting glass, ceramics and other materials.
Summary: Laser cutting machine is a cutting technology that uses laser characteristics and lens focus to concentrate energy to melt or vaporize the surface of the material. It can achieve the advantages of good cutting quality, fast speed, more cutting materials, high efficiency, etc.