The physical process of cutting of various materials from the laser. The laser cutting can be divided into the following six categories;

1 vaporization

Vaporization, refers to removal of the material being processed is mainly carried out by the material vaporized mode. On vaporization cutting process, the surface of the workpiece in the focused laser beam under the action of temperature;, rose quickly to the vaporization temperature, material vaporization, high pressure steam is formed by the supersonic jets. At the same time, the formation of "holes" in the zone of action of laser, laser beam in the cavity and the material reflection of laser absorption Feng quickly improve.

In the process of high pressure steam jet in cutting slot, the melt is also from the slit is blown away, until the cutting workpiece. On vaporization depends mainly on the material vaporized manner, so the power density required is very high, the general should achieve was 10 per sq cm above the eight kelly. Vaporization is laser cutting some low ignition point material (such as wood, carbon and certain plastic) and refractory materials (such as ceramics and so on) often mining method. Using pulse laser cutting material also by vaporization.

2 fusion cutting

In the laser cutting process, if you add a coaxial with the laser beam auxiliary blowing system, so that the cutting process of the melt is not removed by vaporization of material itself, and mainly depend on the role of high speed auxiliary gas flow, the melt is continuously from the slit blow away, cutting process such as fusion cutting.

In the metal cutting process, the temperature of the workpiece is no longer need to be heated to the vaporization temperature, so the laser power density required can be greatly reduced. The latent heat of melting and vaporization of the material than the required laser power, fusion cutting only cutting method for vaporization of the 1 / 10.

The 3 reaction fusion cutting

In the fusion cutting. If the air is not just blow away the melt within the crevice cut, but also can change the thermal reaction and the workpiece, the cutting process to increase the other heat source, such a cut called reaction fusion cutting. Gas usually can react with the workpiece is mixed gas oxygen or oxygen-containing hugh.

When the surface temperature of the workpiece in achieving the ignition temperature, combustion occurs strong exothermic reaction, which can greatly improve the ability of laser cutting. For low carbon steel and stainless steel, provide combustion exothermic reaction energy is 60%. For the titanium active metal, burned to provide energy is about 90%.

Therefore, the reaction fusion cutting and laser vaporization cutting, as compared with the power density of the laser fusion cutting, lower the required, 1 / 20 cut is only vaporization, melting the cutting of the 1/2. However, in the reaction fusion cutting, in the combustion reaction can make the material surface chemical changes, which will affect the performance of the workpiece.

For example. In the cutting edge of titanium oxide layer is formed very hard, the oxide layer is easily broken, very serious impact, except for low carbon steel, formed on the cut surface with a thin layer of modified oxidized layer. Other effects is very small. Moreover, this oxide slag. Good fluidity. Unlike the metal slag that clings to the base metal. For stainless steel. The generation of oxide mainly composed of high melting point materials.

4 thermal stress cutting

Brittle materials in the heating laser beam. Its surface is easy to generate larger stress. Thus can be neat, Xun oil by laser heating stress cause fracture. The cutting process such as laser thermal stress cutting. The mechanism of heat stress cutting: a region of brittle material of laser beam heating. The obvious temperature gradient.

The surface temperature of the workpiece to swell and high workpiece inner low temperature to hinder the expansion, the tensile stress in the workpiece surface. The inner produce radial compressive stress. When these two kinds of stress exceeds the ultimate strength of the workpiece itself when the fracture. Will appear crack on the surface of the workpiece. For the development of the crack.

The workpiece along the crack opening. Speed - thermal stress cutting unit for the m/s magnitude. This cutting method is suitable for cutting glass, ceramics and other materials. The experimental surface thermal stress cutting glass effect is very good. The cutting speed, cutting quality and precision of depression is high. Laser thermal stress cutting required is very small. The power is too high will cause the workpiece surface melting. And destroy the trimming quality.

5 laser scribing

This method is mainly used for: semiconductor material; in the semiconductor material of workpiece surface draw - a shallow trench using laser beam power density is very high, because this trench weakened the binding force of semiconductor materials. Method can approach mastery machinery or vibration of the fracture. The quality of laser scribing by surface debris and to measure the size of the heat affected zone.

6 cold cutting

This is a new processing method, is put forward with the advent of high power excimer lasers in recent years and the ultraviolet band. Its basic principle: the combination of ultraviolet photon energy with many organic materials can be similar, bond with high-energy photons that hit the organic material and the rupture. So as to achieve the purpose of cutting. This new technique has wide application prospect, especially the application in the electronics industry will be extensive.