(1) the principle of laser cutting
Laser cutting is the use of the focusing of high power density laser beam workpiece, so that the irradiated material rapidly melting, vaporization, ablation, or to achieve ignition, with the beam coaxial high-speed airflow to blow the molten material, in order to achieve the cut workpiece opened. Laser cutting belong to one of the thermal cutting. The principle of laser cutting are shown below.
(2) the classification of laser cutting
Laser cutting can be divided into the laser vaporization, laser melt cutting, laser oxygen cutting and laser scribing and control of breaking four categories.
1) laser vaporization
Use of high energy density laser beam to heat the workpiece, the temperature rose rapidly to reach the boiling point of the material in a very short period of time, the material begins to vaporize, forming steam. These vapors emitted speed, while the vapor emitted, the material on the formation of the incision. Heat of vaporization of the material in general, so requires a lot of power and power density of laser vaporization.
Laser vaporization are used for cutting thin metal material and non-metallic materials (such as paper, cloth, wood, plastic and rubber, etc.).
2) laser melt cutting
Laser melt cutting using laser heating to the melting of metallic materials, and then through the injection nozzle beam coaxial non-oxidizing gases (Ar, He, N, etc.) rely on the strong pressure of the gas so that liquid metal discharge, the formation of the incision. Laser melt cutting does not require the metal completely vaporized, the energy required for vaporization cutting 1/10 only.
Laser melt cutting is mainly used for the easy oxidation of the material or activity of metal cutting, such as stainless steel, titanium, aluminum and its alloys.
3) Laser oxygen cutting
Laser oxygen cutting principle is similar to oxyacetylene cutting. It is as a warm-up heat source with a laser as a cutting gas, oxygen and other reactive gases. Blowing out of gas on the one hand and cutting metal effect, the occurrence of the oxidation reaction and emit a large number of oxidation heat; other molten oxides and melt blowing from the reaction zone, the formation of the incision in the metal. Generated a lot of heat due to the cutting of the oxidation process, the laser oxygen cutting the energy required to melt just cutting 1/2, while the cutting speed is much larger than the laser vaporization and melting cutting.
Laser oxygen cutting is mainly used for carbon steel, titanium steel and heat-treated steel, easily oxidized metallic materials.
4) laser scribing and control fracture
The laser scribing is the use of high energy density laser scanning the surface of brittle materials, the material to heat the evaporation of a small slot, and then apply some pressure, brittle materials will split along the small groove. The laser scribing laser is generally Q-switched lasers and CO2 lasers.
Control fracture using laser groove produced by the steep temperature distribution, local thermal stresses in brittle materials, the material along the small groove is disconnected.
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