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Laser cutting machine cutting common engineering materials

Release time:2021-01-21 source:Dongguan Xinke Laser Technology Co., Ltd

1、 Principle of laser:



The full English name of laser is light amplification by stimulated emission of radiation (laser). It was introduced in 1960. It is a kind of light strengthened by stimulating radiation.

Scientists in the tube with light or current energy to impact some crystals or atoms easily excited substances, so that the atomic electrons to excited high-energy state, when these electrons want to return to a calm low-energy state, the atoms will emit photons, in order to release excess energy; and then, these emitted photons will impact other atoms, exciting more protons Photons produce photons, which trigger a series of "chain reactions" and all move in the same direction, forming intense and concentrated light in a certain direction. Strong laser can even be used for laser cutting, cutting steel plate!

2、 Laser cutting machine cutting common engineering materials

1. Laser cutting of metal materials.

Although almost all metal materials have high reflectivity to infrared wave energy at room temperature, CO2 laser emitting 10.6um beam in far infrared band has been successfully applied to laser cutting of many metals. The initial absorptivity of metal to 10.6um laser beam is only 0.5% ~ 10%. However, when the focused laser beam with power density more than 106W / cm2 irradiates the metal surface, the surface can start to melt quickly in microseconds. The absorptivity of most metals in the molten state increases sharply, generally by 60% ~ 80%.

2. Laser cutting of nonmetallic materials.

The 10.6um CO2 laser beam is easily absorbed by non-metallic materials. The poor thermal conductivity and low evaporation temperature make the absorbed beam almost enter into the material and vaporize instantly at the spot, forming initial holes and entering into a virtuous cycle of the cutting process.

3、 The main technology of laser cutting machine

1. Vaporization cutting.

Under the heating of high power density laser beam, the surface temperature of the material rises to the boiling point so fast that it can avoid the melting caused by heat conduction. As a result, part of the material vaporizes into steam and disappears, and part of the material is blown away from the bottom of the slit as an ejecta by the auxiliary gas flow.

2. Melt cutting.

When the power density of the incident laser beam exceeds a certain value, the material will evaporate and form a hole. Once the hole is formed, it will act as a blackbody to absorb all the incident beam energy. The hole is surrounded by a molten metal wall, and then the molten material around the hole is taken away by an auxiliary air flow coaxial with the beam. With the movement of the workpiece, the small hole moves horizontally synchronously according to the cutting direction to form a cutting seam. The laser beam continues to irradiate along the front edge of the seam, and the molten material is continuously or Pulsatively blown away from the seam.

3. Oxidation melting cutting.

In general, inert gas is used in melting cutting. If oxygen or other active gas is used instead, the material will be ignited under the irradiation of laser beam, and another heat source will be produced by the fierce chemical reaction with oxygen, which is called oxidation melting cutting.

4. Control fracture cutting.

For brittle materials which are easy to be damaged by heat, high-speed and controllable cutting by laser beam heating is called controlled fracture cutting. The main content of this cutting process is: the small area of brittle material is heated by laser beam, which causes large thermal gradient and serious mechanical deformation in this area, and causes cracks in the material. As long as the uniform heating gradient is maintained, the laser beam can guide the crack to generate in any direction.
















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