In this article, you will get the laser cutting basics, including definition, working principle, laser cutting types, laser cutting features, laser cutting applications and trends in future.

Definition

Laser cutting is to use a high-power density laser beam to irradiate the material to be cut, so that the material is quickly heated to the vaporization temperature and evaporates to form a hole. As the beam moves the material, the hole continuously forms a slit with a narrow width to complete the material cut.

Principle

The laser uses substance excitation to generate light. This light has a strong temperature. When contacting the material, it can quickly melt on the surface of the material to form a hole. According to the movement of the registration point, the cutting is formed. Compared with the traditional cutting method, the cutting method has a smaller gap and can save most of the material. However, the analysis is defined according to the cutting effect. The material that is cut according to the laser has a satisfactory cutting effect and high accuracy. This is inherited In addition to the advantages of laser, it is also unmatched by ordinary cutting methods. Laser cutting is to use a focused high power density laser beam to irradiate the workpiece, so that the irradiated material quickly melts, vaporizes, ablate or reaches the ignition point, and at the same time, the molten material is blown off by the high-speed air flow coaxial with the beam, thereby cutting the workpiece open. Laser cutting is one of the thermal cutting methods.

Types

Laser cutting can be divided into four categories: laser vaporization cutting, laser melting cutting, laser oxygen cutting, laser scribing and controlled fracture.

1. Laser vaporization cutting

Using a high-energy density laser beam to heat the workpiece, the temperature rises rapidly, reaches the boiling point of the material in a very short time, and the material begins to vaporize to form steam. The ejection speed of these vapors is very large, and at the same time as the vapors are ejected, a cut is formed in the material. The heat of vaporization of materials is generally very large, so laser vaporization and cutting requires a lot of power and power density.

2. Laser melting cutting

In laser melting cutting, the metal material is melted by laser heating, and then the non-oxidizing gas (Ar, He, N, etc.) is sprayed through the nozzle coaxial with the beam, and the liquid metal is discharged by the strong pressure of the gas to form a cut. Laser melting cutting does not need to completely vaporize the metal, and the energy required is only 1/10 of the vaporization cutting.

3. Laser oxygen cutting

The principle of laser oxygen cutting is similar to oxyacetylene cutting. It uses a laser as a preheating heat source and an active gas such as oxygen as a cutting gas. On the one hand, the blown gas interacts with the cutting metal to cause an oxidation reaction and emit a large amount of heat of oxidation; on the other hand, the molten oxide and melt are blown out from the reaction zone to form a cut in the metal. Because the oxidation reaction in the cutting process generates a lot of heat, the energy required for laser oxygen cutting is only 1/2 of the melting cutting, and the cutting speed is much faster than the laser vaporizing cutting and melting cutting. Laser oxygen cutting is mainly used for easily oxidized metal materials such as carbon steel, titanium steel and heat-treated steel.

Features

Compared with other thermal cutting methods, laser cutting has the overall characteristics of fast cutting speed and high quality. Specifically summarized as the following aspects.

Good cutting quality Due to the small laser spot, high energy density, and fast cutting speed, laser cutting can obtain good cutting quality.

a. Laser cutting incision is narrow, both sides of the slit are parallel and perpendicular to the surface, and the dimensional accuracy of the cut parts can reach ±0.05mm.

b. The cutting surface is smooth and beautiful, the surface roughness is only tens of microns, and even laser cutting can be used as the last process, without mechanical processing, and the parts can be used directly.

c. After the material is laser cut, the width of the heat affected zone is very small, the performance of the material near the slit is almost not affected, and the workpiece deformation is small, the cutting accuracy is high, the geometry of the slit is good, and the cross-sectional shape of the slit is more Regular rectangle.

2. High cutting efficiency Due to the transmission characteristics of the laser, the laser cutting machine is generally equipped with multiple CNC worktables, and the entire cutting process can be fully CNC controlled. During operation, only need to change the numerical control program, it can be applied to the cutting of parts of different shapes, both two-dimensional cutting and three-dimensional cutting.

Trends

1. The laser cutting machine will continue the epoch-making product revolution.

The laser light source is the core component of the laser cutter, and also an important indicator that determines the type and cutting ability of a laser cutter. Needless to say, future changes in laser cutters will also occur in laser light sources. As mentioned above, the replacement of CO2 laser cutting machine by fiber laser cutting machine is the most important technological revolution in the 40 years since the laser cutter was born, which has brought epoch-making economic benefits to manufacturers and new and old users in this field. So, in the future, will there be a new light source that is cheaper than fiber lasers, has better performance, more excellent beam mode, higher electro-optic conversion rate or lower overall cost? The answer is of course yes. Then ask, what kind of laser? Of course, it is impossible to give an accurate answer now. Science and technology sometimes falter, sometimes thousands of miles a day.

2. High-power fiber laser will become the main force in the laser cutting machine market. Nowadays, optical fiber cutting machines of various power ranges have ushered in great development. However, where is the mainstream laser power of laser cutter machines in the future? Although the laser cutting machines in each power range have their own use, but the family of lasers that started with high-power fiber lasers and triggered the global laser cutting machine technology revolution, regard higher power, higher precision, and greater cutting capacity as One of the important development directions of fiber laser cutting machine.