What are the types of laser cutting machines?

Laser cutting uses laser instead of physical cutting tools or high-temperature flame cutting. Due to the characteristics of laser, it has significant advantages over traditional cutting.In addition to the power of laser cutting, the optical properties of the laser have the greatest impact on cutting,Such as wavelength, pulse width, pulse repetition frequency, etc.Depending on the type of laser, the current industrial laser equipment is mainly divided into fiber laser, CO2 laser and YAG laser.

Fiber Laser

Fiber laser is a kind of laser system that uses glass fiber doped with rare earth elements as gain medium. It consists of three parts: gain medium, pump source and resonant cavity. Generally, semiconductor laser is used as pump source, and resonant cavity is generally composed of reflector, fiber end face, fiber ring mirror or fiber grating and other devices. Active fiber with rare earth elements (erbium (Er3+), ytterbium (Yb3+), neodymium (Nd3+), samarium (Sm 3+), thulium (Tm3+), holmium (Ho3+), praseodymium (Pr3+), dysprosium (Dy3+), bismuth (Bi3+), etc.)) is used as gain medium.

Depending on the doped ions, fiber lasers can achieve laser outputs of different wavelengths. The wavelength used in industry is generally 1.06um (one tenth of the wavelength of CO2 laser), so it is particularly suitable for cutting thin metal plates.

Advantages of fiber lasers

Good beam quality: The waveguide structure of the optical fiber determines that the fiber laser is easy to obtain single transverse mode output, and is less affected by external factors, and can achieve high-brightness laser output.Using this type of laser has a small straight-edge cut and a smooth cut surface, and can obtain a large depth-to-diameter ratio and depth-to-width ratio.

High photoelectric conversion efficiency: The electro-optical conversion efficiency can reach 20%~30% (CO2 lasers are generally 8%~10%). The extremely high energy conversion efficiency makes this type of laser more energy-saving and generates less heat. Low-power equipment can use an air-cooling system, and the power requirements of the water-cooling machine used in high-power equipment are also reduced accordingly.

High cutting speed: The cutting speed can reach 4~5 times that of YAG laser cutting machine.

High equipment stability and simple maintenance:The optical path is simple, no complicated reflectors are required, it is less affected by the external environment, and the subsequent maintenance cost is low.

Low cost of use: The extremely high electro-optical conversion efficiency can save more electricity, the simple optical path system makes the subsequent maintenance cost very low, and no gas medium is used, saving related costs.

Harmless to human body: Laser wavelength is infrared light that is invisible to the human eye and poses no harm to the human body.

Disadvantages of fiber lasers

Cutting material limitation: Fiber laser cannot cut non-metallic materials, nor can it cut materials with a coating on the surface, such as ordinary coated stainless steel, special steel plates with anti-rust coating, etc.

High initial cost: The initial purchase of a fiber laser cutting machine is higher, but the subsequent operating costs are much lower.

CO2 Laser

CO2 laser is a gas laser, which is the representative of “vibration-rotation molecular laser” in gas laser. Its working gas is a mixture of CO2, N₂ and He. The electrons in the atoms remain in the ground state, and the laser transition occurs between two rotational energy levels of different vibration states of CO2.