Metal laser cutting is one of the important applications of current laser technology. With the development of fiber laser pointer technology, metal laser cutting has gradually become the main market for laser applications, and laser cutting equipment has gradually become the main force to replace traditional metal cutting equipment.
In fact, the cutting process of a metal laser cutting machine is essentially different from traditional machining by machining. Metal laser cutting is to irradiate a laser beam to the surface of a metal workpiece, and achieve the purpose of cutting or engraving by melting and evaporating the metal workpiece. Laser cutting has the advantages of accuracy and speed, unlimited modes, saving materials, smooth end faces, and low comprehensive processing costs.
From the original division, metal laser cutting can be divided into the following categories:
1) Vaporized cutting
Use high energy density laser beam to heat the workpiece. It vaporizes in a short period of time to form steam. Make cuts in the material. The heat of vaporization of materials is generally very large, so high power and power density are required for laser vaporization and cutting.
2) Melt cutting
In laser melting and cutting, the metal material is melted by laser heating, and the nozzle is sprayed with non-oxidizing gas (Ar, He, N, etc.), and the liquid metal is discharged by the strong pressure of the gas to form an incision. The energy required is only 1/10 of that of vaporized cutting. Laser melting cutting is mainly used for cutting some non-oxidized materials or active metals, such as stainless steel, titanium, aluminum and their alloys.
3) Oxygen cutting
It uses a green laser pointer as a preheating heat source and an active gas such as oxygen as the cutting gas. On the one hand, the blown gas reacts with the cutting metal to generate oxidation reaction and release a large amount of oxidation heat; on the other hand, the molten oxide and melt are blown out of the reaction zone, and the cutting speed is much faster than laser vaporization and melting cutting. Laser oxygen cutting is mainly used for easily oxidized metal materials such as carbon steel, titanium steel and heat-treated steel.