Laser cutting can be classified into four categories: laser vaporization cutting, laser melting cutting, laser oxygen cutting, and laser scribing and controlled fracture.
1. Laser Vaporization Cutting: This method uses a high-energy-density laser beam to heat the workpiece, causing the temperature to rise rapidly and reach the material's boiling point in a very short time. The material begins to vaporize, forming vapor. This vapor is ejected at a high velocity, creating a cut in the material simultaneously. The heat of vaporization is generally very high, so laser vaporization cutting requires high power and power density.
Laser vaporization cutting is often used for cutting extremely thin metallic and non-metallic materials (such as paper, cloth, wood, plastics, and rubber).
2. Laser Melting Cutting: In laser melting cutting, the metal material is melted by laser heating. Then, a non-oxidizing gas (Ar, He, N, etc.) is blown through a nozzle coaxial with the laser beam. The strong pressure of the gas forces the liquid metal out, forming a cut. Laser melting cutting does not require complete vaporization of the metal, and the energy required is only 1/10 of that required for vaporization cutting.
Laser melting cutting is mainly used for cutting materials that are not easily oxidized or reactive metals, such as stainless steel, titanium, aluminum, and their alloys.
3. Laser Oxygen Cutting
Laser oxygen cutting is similar in principle to oxyacetylene cutting. It uses a laser as a preheating heat source and reactive gases such as oxygen as the cutting gas. The blown gas reacts with the metal being cut, causing an oxidation reaction and releasing a large amount of heat of oxidation; simultaneously, it blows the molten oxides and melts out of the reaction zone, forming a cut in the metal. Because the oxidation reaction during the cutting process generates a large amount of heat, the energy required for laser oxygen cutting is only half that of melting cutting, while the cutting speed is much greater than laser vaporization 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.
4. Laser Scribing and Controlled Fracture
Laser scribing uses a high-energy-density laser to scan the surface of a brittle material, causing the material to heat up and evaporate into a small groove. Then, a certain pressure is applied, causing the brittle material to crack along the groove. Laser scribing typically uses Q-switched lasers and CO2 lasers.
