Sheet Metal Laser Cutting

Four classifications of laser cutting

Sheet metal laser cutting can be divided into four categories: laser vapor cutting, laser melting cutting, laser oxygen cutting and laser scribing and controlled fracture.

1. Laser vapor cutting

Using a high energy density laser beam to heat the workpiece, the temperature rises rapidly and reaches the boiling point of the material in a very short period of time, and the material begins to vaporize and form vapors. These vapors are ejected at a large rate, and while the vapors are ejected, a cut is formed in the material. The heat of vaporization of the material is generally very large, so a high power and power density is required for laser vapor cutting.

Laser vapor cutting is mostly used for cutting very thin metal materials and non-metal materials (such as paper, cloth, wood, plastic and rubber, etc.).

2. Laser melting cutting

In laser fusion cutting, the metal material is melted by laser heating, and then 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 kerf. Laser melting cutting does not require complete vaporization of the metal and requires only 1/10 of the energy of vapor cutting.

Laser melting cutting is mainly used for some materials that are not easy to oxidize or the cutting of reactive metals, such as stainless steel, titanium, aluminum and its alloys, etc.

3. Laser oxygen cutting

Laser oxygen cutting principle is similar to oxyacetylene cutting. It is the use of laser as a preheating heat source, with oxygen and other reactive gases as the cutting gas. The gas blown out on the one hand with the cutting metal, the oxidation reaction occurs, releasing a large amount of oxidation heat; on the other hand, the molten oxide and molten material is blown out of the reaction area, forming a kerf in the metal. Since the oxidation reaction during the cutting process produces a large amount of heat, the energy required for laser oxygen cutting is only 1/2 of that for melting cutting, while the cutting speed is much greater than that for laser vapor cutting and melting cutting. Laser oxygen cutting is mainly used for carbon steel, titanium steel and heat treatment steel and other easily oxidized metal materials.

4. Laser scribing and controlled fracture

Laser scribing is the use of high energy density laser scanning on the surface of brittle materials, so that the material is heated to evaporate a small groove, and then apply a certain pressure, the brittle material will be cracked along the small groove. The lasers used for laser scribing are generally Q-switched lasers and CO2 lasers.

Controlled fracture uses the steep temperature distribution created when the laser scribes the groove to create a local thermal stress in the brittle material, causing the material to break along the small groove.