The light cutting process is divided into

The light cutting process is divided into:
1. Vaporization cutting:
Under the heating of a high-power density laser beam, the surface temperature of the material rises rapidly to the boiling point temperature, which is sufficient to avoid melting caused by thermal conduction. As a result, some of the material vaporizes into steam and disappears, while others are blown away as ejecta from the bottom of the cutting seam by an auxiliary gas flow.
2. Melting cutting:
When the power density of the incident laser beam exceeds a certain value, the material inside the beam irradiation point begins to evaporate, forming holes. Once this small hole is formed, it will act as a blackbody to absorb all the energy of the incident beam. The small hole is surrounded by a molten metal wall, and then an auxiliary airflow coaxial with the beam carries away the molten material around the hole. As the workpiece moves, the small hole synchronously moves horizontally in the cutting direction to form a cutting seam. The laser beam continues to shine along the front edge of this seam, and the melted material is continuously or pulsating blown away from inside the seam.
3. Oxidation melting cutting:
Melting cutting generally uses inert gases. If oxygen or other active gases are used instead, the material is ignited under the irradiation of a laser beam, and a violent chemical reaction occurs with oxygen to produce another heat source, which is called oxidation melting cutting. The specific description is as follows:
(1) The surface of the material is quickly heated to the ignition temperature under the irradiation of a laser beam, and then undergoes intense combustion reactions with oxygen, releasing a large amount of heat. Under the action of this heat, small holes filled with steam are formed inside the material, surrounded by molten metal walls.
(2) The transfer of combustion substances into slag controls the combustion rate of oxygen and metal, while the speed at which oxygen diffuses through the slag to reach the ignition front also has a significant impact on the combustion rate. The higher the oxygen flow rate, the faster the combustion chemical reaction and slag removal rate. Of course, the higher the oxygen flow rate, the better, because too fast a flow rate can cause rapid cooling of the reaction products, namely metal oxides, at the exit of the cutting seam, which is also detrimental to the cutting quality.
(3) Obviously, there are two heat sources in the process of oxidation melting cutting, namely the laser irradiation energy and the thermal energy generated by the chemical reaction between oxygen and metal. It is estimated that the heat released by oxidation reaction during steel cutting accounts for about 60% of the total energy required for cutting. It is evident that using oxygen as an auxiliary gas can achieve higher cutting speeds compared to inert gases.
(4) In the oxidation melting cutting process with two heat sources, if the combustion speed of oxygen is higher than the movement speed of the laser beam, the cutting seam appears wide and rough. If the speed of laser beam movement is faster than the combustion speed of oxygen, the resulting slit will be narrow and smooth. [1]
4. Control fracture cutting:
For brittle materials that are prone to thermal damage, high-speed and controllable cutting through laser beam heating is called controlled fracture cutting. The main content of this cutting process is to heat a small area of brittle material with a laser beam, causing a large thermal gradient and severe mechanical deformation in that area, resulting in the formation of cracks in the material. As long as a balanced heating gradient is maintained, the laser beam can guide cracks to occur in any desired direction.