1. Controlled fracture cutting
For brittle materials that are easily damaged by heat, high-speed, controlled cutting by laser beam heating is called controlled fracture cutting. The main content of this cutting process is that the laser beam heats a small area of brittle material, causing a large thermal gradient and severe mechanical deformation in the area, causing the material to form cracks. As long as a balanced heating gradient is maintained, the laser beam can direct the crack to occur in any desired direction.
2. Vaporization cutting
At high power (referring to the amount of work done by the object in a unit of time), the temperature of the surface of the material rises to the boiling point temperature so fast that it is sufficient to avoid melting caused by heat conduction, so that part of the material vaporizes. The steam disappears and some of the material is blown away as an effluent from the bottom of the slit by the auxiliary gas stream.
3. Melt cutting
When the incident laser beam power density exceeds a certain value, the inside of the material at the beam irradiation point begins to evaporate, forming a hole. Once such a small hole is formed, it will absorb all of the incident beam energy as a black body. The aperture is surrounded by the molten metal wall and then an auxiliary gas stream coaxial with the beam carries away the molten material around the hole. As the workpiece moves, the small holes are traversed in the direction of the split to form a slit. The laser beam continues to illuminate along the leading edge of the slit, and the molten material is blown away from the slit continuously or pulsatingly.
4. Oxidation melting cutting
Melting and cutting generally uses an inert gas. If replaced by oxygen or other reactive gas, the material is ignited under the irradiation of a laser beam, and a strong chemical reaction with oxygen produces another heat source called oxidative melting cutting.