The laser cutting process is divided into:
Vaporization cutting
Under the heating of the high power density laser beam, the surface temperature of the material rises to the boiling point temperature so fast that it avoids the melting caused by heat conduction, so that some of the material vaporizes into vapor and some of the material is ejected from the bottom of the slit. The auxiliary gas stream is blown away.
2. Melt cutting
When the power density of the incoming laser beam exceeds a certain value, the inside of the material at the beam irradiation point evaporates to form a hole. Once such a small hole is formed, it will absorb all of the incoming 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 simultaneously traversed in the cutting direction 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.
3. 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.
4. Control 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.
