Laser cutting machine is a dynamic melting process. The size of the molten pool is small. There are not only heat transfer phenomena, but also convection and mass transfer, which directly affect the macro morphology, segregation, uniformity of structure and composition and other physical and metallurgical properties of the molten pool. Therefore, study the heating theory of laser cladding and clarify the problems of heat conduction, convection and mass transfer in the process of laser cladding, It is of great significance to clarify the theory of laser cladding.
Laser cutting machine technology is a new technology with high economic benefits. It can prepare high-performance alloy surfaces on cheap metal substrates without affecting the properties of the substrate, reducing costs and saving precious and rare metal materials. Therefore, the research and application of laser cladding technology are highly valued in the world's advanced industrial areas.
Laser cutting machines used in laser cladding mainly include CO2 lasers and solid-state lasers. Scholars at home and abroad have done a lot of research on continuous CO2 laser cladding. The development of high-power solid-state lasers is rapid, mainly used for surface modification of non-ferrous alloys. It is reported in the literature that when CO2 laser is used for laser cladding of aluminum alloy, the aluminum alloy matrix is easy to deform or even collapse under the condition of CO2 laser irradiation. Solid state laser is 1 order of magnitude smaller than CO2 laser wavelength, so it is more suitable for laser cladding of such metals.
Under the control of the computer, the laser cutting machine discharges the laser through pulses, so as to output a controlled repetitive high-frequency pulse laser, forming a beam with a certain frequency and pulse width. The pulse laser beam is transmitted and reflected through the optical path, and focused on the surface of the processed object through the focusing lens group, forming a fine, high-energy density light spot, which is located near the surface to be processed, Melt or vaporize the processed material at an instant high temperature. The high-energy laser pulse instantly splashes a small hole on the surface of the object. Under the control of the computer, the cutting head of the laser cutting machine and the processed material conduct continuous relative motion dot according to the pre drawn figure to process the object into the desired shape.