Laser processing is after machining, power processing, flame processing and processing power of a new processing technology. As a very unique light source, also called "knife" that can solve manufacturing problems processing, molding, preparation of different materials. As magical "knife", it has many features: its spatial energy distribution characteristics may be needed "sharp" to "blunt", with time characteristics, continuous or modulated output, according to the absorption coefficient is processed materials, its wavelength cover to the ultraviolet. Various optical parameters of the match, the workpiece may range from metal, composite materials, materials, ceramics, glass, leather, cloth, etc. to man-made fibers, and other new materials.
Currently, laser processing laser than infrared. According to absorb the laser energy and the temperature of the material produced increases, it can be laser-material interaction process is divided into the following phases:
1, no heat or basic stages.
From the microscopic, the laser is engaged degeneracy when its density is very low, most of the incident photons are elastically scattered electrons in the material, the main physical process of this reflection, transmission and absorption.
2, the heating phase transformation point.
When the incident laser intensity increase, incident photons and electrons in metals inelastic scattering of electrons by "inverse bremsstrahlung effect" energy from photons. In the excited state of the electron-phonon interaction, the phonon energy to inspire strong vibration, so that the material is hot. When the temperature is lower than the phase transition point, material does not change the result.
3, above the melting point of the phase transition point but heated.
This stage solid phase change material, the presence of heat and mass transfer physics.
4, above the melting point but below the vaporization point heating.
Laser melts the material, forming a puddle. Bath outside the main heat, the pool of memory in three kinds of physical processes: heat transfer, convection and mass transfer.
5, the vaporization point than heating phenomenon.
Laser vaporizes material to form a plasma, this deep penetration welding is a phenomenon often seen in the laser.