Laser cutting is a high-tech modern industrial revolution in the use of technology in developed countries is a very high penetration rate of industrial-grade production equipment, through the control of a computer program, a good flexible manufacturing, largely replaced the metal sheet metal stamping die processing sectors, to optimize the production processes in the field of machinery and equipment manufacturing plays an irreplaceable role. So what are the main laser cutting process?
Heating at high power density laser beam, the surface temperature is raised to the boiling temperature of the speed is so fast enough to avoid melting caused by heat conduction, so part of the material is vaporized into steam disappeared, as part of the material was discharged from the bottom of the slit is secondary gas stream blown away. Some can not be melted material, such as wood, carbon materials, and some plastics is through this vaporization method of cutting forming.
Vaporization process, the steam take with molten particle erosion and debris, the formation of holes. Vaporization process, about 40% of the material turned into steam disappeared, while 60% of the material is in the form of droplets by air purged.
2, melting cutting.
When the incident laser beam power density exceeds a certain value, the internal beam irradiated material at the point to open mom evaporation, the formation of holes. Once the hole is formed, it will serve as a blackbody absorbs all incident beam energy. Holes are surrounded by molten metal wall, then, coaxial with the beam of the secondary air flow around the hole of the molten material away. With the movement of the workpiece, the hole formed by the cutting direction synchronous traverse a slit. Continue along this seam laser beam irradiation forefront, continuous or pulse melting material being blown away from the seam.
3, oxidation melting cutting.
Usually an inert gas is molten cut, if replaced by oxygen or other reactive gas, material is ignited by irradiation of the laser beam, other heat generating violent chemical reaction with oxygen, called oxidative cleavage melted. Described as follows:
(1) surface by irradiation of the laser beam is heated to ignition temperature quickly, along with oxygen intense combustion reaction and emit a lot of heat. In this action of heat, internal material filled with steam hole, and the hole is surrounded by molten metal wall surrounded.
(2) combustion of oxygen-transporting substance to control slag and metal combustion speed while oxygen diffuses through the slag to reach the ignition speed of the leading edge also has a great influence on the burning rate. The higher the flow rate of oxygen, combustion chemistry and the faster removal of slag. Of course, the oxygen flow rate is not as high as possible, because the flow rate too fast will cause the slit at the outlet of the reaction product of a metal oxide that is cooled rapidly, which is unfavorable for the cutting quality.
(3) Obviously, the oxidation melting cutting process there are two heat sources, the laser irradiation and the chemical reaction of oxygen with the metal thermal energy. It is estimated that cutting steel, the oxidation reaction heat released to account for around 60% of the total required to cut energy.
Obviously, compared with an inert gas, the use of oxygen as an auxiliary gas can obtain higher cutting speeds.
(4) has two heat sources in the oxidation melting cutting process, if the oxygen burning faster than the moving speed of the laser beam, slotted appear broad and rough. If the laser beam is moving faster than the speed of oxygen combustion, the resulting narrow slit and smooth.