Laser cutting is the use of focused high power density laser beam irradiation of the workpiece so that the irradiated material quickly melts, vapors, ablation or reaches the ignition point, at the same time with the coaxial high-speed airflow and light beam blowing molten material, so as to achieve the workpiece cut. Laser cutting is one of the thermal cutting methods.
1, high speed, high precision laser cutting machine
Because of the improvement of beam mode of high power laser and the application of 64-bit microcomputer, it creates favorable conditions for the high speed and high precision of laser cutting equipment. At present, the cutting speed of the international advanced laser cutting machine has reached more than 20m/min, the fast movement of two axes can reach 250m/min, the acceleration Z is 109, and the positioning accuracy can reach 0.01mm/500mm.
High speed, high precision laser cutting machine, in the cutting plate thickness of 1mm, the diameter of 10mm small circle, can cut more than 500 per minute, and its diameter error is not more than 50mm, to achieve the true sense of flight cutting technology.
2, thick plate cutting and large size workpiece cutting large laser cutting machine
With the increase of laser power can be used for laser cutting from light industrial sheet metal processing towards heavy industry thick plate cutting direction.
6kW high-power laser can cut large size workpiece of 32mm thickness of low carbon steel plate. Due to the continuous improvement of thick plate laser cutting technology, it has been tried to use a 3kW laser to cut 32mm thick low carbon steel plate, which usually needs to be cut by a 6kW laser, and has been used for trial production. In addition, the processing size range of laser cutting machines is also expanding, the current production of Z large laser cutting machine width up to 5.4m, up to 6m. This shows that thick plate, large size laser cutting technology is gradually improving.
3, three-dimensional multi-axis CNC laser cutting machine
In order to meet the three-dimensional workpiece cutting needs of automotive, aviation, and other industries, we have developed a variety of 5 axes or 6 axes 3D laser cutting machines, its Z large processing workpiece size can reach 3500mm×1200mm, the number of CNC axis up to 9 axes, fast processing speed, high accuracy, in the range of 6.2m processing error is only within 0.1mm.
Laser cutting is the use of high power, high-density laser beam irradiation is cut material, so as to instantaneous high temperature to vaporize the material, and evaporation formed holes, with the displacement of the laser beam, holes by point into line, forming a continuous slit, so as to achieve the effect of cutting material. In recent years, with the continuous maturity and application of electronic information engineering and computer technology, laser cutting has achieved digital control, and cutting accuracy has also been greatly improved, promoting the development of mechanical processing and cutting technology.
All concentrated heat is the melting or separation of materials, collectively referred to as thermal cutting. Laser cutting and other thermal cutting methods (flame cutting, arc cutting) are compared with their main characteristics in the following aspects.
1, laser cutting quality is better
The laser beam can be adjusted appropriately according to the different requirements of cutting accuracy. In the field of machining, the accuracy of laser spot diameter can reach 0.1mm. With the use of these light diameter cutting machine parts, not only the surface of the cutting mouth is smooth, there will be no obvious burr, to meet the needs of the use of mechanical parts in most cases, and the slit facade is parallel to each other, the geometry of the machined parts is good. For general mechanical parts, the use of laser cutting does not need additional size calibration, and grinding processing can be directly used.
2, laser cutting efficiency is higher
Technology fusion has become the mainstream trend in the modern machinery industry. Combining laser cutting with information technology and numerical control technology, not only improves the laser cutting progress but also significantly improves the cutting efficiency. At present, the use of a CNC workbench control laser cutting machine, through the control of program instructions, can cut different shapes of mechanical parts, greatly improving the cutting efficiency.
For example, there is a 1500W laser machine, cutting thickness of 3mm low carbon steel plate, Z high cutting speed can reach 6×103mm/min, if it is cutting resin materials, cutting speed can also be increased to 1×104mm/min above.
3, laser cutting material variety
Laser cutting can not only process common metal materials and non-metal
materials but also can be used to process leather products, wood fiber, and so
on. Of course, for different material products, the adaptability of laser
cutting will also be different, in the cutting process should be a reasonable
Measuring laser cutting process and machining quality parameters mainly include laser power incision width, cutting speed, etc., in addition, beam quality, defocusing amount, etc., will also affect the overall quality of laser cutting to a certain extent.
1, laser power
The main factor that determines the laser power of the laser, is the greater the laser power, the faster the cutting speed, and the better the cutting effect. In addition to being restricted by its own hardware conditions, laser power is also affected by external factors, including the nature of the cutting material, the thermal conductivity of the material, etc.
For example, if the surface of the cutting material is smooth, the reflectivity of light is high, then the utilization efficiency of the laser is high, and the cutting effect is better; If the cutting material is a benign thermal conductor, the heat of the cutting point can quickly spread to other parts of the mechanical material, it is easy to produce "hot zone effect", prone to material deformation or rough incision and other problems.
2, cutting speed
Factors affecting the laser cutting speed are varied, such as the use of different cutting processes to cut different mechanical materials and the size of the cutting gas pressure. Generally speaking, the higher the laser energy, the smaller the material thickness, the greater the cutting gas pressure, the faster the cutting speed, and vice versa.
It should be noted that we should not blindly pursue laser cutting speed when we are in mechanical processing, but also take into account the quality of laser cutting. In particular, some mechanical parts with high precision requirements must be required to achieve a certain level of laser cutting accuracy to ensure the availability of machined parts.
3. Gas pressure
Laser cutting blowing gas has the following functions: one is used to melt cutting metal materials and rely on the pressure of blowing gas-liquid metal blown away, forming an incision; The second is used for oxygen melting cutting, gas and cutting metal reaction heat, can provide part of the cutting energy. However, the gas has a cooling effect on the material and can take some energy away from the cutting zone. So gas has an important effect on cutting quality. Different nozzles use different gas flows.
At a certain power and cutting material thickness, there is the best cutting gas flow, and the cutting speed is determined. And the increase of laser power, cutting gas Z flow increases. No matter what kind of laser cutting, the need for scientific control of gas pressure, not only to ensure that the gas can blow out molten metal and oxide but also to prevent irregular incision, affect the quality of laser cutting.
4. Beam quality, lens focal length, and defocus quantity
The laser beam output mode for the transverse mode of laser cutting is very advantageous. Smaller spots and higher power densities can be obtained after focusing. The results show that the incision width is almost equal to the laser spot diameter in non - oxygen-assisted cutting. The size of the spot is proportional to the focal length of the focusing lens. A lens with a short focal length can produce a smaller spot of light and a smaller focal depth.
The focal depth used in laser processing technology is defined as: if the power density of a certain cross-section ZX of the beam is 50% of the focal point, the distance between this point and the focal point is the focal depth. The smaller the focal depth, the thinner the plate can be cut, and the distance between the workpiece surface and the lens is strict. When cutting thick plates, a focusing lens with a larger focal length should be selected. Defocus has a great impact on cutting speed and cutting depth, cutting to remain the same, usually, defocus to choose a negative value, the focus position is at a point below the surface of the cutting board.
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