Outline of the hottest laser cutting technology an

2022-08-04
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Outline of laser cutting technology and precision of laser cutting

the laser beam is focused into a very small light spot, whose minimum diameter can be less than 0.1mm, so that the focus can reach a very high power density of more than 106W/cm2. At this time, the heat input by the beam (converted by light energy) far exceeds the part reflected, conducted or diffused by the material. The material will soon be heated to the vaporization humidity and evaporated to form holes. With the relative linear movement of the light beam and the material, the holes continuously form a slit with a very narrow width (such as about 0.1mm). The thermal effect of trimming is very small, and there is basically no workpiece deformation. Auxiliary gas suitable for the material to be cut is also added during the cutting process. When cutting steel, oxygen is used as an auxiliary gas to produce exothermic chemical reaction with molten metal to oxidize the material and help blow away the slag in the slit. Compressed air is used to cut polypropylene and inert gas is used to cut cotton, paper and other flammable materials. The auxiliary gas entering the nozzle can also cool the focusing lens to prevent soot from entering the lens seat to pollute the lens and cause the lens to overheat

most organic and inorganic materials can be cut by laser. In the metal processing industry, which accounts for a large proportion of industrial manufacturing, many metal materials, regardless of their hardness, can be shaped and cut without deformation (at present, using the most advanced laser cutting system can reduce the energy consumption of 100million tons of standard coal, and the thickness of industrial steel can be close to 20mm). Of course, for high reflectivity materials, such as gold, silver, copper and aluminum alloys, they are also good heat transfer conductors, so laser cutting is very difficult, or even impossible (some difficult cutting materials can be cut with pulse wave laser beam. Due to the extremely high peak power of pulse wave, the absorption coefficient of the material to the beam will be sharply increased in an instant)

laser cutting has no burr, wrinkle and high precision, which is superior to plasma cutting. For many mechanical and electrical manufacturing industries, because the modern laser cutting system with microcomputer program can easily cut workpieces with different shapes and sizes (the workpiece drawing can also be modified), it is often preferred to punching and die pressing process; Although its processing speed is slower than that of die punching, it has no die consumption, no need to repair the die, and saves the time to replace the die, thus saving processing costs and reducing product costs. Therefore, it is more economical in general

on the other hand, from the perspective of how to make the mold adapt to the changes of workpiece design size and shape, laser cutting can also give play to its advantages of accuracy and good reproducibility. As a preferred manufacturing method for laminated molds, since there is no need for senior mold makers, and the symbol of laser cutting operation cost is not expensive, the mold manufacturing cost can be significantly reduced. The additional benefit of laser cutting die is that a shallow hardening layer (heat affected zone) will be produced during die cutting, which improves the wear resistance of the die during operation. The non-contact characteristic of laser cutting brings non stress advantage to the cutting and forming of circular saw blade, which improves the service life

laser cutting of common engineering materials

1 Laser cutting of metal materials

although almost all metal materials have high reflectivity to infrared wave energy at room temperature, lamp pumped nd:yag lasers and 10.6 μ MC2 laser has been successfully applied to laser cutting practice of many metals

2 Laser cutting of non-metallic materials 10.6 μ The m-wavelength CO2 laser beam is easy to be absorbed by non-metallic materials when the price rises again. The poor thermal conductivity and low evaporation temperature make the absorbed beam almost input into the material, and vaporize instantly at the spot irradiation, forming initial holes and entering the virtuous cycle of the cutting process

precision of laser cutting

the precision of laser cutting is composed of many factors:

1. The size of the spot after the laser beam passes through the focus

the smaller the spot after the laser beam is gathered, the higher the cutting precision until it is suitable for conditioning. In particular, the slit is small, and the smallest spot can reach 0.01mm

2. The positioning accuracy of the workbench determines the repetition accuracy of cutting.

the higher the accuracy of the workbench, the higher the cutting accuracy

3. The greater the thickness of the workpiece, the lower the precision and the larger the cutting seam

because the laser beam is conical, the cutting seam is also conical. The stainless steel with a thickness of 0.3mm is much smaller than that with a thickness of 2mm

4. Workpiece material has certain influence on laser cutting accuracy

in the same case, the cutting accuracy of stainless steel is higher than that of aluminum, and the cutting surface is smoother

the laser cutting machine has good cutting quality. Narrow notch width (generally 0.1--0.5mm), high precision (generally 0.1--0.4mm hole center distance error, 0.1--0.5mm contour dimension error), good notch surface roughness (generally RA is 12.5--25 μ m) Generally, the cutting seam can be welded without further processing

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