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The laser cutting section will form vertical lines, and the depth of the lines determines the roughness of the cutting surface. The shallower the lines, the smoother the cutting section. Roughness affects not only the appearance of the edge, but also the friction characteristics. In most cases, the roughness needs to be minimized, so the shallower the texture, the better the cut quality.
solution
When cutting carbon steel, problems such as insufficient lightness of the thin plate section and rough section of the thick plate are generally encountered.
Generally speaking, a 1000W laser can cut no more than 4mm of carbon steel, 2000W is 6mm, and 3000W is 8mm.
1. Glitch
The formation of burrs is a very important factor that determines the quality of laser cutting. Because the removal of burrs requires extra work, we can intuitively judge the quality of cutting through the amount and degree of burrs.
solution
First, check whether there is any problem with the laser output, whether the light spot is very round, and whether the light spot is coaxial with the center hole of the nozzle. The circular light spot indicates that the horizontal distribution of laser energy is uniform, and the energy distribution of the light spot formed after being focused by the lens is also more uniform, and the cutting quality is better; the better the coaxiality between the light spot and the central hole of the nozzle, the better the cutting quality.
Secondly, check whether the lenses and lenses during the laser transmission process have fine particles, dust, splashing residues and other objects that affect the cutting quality, and whether the lenses have small cracks that are not easily found by the naked eye, which will affect the transmission of laser power.
After the above two points are checked, it can be determined whether the laser itself is good. Then comes the adjustment of process parameters.
The burrs produced by laser cutting of stainless steel have a certain hardness, which is very time-consuming to remove, and also affects the appearance of the workpiece. It is best to solve it from the root cause: the purity of the gas is critical, and it is best not to use cylinder gas. The second is to adjust the cutting parameters to the best, and the air pressure flow, focal length cutting speed, etc. must be adjusted many times.
Equipment + gas + parameters (adjusted to the best) = less burr to cut the workpiece
2. Deformation
In laser cutting, the area around the cut is heated. At the same time, the structure of the metal changes. For example, some metals will harden.
Depression and corrosion have a detrimental effect on the surface of the cut edge, affecting the appearance, and they appear in cutting errors that should generally be avoided. If the cut causes the part to heat up sharply, it will deform.
solution
This is especially important in fine machining, where contours and webs are usually only a few tenths of a millimeter wide. Controlling the laser power and using short laser pulses can reduce part heating and avoid deformation.
3. Not cut through
Laser cutting is a complex process, and in the process of cutting, it is often encountered that the cut cannot be cut through. There are many reasons why the sample cannot be cut through. The most common one is the power drop of the laser or the aging of the lamp tube, which makes the energy of the laser beam insufficient, causing the sample to not be cut through. The cutting speed is too fast, the focusing lens is damaged, the focusing effect is poor, the optical path is not correct, and the voltage is unstable. These are the reasons why the laser cutting cannot cut through. Of course, there are many factors that cause the sample to be impenetrable, such as the problem of the material itself, the insufficient air pressure of the auxiliary gas, the turbid water in the cooling system, and the poor heat dissipation effect.
solution
(1) The cutting speed should be appropriately reduced, the contaminated mirror should be cleaned in a timely and reasonable manner, and the focusing lens should be replaced.
(2) For the problem of incorrect optical path, the optical path can be readjusted, and the focal length can be adjusted until the laser hits a spot on the paper that is concentric with the center of the nozzle.
(3) When cutting copper and aluminum, it is best to polish the surface in advance or apply light-absorbing material to deal with the problem of high reflectivity.
(4) Regularly clean the foreign matter in the nozzle, increase the pressure of the auxiliary gas, and replace the distilled water of the cooling system in time.
4. Material discoloration
The color change near the cut when stainless steel is cut is mainly due to the oxidation of the material at high temperatures. Stainless steel is not only a high temperature resistant material, but also a thermal insulation material due to its poor thermal conductivity. When we are cutting these materials, due to their slow thermal conductivity, a higher temperature will be generated and accumulated near the cut, so the stainless steel at high temperature will oxidize in the air. Depending on the temperature, the depth of oxidation is also different, resulting in different colors.
In addition, too slow cutting speed, incorrect focus, and low gas purity can cause surface discoloration of the sheet.
solution
(1) The material is too hot, cool the material.
(2) The feed rate is too low, increase the feed rate.
(3) If the focal length of the material and the laser head is not correct, use the locator to test and adjust the focal length.
(4) The air pressure is too low, increase the air pressure.
(5) Nitrogen contains oxygen impurities, use nitrogen with good quality and high purity.
