When using laser cutting machine to cut metal, various problems may occur, which seriously affect the work efficiency. What should we do? Summarize some methods to solve common problems in metal laser cutting.
Solution to the perforation problem of thick metal plate
Generally speaking, for any kind of thermal cutting technology, it is necessary to drill a small hole in the metal sheet, except for a few cases that may start from the edge of the metal sheet. Previously, a hole was punched with a punch pin in a laser imprinting machine, and then cut from the small hole with a laser.
Therefore, there are two basic methods that can be used for laser cutting machine drilling without punching device.
Pulse perforation
Pulsed lasers with peak power are used to melt or vaporize small amounts of material.
Air or nitrogen is usually used as an auxiliary gas to reduce cavity expansion caused by exothermic oxidation. The air pressure during cutting is lower than the oxygen pressure.
Due to the steam pressure generated, small particles are thrown out of the borehole. Each pulsed laser produces only a few small particles, which gradually become deeper, so it usually takes a few seconds for thick metal plates to pierce.
After perforation, replace the auxiliary gas with oxygen for cutting.
In this way, the perforation diameter is much smaller, and the perforation quality is better than that of sand blasting.
The laser used for this purpose should not only have higher output power, but also, more importantly, better beam time and space control characteristics.
In addition, more reliable pneumatic control system is required for pulse perforation to realize gas type, gas pressure switching and perforation time control.
In the case of pulse piercing, in order to obtain high-quality cuts, the transition technology from pulse piercing when the workpiece is stationary to continuous cutting at constant speed should be seriously considered.
In theory, it is usually possible to change the cutting conditions of the acceleration part, such as focal length, nozzle position, air pressure, etc., but in fact, because the time is too short, the above conditions are unlikely to change. In industrial production, the method of changing the average laser power is mainly adopted. The specific methods are as follows: (1) Change the pulse width; (2) Change the pulse frequency; (3) Change the pulse width and frequency at the same time. The practical results show that (3) the effect is the best.
Blast hole
After the material is irradiated by a continuous laser, a pit is formed in the center, and then the molten material is rapidly removed by an oxygen flow coaxial with the laser beam, thereby forming a hole. In general, the size of the hole is related to the thickness of the plate. The average diameter of the blast hole is half the thickness of the steel plate. Therefore, the hole diameter of the sandblasting hole of the thicker plate is large and not round, so it is not applicable to parts with higher requirements (such as oil mesh joint pipe), but only applicable to debris. In addition, because the oxygen pressure used for perforation is the same as that used for cutting, the spatter is large.
Solution to Burr in Cutting Low Carbon Steel with Metal Laser Cutting Machine
According to the working and design principles of laser cutting, the following reasons are the main causes of workpiece burrs:
If the focus is not in the correct position, focus position test shall be carried out to correct the deviation
The output power of the laser is insufficient. It is necessary to check whether the laser generator works normally. If it is normal, please check whether the output value of the laser control button is correct, and then adjust it accordingly.
The cutting line speed is too slow, so the line speed needs to be increased during operation;
The purity of the gas is not enough, and high-quality cutting working gas must be provided.
If the laser focus shifts, it is necessary to perform the focus position test and adjust the offset accordingly.
Since the laser cutter will be unstable if it runs for a long time, you should shut down the machine and restart it.
Solution to Burr in Cutting Stainless Steel and Aluminum Zinc Plate with Metal Laser Cutting Machine
In this case, you should first consider the factors that may cause burrs during low-carbon steel cutting. However, you should not simply increase the speed, as this may lead to incomplete cutting of stainless steel and aluminum zinc plates.
This problem is particularly serious when processing aluminum zinc plates. In this case, other factors of the machine tool should be comprehensively considered, such as whether the nozzle should be replaced, and whether the guide rail motion is unstable.
Solution to Incomplete Cutting of Metal Plate
The main reasons for incomplete metal plate cutting are:
·The nozzle of the laser head does not match the thickness of the processing plate, please replace the nozzle.
·The linear speed of laser cutting is too fast, reducing the linear speed;
·It is not allowed to use the nozzle to sense the laser focus position. If the error is too large, it is necessary to re detect the nozzle sensing data, which is easy to occur when cutting aluminum.
Solution to Abnormal Spark in Laser Cutting Low Carbon Steel
This will affect the quality of the cut part. In this case, if there is no problem with other parameters, the following situations should be considered:
·The laser head nozzle is worn, please replace it in time. In case of shortage of new nozzles, increase the air pressure of laser cutting.
·The thread at the joint between the nozzle and the laser head is loose. In this case, stop cutting quickly, check the connection status and tighten the thread.
Hole Deformation in Metal Laser Cutting
This is because pulse perforation will be used when machining small holes with high-power laser cutting machine, which will cause laser energy to concentrate on small areas, resulting in burns in the unprocessed area and hole deformation.
In this case, change the pulse puncture (soft puncture) method to sand blasting puncture (normal puncture) in the processing program.
For small power laser cutting machine, pulse piercing shall be adopted in small hole processing to obtain good surface finish.
I hope these solutions can help you solve the problems in metal laser cutting. If you have any questions, please contact us for further discussion.