Common faults and solutions of laser cutting machines

1 Cutting and piercing skills

Any kind of eager cutting skill, except for a few situations that can start from the edge of the board, usually a small hole must be drilled in the board. Previously, a punch was used to punch a hole on a laser punching compound machine, and then a laser was used to cut the hole from the end. There are two basic methods of perforating for laser cutting without punching equipment:

Pulse perforation-select high peak power pulse laser to melt or vaporize a small number of materials. Air or nitrogen is often used as auxiliary gas to reduce the expansion of the hole due to exothermic oxidation. The gas pressure is lower than the oxygen pressure during cutting. Each pulse laser only emits small particles, which gradually deepen, so it takes a few seconds to perforate thick plates. Once the perforation is completed, Lixing replaces the auxiliary gas with oxygen to perform the incision. In this way, the diameter of the perforation is smaller, and the perforation quality is better than that of the explosive perforation. For this reason, the laser used should not only have a higher output power; more importantly, the time and space characteristics of the beam. In addition, pulse perforation also requires a more reliable gas path control system to complete the switching of gas types and gas pressures. Manipulation at the moment of perforation.

Explosive perforation-the material is irradiated by successive lasers to form a pit in the middle, and then the molten material is quickly removed to form a hole by the oxygen flow coaxial with the laser beam. Usually the size of the hole is related to the thickness of the plate. The average diameter of the explosive perforation is half of the thickness of the plate. Therefore, the explosive perforation has a larger aperture for thicker plates and is not round. It is not suitable for use on parts with higher machining accuracy. On the waste. In addition, since the oxygen pressure used for perforation is the same as that for cutting, the splash is larger.

2.Analysis of burrs on the workpiece during laser cutting and processing of stainless steel and aluminum-zinc plate

In the above situation, we should first consider the elements of burrs when cutting low carbon steel, but it is not possible to simply accelerate the cutting speed. Due to the addition speed, the sheet will sometimes appear to be cut and not penetrated. This situation is used in the processing of aluminum-zinc sheets. The time is particularly outstanding. At this time, other elements of the machine tool should be summarized and resolved, such as whether the nozzle should be replaced, the guide rail movement is unstable, and so on.

3.Analysis of the deformation of the small hole in the cutting process

This is because the machine tool does not adopt the method of explosive perforation when processing small holes, but uses the method of pulse perforation, which makes the laser energy too concentrated in a small area, scorching the non-processing area, and forming hole deformation , Affect processing quality. At this time, we should change the pulse perforation method to the explosive perforation method in the processing program to solve it. On the other hand, the laser cutting machine with lower power is just the opposite. The pulse perforation method should be adopted to obtain a better surface finish when processing small holes.

4.Solutions for abnormal sparks when cutting low carbon steel

This condition will affect the processing quality of the cut section finish of the part. At this moment, when other parameters are normal, the following conditions should be considered: the loss of the nozzle of the laser head, and the nozzle should be replaced in time. If there is no replacement of a new nozzle, the gas pressure of the cutting operation should be increased; the thread at the junction of the nozzle and the laser head is loose. At this moment, the cutting should be suspended immediately, the laser head connection status should be checked, and the thread should be installed from the head.

5.The solution to the burr on the workpiece when laser cutting low carbon steel

According to the operation and planning principle of laser incision, it is analyzed that the following reasons are the primary reasons for the formation of burrs on the processed parts: the upper and lower positions of the laser focus are not correct, and the focus position test needs to be done, and adjustments are made according to the offset of the focus; The output power of the laser is not good. It is necessary to check whether the operation of the laser generator is normal. If it is normal, check whether the output value of the laser control button is correct and adjust it; the cutting line speed is too slow, and it needs to be increased during operation and control. Linear speed; the purity of the cutting gas is not good, and high-quality cutting gas is required; the laser focus is shifted, and the focus position test is required to adjust according to the shift of the focus; the instability of the machine running time is too long At this moment, it needs to be shut down and restarted from the beginning.