Common faults and solutions of laser cutting machines 2

Common faults and solutions of laser cutting machines

  1. Cutting and perforating technology Any kind of hot cutting technology, except for a few cases where it can start from the edge of the board, usually must pass a small hole in the board. Previously, on the laser stamping compound machine, a punch was used to punch a hole, and then a laser was used to cut from the small hole. For laser cutting machines without punching equipment, there are two basic methods of perforation: pulse perforation - use pulsed laser with high peak power to melt or vaporize a small amount of material, and often use air or nitrogen as auxiliary gas to reduce the damage caused by exothermic oxidation. As the hole expands, the gas pressure is lower than the oxygen pressure during incision. Each pulsed laser produces only a small eruption of particles, which gradually deepens, so it takes several seconds for the thick plate to perforate. Once the perforation is completed, immediately switch the auxiliary gas to oxygen for incision. In this way, the diameter of the perforation is smaller, and the perforation quality is better than that of the explosive perforation. The laser used for this purpose should not only have high output power; more importantly, the time and space characteristics of the beam, in addition, the pulse perforation also needs a more reliable gas circuit control system to complete the switching of gas types, gas pressure and Manipulation of piercing moments. Explosive perforation - The material is irradiated by a continuous laser to form a pit in the middle, and then the molten material is quickly removed by the oxygen flow coaxial with the laser beam to form a hole. Usually the size of the hole is related to the thickness of the plate. The average diameter of the explosion perforation is half of the plate thickness. Therefore, for thicker plates, the diameter of the explosion perforation is larger and not round. It is not suitable for parts with high machining accuracy requirements. on waste. In addition, since the oxygen pressure used for perforation is the same as for incision, the splash is larger.

2. When laser cutting stainless steel and aluminum-zinc-coated sheet, the workpiece has burrs to analyze the above situation. The first consideration is the factors that cause burrs when cutting low carbon steel, but it is not easy to speed up the cutting speed, because the addition speed sometimes increases. It appears that the sheet is cut and not worn, and this condition is particularly good when processing aluminum-zinc sheets. At this time, other elements of the machine tool should be considered and solved, such as whether the nozzle should be replaced, and the movement of the guide rail is unstable.

 

  1. Analysis of the deformation state of the small holes in the cutting process This is because the machine tool does not use the method of explosive perforation when processing the small holes, but the method of pulse perforation, which makes the laser energy too concentrated in a small area and will not be processed. The area is also charred, forming a deformation of the hole, affecting the quality of the machining. At this time, we should change the pulse perforation method to the explosive perforation method in the processing program to solve it. As for the laser cutting machine with lower power, it is just the opposite. In the process of small hole processing, the method of pulse perforation should be adopted to obtain a better surface finish.

  1. Solution for abnormal sparks when cutting mild steel This situation will affect the quality of the cut surface finish of the part. At this moment, when other parameters are normal, the following conditions should be considered: the loss of the laser head nozzle NOZZEL should be replaced in time. In the absence of replacement of new nozzles, the gas pressure of the cutting operation should be increased; the thread at the connection between the nozzle and the laser head is loose. At this moment, the incision should be stopped immediately, the connection status of the laser head should be checked, and the thread should be re-threaded.

 

  1. When laser cutting low carbon steel, the solution to the burr on the workpiece is based on the operation and planning principle of laser cutting, and the following reasons are analyzed to form the primary reason for the burr of the workpiece: the upper and lower orientation of the laser focus is incorrect, and the demand Do the focus orientation test and adjust it according to the offset of the focus; if the output power of the laser is not good, you need 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 line speed of opening is too slow, and it is necessary to increase the line speed during operation and control; the purity of the cutting gas is not good, and high-quality cutting operation gas needs to be supplied; the laser focus is shifted, and a focus orientation test needs to be performed, according to the shift of the focus The amount of adjustment; the instability of the machine tool running time is too long, and now it needs to be shut down and restarted.

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