It is inevitable that problems will occur during the use of laser cutting machine. So how to solve these problems? Take a look at the following 7 questions. Have you encountered any of them during operation?
1. Cutting and perforating technology of laser cutting machine:
Any thermal cutting technology, except for a few cases starting at the edge of the plate, usually requires a small hole in the plate. Previously, on the laser stamping composite machine, a punch was used to punch out a hole, and then we used the laser to start from the small hole for research and cutting. There are two basic methods to penetrate the laser cutting machine without a punch:
Blasting perforation-the material can form a pit in the center after continuous use of laser irradiation, and then the oxygen flow coaxial with the laser beam quickly melts the material and removes the students to form such a hole. In general, the size of the hole is related to the thickness of the plate. The average diameter of the blasting hole is half the thickness of the plate. Therefore, the diameter of the blasting hole of a thicker plate is larger rather than circular, which is not suitable for parts with higher processing precision requirements. Only waste. In addition, the oxygen environment pressure used for perforation is the same as that of cutting, so the splashing effect is greater.
Pulse perforation - uses high peak power pulsed laser to melt or evaporate a small amount of material. Air or nitrogen is often used as auxiliary gas to reduce the expansion of cavities caused by exothermic oxidation. The gas pressure is less than the oxygen pressure during cutting. Each pulse of the laser only produces a small particle jet, which gradually develops deeper, so we need a few seconds to perforate thick plates. Once the perforation is completed, oxygen is used instead of auxiliary gas for cutting. In this way, the perforation diameter is less affected, and the perforation quality is better than blasting perforation. The laser used for laser cutting must not only have a high output power, but also have the time and space characteristics of the beam, so the general cross-flow CO2 laser cutting machine cannot meet the requirements of laser cutting. In addition, pulse perforation also requires a more reliable gas path control management system to achieve the switching of different types of these gases, gas environment pressure and perforation time control.
In order to obtain high-quality cutting, attention should be paid to the transition technology from pulse punching when the workpiece is stationary to constant speed continuous cutting. In theory, the cutting technical conditions of the acceleration section of the enterprise can usually be changed, such as focal length, nozzle position, gas pressure, etc., but in fact, it is unlikely to change more than one of these conditions because the working time is too short. In industrial production, it is feasible to change the average laser power by changing the pulse width, pulse frequency, pulse width and pulse frequency. The actual research results show that the third method has the best effect.
2.Deformation analysis of small hole cutting process of laser cutting machine:
This is because our Chinese machine tools (only for these high-power laser cutting machine do not use the blasting perforation method when processing small holes, but use pulse perforation (soft puncture), which makes our laser energy too concentrated in a small area, and burns the non-processing area, causing the hole to deform and affect the quality of the production and processing products. At present, in the processing process, the pulse perforation (soft perforation) method should be changed to the blasting perforation (ordinary perforation) method to solve this problem. For a smaller power laser cutting machine, laser cutting machine is just the opposite. Different pulse perforation methods should be adopted in small hole processing to achieve better surface finish.
3. Solution to burr problem when laser cutting machine cuts low carbon steel:
According to the basic principles of CO2 laser cutting machine work and teaching design, the following reasons can be analyzed to be the main reasons for burr generation in processed parts: the upper and lower positions of the laser focus are incorrect, and a focus position test needs to be done, and timely adjustment is made according to the offset of the social focus; the output power of the laser is not enough, and we need to check whether the staff of the laser generator can work normally. If not, observe whether the output numerical method of the laser technology control system button should be correct and make adjustments; the cutting line speed is too slow, and the line speed needs to be increased during actual operation risk control; the purity of the cutting gas is not enough, and it is necessary to develop and provide economical and high-quality cutting management working environment gas; the laser focus is offset, and a focus position test needs to be done, and it is constantly adjusted according to the offset of the focus; the instability caused by the long operation time of the machine tool, at this time the teacher needs to shut down and restart.
4. Analysis of the generation of burrs on workpieces when laser cutting stainless steel and galvanized steel:
When the above situations occur, we first need to consider the factors that cause burrs when cutting low-carbon steel, but it is inevitable to simply speed up the cutting speed, because the speed can be increased. Sometimes the plate will not be cut through, which is particularly important when processing galvanized steel. At this time, we should consider whether the nozzle should be replaced, unstable guide rail movement and other factors to solve.
5. Analysis of the laser cutting machine's incomplete cutting state:
After analysis, we can find that the following different situations are the main development situations that affect the unstable processing quality: the selection of the laser head nozzle does not match the thickness of the processed plate; the laser cutting line speed is too fast, and we need to control the operating system to reduce the line speed; the nozzle inaccurate sensing leads to a large error in the laser focus position, and the nozzle sensing data needs to be re-detected, especially when cutting aluminum.
6. Treatment of abnormal sparks in low-carbon steel cutting:
This development situation will affect the quality of the product of the cut section finish of the parts. If other parameters are normal at this time, the following conditions should be considered: the laser head nozzle NOZZEL is lost, and the nozzle should be replaced in time. In the absence of a new nozzle for replacement, the pressure of the gas passing through the cutting management working environment should be increased; the thread at the connection between the nozzle and the laser head is loose. At this time, we should immediately suspend cutting, check the working status of the laser head connection, and re-thread it.
7. Protect the lens to produce water mist:
In the cutting process of the laser cutting machine, auxiliary gas is indispensable! Among them, oxygen and nitrogen are commonly used in our country. Of course, the higher the purity of the gas, the better the quality of the cutting work. Many customers want to save the cost of air cutting, but there is always fog to protect the lens during the cutting process, and the cutting quality is very poor. Why?
First of all, let us popularize the role of auxiliary gas:
1. To blow away the residue to achieve the best cutting effect.
2. Use these gases to blow away the metal slag while protecting the lens to prevent the slag from sticking to the lens and affecting the quality of the cutting work.
3. It can effectively achieve a smooth cutting surface, no burrs, and no slag effect, which belongs to fine cutting.
4. It can produce adverse reactions with material development and increase the cutting speed. For example, by using oxygen, the effect of combustion can be achieved.
Therefore, in order to achieve better cutting effects, the requirements for auxiliary gases are higher! Although we can use air as auxiliary gas in our country, the ambient air contains moisture and oil. If one is not treated, it will cause lens pollution and unstable cutting head, so that the cutting technology effect and quality are not up to standard. Therefore, when using air cutting, it is necessary to equip the fiber laser cutting machine with a cold dryer, which solves this problem well. The cold dryer can force the compressed air to be cooled to the required dew point temperature below, so that the large amount of water vapor and oil mist contained therein can be condensed into droplets, and discharged from the machine by the drainer through gas-liquid separation, so that the compressed air environment is dry.