The development momentum of the sheet metal industry is very rapid, and its position and weight in the market are becoming more and more important, which not only brings huge economic benefits to our enterprises, but also brings convenience to the production and life of our residents. The application and assistance of advanced laser cutting in matching sheet metal processing will become the key to improve the overall technical level of the domestic sheet metal industry. The laser cutting technology is developing with the development of the sheet metal industry. Today, we propose corresponding solutions to common problems in the processing of optical fiber laser cutting machine:
1. Incision and perforation skills
Any kind of hot cutting skills, except for a few situations that can start from the edge of the board, usually must have a small hole punched in the board. Before, a punch was used to punch a hole on the laser punching compound machine, and then the laser was used to cut from the small hole. There are two basic methods for piercing laser cutting machines without punching equipment:
Pulse perforation&mdash& mdash; Pulse laser with peak power is selected to melt or vaporize a few materials. Air or nitrogen is often used as auxiliary gas to reduce the hole expansion due to exothermic oxidation. The gas pressure is lower than the oxygen pressure when cutting. Each pulse laser only produces small particle eruption and gradually deepens, so the thick plate perforation time needs a few seconds. Once the perforation is completed, we will replace the auxiliary gas with oxygen for incision. In this way, the perforation diameter is smaller, and the perforation quality is better than that of explosive perforation. For this reason, the laser used should not only have high output power; What is more important is the temporal and spatial characteristics of the beam. In addition, the pulse perforation must also have a reliable gas circuit control system to complete the switching of gas varieties, gas pressures and the control of the perforation time.
Explosion perforation&mdash& mdash; The data is illuminated by successive lasers to form a pit in the middle, and then the molten data 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, and the uniform diameter of the explosive perforation is half of the plate thickness. Therefore, the hole diameter of the explosive perforation for thicker plates is large and not round. It is not suitable for use on parts with high machining accuracy requirements, and can only be used on waste materials. In addition, as the oxygen pressure used for perforation is the same as that used for incision, the spatter is large.
2. Analysis of burr on workpiece during laser cutting and processing of stainless steel and aluminum coated zinc plate
For the presentation of the above conditions, we should first consider the element of burr when cutting low carbon steel, but we should not simply accelerate the cutting speed. Because the adding speed sometimes shows that the plate cannot be cut through, which is particularly outstanding when processing aluminum coated zinc plate. At this time, other elements of the machine tool should be summarized and considered to solve the problem, such as whether the nozzle should be replaced, and the motion of the guide rail is unstable.
3. Analysis of the deformation of the cut hole
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 converge too much in a small area, scorching the non processing area, forming hole deformation and affecting the processing quality. At this time, we should change the pulse perforation method to explosive perforation method in the processing program to solve the problem. On the contrary, for the laser cutting machine with lower power, the method of pulse piercing should be adopted to obtain better surface finish when machining small holes.
4. Solution to abnormal spark when cutting low carbon steel
This condition will affect the machining quality of the cut section finish of the part. At this moment, when other parameters are normal, the following conditions should be considered: the NOZZEL loss of the laser head nozzle should be replaced in time. When there is no new nozzle replacement, the gas pressure for cutting operation shall be increased; The thread of the nozzle and the laser title joint is loose. At this moment, stop cutting immediately, check the connection of the laser head, and put the thread on the head.
5. Solution to the burr of workpiece when laser cutting low carbon steel
According to the operation and planning principle of laser cutting, the following reasons are analyzed and concluded as the primary reasons for forming burrs on machined parts: the upper and lower orientations of laser focus are incorrect, so focus orientation test is required, and adjustment is made according to the offset of focus; 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, investigate whether the output value of the laser control button is correct and adjust it; The linear speed of cutting is too slow, so it is required to increase the linear speed during operation and control; The purity of cutting gas is poor, and high-quality cutting gas is required; Laser focus shift, focus orientation test is required, and adjustment is made according to the focus shift; The machine tool is unstable when it runs for too long. At this moment, it needs to be shut down and restarted.
6. Analysis of incomplete laser penetration
After analysis, it can be found that the following conditions are the primary conditions for unstable processing: the selection of laser nozzle does not match the thickness of the processing plate; The laser cutting line speed is too fast, and the operation control is required to reduce the line speed; The azimuth difference between the nozzle induction rejection and the laser focus is large, so the nozzle induction data should be detected from scratch, especially when cutting aluminum.