Laser cutting technology is a cutting technology that uses laser to process planes. It has attracted the attention of many scholars due to its advantages such as high processing precision and no pollution. With the continuous development and progress of science and technology, people have put forward higher requirements for the performance of parts, so the methods and equipment for processing parts are constantly updated and improved. Most traditional parts are made by mechanical processing methods. Mechanical processing has shortcomings such as low processing efficiency and poor environmental friendliness. Laser processing just solves these problems. Laser cutting technology uses a laser generator to output a high-energy-density laser beam. The laser beam scans the processing surface and melts and vaporizes in local areas to achieve rapid prototyping. In the field of cutting-edge processing, laser processing is used in the design of micro-mechanical structures. It can maintain the dimensional accuracy of micro-structure parts and has the advantages of high cutting efficiency, fast speed, good quality, and environmental protection. There have been certain studies at home and abroad on the interaction between laser and materials and the optimization of laser cutting parameters, which have promoted the development of laser cutting. This article will introduce the principles and research and development history of laser cutting processing technology, including related theoretical research on laser cutting, laser cutting technology and equipment.
Research on laser cutting technology and equipment
To study the relationship between laser cutting process parameters and laser cutting quality, some scholars have explored the optimization of laser processing process parameters through experiments, which has a certain promoting effect on improving laser processing quality. This study uses Nd:YAG pulse laser to explore the influence of process parameters on slit quality and slit width. Research has found that as the laser frequency, pulse width and power density increase, the laser slit width also increases, and the increase in laser output repetition frequency helps to improve processing quality, cutting speed and processing efficiency. Laser power and laser cutting speed affect the quality of the workpiece such as surface roughness and slit width. The study found that under certain other conditions, the increase in cutting speed will reduce the kerf width and reach a certain stable value, while the increase in laser power will increase the kerf width. In addition, the influence of laser power and laser cutting speed on the roughness of the material cutting surface shows an opening upward parabola. The factors affecting laser cutting accuracy were explored through laser cutting experiments on steel plates. Taking 1.5mm thick steel plate as the research object, by changing the cutting direction and beam compensation and other process parameters, laser cutting the sample, and then measuring and comparing the difference between the measured size and the set value, so as to obtain the process parameters that affect the accuracy. The study found that the direction of laser cutting has little impact on accuracy, the path distribution of laser cutting has a greater impact on accuracy, and the amount of defocus has a certain impact on cutting accuracy. The finite element analysis software ANSYS is used to establish a three-dimensional model of laser-cut sheet metal parts, and explore the analysis and calculation method of the deformation of the cutting workpiece under the combined action of the gravity of the sheet metal parts and the laser heat source. The laser heat source is simplified to a Gaussian heat source, and the APDL language is used to calculate and analyze the deformation of the laser cutting workpiece. The study found that it is of great help to the corresponding fixture design for laser cutting sheet metal parts. To study the laser cutting of 316L stainless steel sheets, by establishing a mathematical model of forming parameters, material properties and cutting width, obtain their mathematical relationships, and test the accuracy of the model through a pulse laser cutting system. Research has found that laser cutting width is positively related to laser frequency, power, beam diameter, and pulse width. The cutting width is negatively related to the specific heat, scanning speed, vaporization enthalpy, and melting specific enthalpy of the processed material. Wen Jinwei et al. [25] studied the main process parameters that affect the seam shape and seam width of laser cutting circular die-cutting plates, obtained better process parameter data, and cut a 1.42mm rectangular seam. Using pulse laser to cut circular die-cutting plates keeps the blade body in proper contact with the cutting seam, thereby improving the strength, stiffness and service life of the circular die-cutting plates. The study found that the amount of defocus and laser power have a greater impact on the slit width. , in order to get the appropriate seam width, some adjustments need to be made. First adjust the defocus amount and laser power to determine the upper slit width. Then, adjust the cutting speed and determine the width of the lower seam so that the width and size of the upper seam and the lower seam tend to be consistent, and a rectangular seam is cut. If the slit size is too tight or too loose, fine-tune the repetition frequency until the appropriate slit width is finally obtained. To study the high-power CO2 laser cutting process of small round holes in medium-thick steel plates, the CO2 laser cutting system of Rofin DC 025 laths was used to explore the cutting process of laser cutting d = 5mm small holes in 6mm thick A3 steel plates. By studying the effects of cutting speed, laser power and oxygen pressure on laser cutting quality, and analyzing the decisive role of temperature distribution at the cutting front on laser cutting quality. The study found that when the laser power is 1kW, the laser cutting speed is 1.0m/min, and the oxygen pressure is 1.2×105 Pa, laser cutting of small round holes in medium-thick steel plates can achieve the best results and improve cutting quality.
Technical difficulties and development trends of laser cutting
1) The laser cutting system has a single function. Nowadays, laser cutting technology has been widely used, but its single cutting function cannot be further developed in production applications. The industry needs composite laser cutting. Germany’s TRUMPF TruMatic 3000 fiber fiber optic composite machine can realize functions such as laser cutting, blanking and laser welding, solving the problem of single function of laser cutting. Therefore, composite function laser processing centers and three-dimensional laser cutting robots are the development trend of laser cutting. (2) The level of localization of lasers is not high. The laser is the core component of the system, and the technical threshold for lasers is high, among which fiber lasers are particularly prominent. Core components such as laser pumps, high-power optical devices and high-power gain optical fibers require long-term technology accumulation. At present, foreign giants IPG Photonics, Nufern, SPI, Coherent and JDSU have long controlled most of the world’s laser market, of which IPG lasers account for half. However, domestic lasers have just started, and many of their performances are not as good as foreign products. Therefore, it is necessary to enrich the theory of laser cutting and improve the performance of domestic lasers. (3) Cutting technology. The current cutting machine operates at a low speed and the cutting process parameters are imperfect. Develop CNC laser cutting machines with dedicated cutting process parameters and a laser-specific automatic programming system. If the cutting process can be significantly improved, laser cutting will reach a higher level.
Conclusione
Laser cutting technology has been industrialized at home and abroad, but there is still a certain gap between my country’s laser cutting technology and foreign countries. This article describes the research progress of domestic and foreign researchers on laser cutting-related aspects from the aspects of laser theory and technology. Scholars conduct experimental and theoretical research from various angles with the goal of improving laser processing quality. At the end of the article, the future development trend of laser processing technology is analyzed based on the difficulties of laser processing technology. In the future, it is necessary to continuously update the relevant theories of laser cutting technology and accelerate the research of related laser equipment.
