With the rapid development of the automobile industry, consumers’ requirements for automobile safety performance, comfort and appearance design are constantly increasing. As the basic structure of the automobile, the welding quality of the automobile body is directly related to the overall quality and service life of the automobile. Therefore, advanced automobile body welding technology occupies an important position in the automobile manufacturing industry. This paper analyzes the current advanced automobile body welding technology and its application.
Advanced automobile body welding technology plays a vital role in the automobile manufacturing industry. With the rapid development of the automobile industry, consumers’ requirements for automobile quality and safety performance are constantly increasing. As a key process in automobile manufacturing, the technical level of body welding technology directly affects the overall performance and manufacturing quality of the automobile. In the automobile manufacturing process, body welding technology mainly faces the following challenges: (1) Changes in body materials, such as the widespread use of high-strength steel, aluminum alloy and other materials; (2) Differences in the thickness of body parts, which need to adapt to welding of different thicknesses; (3) Diversification of welding trajectories and joint forms, requiring welding technology to have a high degree of flexibility; (4) High requirements for welding quality and welding efficiency. The application of laser welding technology in automobile body manufacturing mainly includes laser deep melting welding, laser wire welding, laser brazing and laser arc hybrid welding. These processes take advantage of the advantages of laser welding technology to achieve high-precision, high-strength, and lightweight body manufacturing.
1.1 Laser deep penetration welding
Laser deep penetration welding is a type of laser welding technology. It uses a high-energy-density laser beam to produce local melting on the surface of the workpiece to form a deep molten pool. After focusing, the laser beam can produce high energy density in a small area, causing the material to melt rapidly. Laser deep penetration welding can form a deeper molten pool inside the material, thereby achieving full penetration welding of the material. The fast propagation speed of the laser beam allows the welding process to be carried out at high speed, thereby improving production efficiency. The heat-affected zone of laser welding is small, which reduces welding deformation and stress and maintains the performance of the material. By controlling laser parameters (such as power, pulse width, frequency, etc.) and the welding process, the welding quality can be precisely controlled.
Laser deep penetration welding technology is becoming one of the key technologies in modern manufacturing with its rapid development speed and broad application prospects. With the introduction of new laser sources, such as fiber lasers and ultrafast lasers, this technology is increasingly used in high-end fields, showing its incomparable advantages. In the automotive industry, the application of laser welding technology has greatly improved the accuracy and safety of body assembly, and promoted the realization of lightweight body. Laser self-melting welding technology, with its high energy density, makes the metal melt and vaporize in an instant to form a stable deep molten hole, providing a high-quality solution for the welding, assembly welding and component welding of automobile bodies. Technological innovation is the core driving force for the development of laser welding technology. The application of new lasers, such as blue and green lasers, provides efficient solutions for the welding problems of highly reflective materials such as copper, significantly improving welding efficiency and quality. In addition, the introduction of new processes such as swing welding technology and ARM annular adjustable spot welding has further enhanced the adaptability and flexibility of laser welding technology and solved some problems in the traditional welding process. In the future, the development of laser welding automation technology will pay more attention to the deep integration with robotics and artificial intelligence to achieve a high degree of automation and intelligence in the production process. This will not only optimize the adaptive control and real-time monitoring of the welding process, but also improve production efficiency and product quality through intelligent optimization, while effectively reducing production costs.
1.2 Laser filler wire welding
Laser filler wire welding technology is a variant of laser welding technology. It combines the advantages of filler wire welding and laser welding and is suitable for the connection of coated metals, especially galvanized steel plates. Filler wire welding can compensate for the error of the workpiece assembly gap, making the precision requirements for workpiece processing and assembly relatively low. Filler wire welding technology has brought revolutionary innovation to the field of laser welding with its excellent flexibility and controllability. Through the selection of filler wire materials, even thicker or larger workpieces can be welded with lower-power lasers. The filler wire not only significantly increases the total amount of molten pool metal, effectively bridges a larger weld gap, but also promotes the full formation of the weld, thereby significantly improving the overall quality and performance of the weld.
By adjusting the composition of the filler wire, the welding process can achieve precise control of the microstructure and properties of the weld area, specifically make up for the performance deficiencies of the parent material, and optimize the weld joint. In this process, the precise control of key parameters such as laser power, spot size, and welding speed is particularly critical, which together determine the stability of welding and the excellent quality of the weld. Process parameters such as wire feeding speed and shielding gas flow rate also need to be carefully adjusted according to material properties and welding requirements to ensure the optimization of welding effect. Comprehensive inspection of weld quality is also indispensable, including appearance inspection, non-destructive testing and mechanical property testing. These inspection methods jointly ensure that the internal and external quality and mechanical properties of the weld meet the highest standards. With the continuous advancement of laser technology and the reduction of costs, laser wire welding technology is rapidly expanding its application areas. Its efficient, flexible and high-precision welding capabilities have brought unprecedented welding solutions to modern manufacturing, driving industrial manufacturing to move towards higher quality and higher precision.
2 Laser welding technology
Laser welding technology is an advanced welding process that uses a high-energy-density laser beam to weld metal materials. This technology is commonly used in the automotive industry, especially in the manufacture of lightweight body structures. The laser beam has a high energy density and can heat the metal material to above the melting point in a very short time, achieving deep melting welding with a small heat-affected area. The laser beam can be precisely controlled to achieve precise welding paths and welding parameters, thereby obtaining high-quality welds. The fast propagation speed of the laser beam, coupled with highly concentrated energy, enables laser welding technology to complete welding in a shorter time and improve production efficiency. Compared with traditional welding methods, laser welding technology has a smaller heat-affected zone, reduces welding deformation and stress, and improves the dimensional accuracy of the welded structure. Laser welding technology can weld a variety of different materials, such as high-strength steel, aluminum alloy, stainless steel, etc., and has strong adaptability. The laser welding process can be automated and controlled, and combined with robotics technology to improve the stability and consistency of the welding process. In the field of automobile manufacturing, laser welding technology is often used to manufacture body structural parts, such as side panels, floor panels, wheel covers, etc. It can produce body parts that are both light and have high strength and impact resistance by splicing metal sheets of different materials and thicknesses.
3.1 Programmable welding robot
Programmable welding robot is an automated welding equipment that performs welding operations in a pre-programmed manner. This type of robot is usually used for large-scale welding tasks on production lines, which can improve production efficiency, ensure the consistency of welding quality, and reduce the labor intensity of workers. The main features and advantages of programmable welding robots are high degree of automation. Through computer programming, automatic control of welding path and welding parameters can be realized to improve production efficiency. Due to the good repeatability of the robot, the consistency of welding quality can be ensured and the quality fluctuation caused by manual operation can be reduced. Programmable welding robots can quickly replace welding heads and adjust welding parameters to meet the needs of different workpieces and welding processes. Programmable welding robots can be integrated with other equipment on the production line to realize welding automation assembly line operation. Programmable welding robots can reduce labor demand in welding operations and reduce production costs. In practical applications, programmable welding robots need to be equipped with appropriate welding heads (such as argon arc welding heads, carbon dioxide gas shielded welding heads, etc.), sensors (such as visual sensors, laser ranging sensors, etc.) and control systems. Through precise control of parameters such as welding path, welding speed, welding current, welding voltage, etc., programmable welding robots can achieve various complex welding tasks.
3.2 Electron beam welding
Electron beam welding is a high-energy beam welding technology that uses a high-speed electron beam as a heat source to weld the workpiece in a vacuum or in a gas-protected atmosphere. Electron beam welding technology has the characteristics of high energy density, good controllability, and pollution-free welding in a vacuum. Therefore, it has important applications in high-tech fields such as aviation, aerospace, atomic energy, and electronics, as well as in the manufacture of some precision instruments. Robotic electron beam welding systems usually consist of electron beam generators, robot manipulators, control systems, vacuum systems, cooling systems, etc. Electron beam generators generate high-energy electron beams and use focusing devices to make the electron beams into fine beams. Robotic manipulators are used to carry electron beam guns to achieve precise welding positioning of workpieces and control of welding paths. The control system controls the power, current, speed and other parameters of the electron beam, as well as the robot’s motion trajectory, to ensure the stability of the welding process and the welding quality.
4 Welding quality control and inspection technology
4.1 Non-destructive testing
Non-destructive testing in welding quality control and inspection technology is a method to evaluate the internal defects and welding quality of welded joints without destroying the integrity of the sample. This technology provides inspection and evaluation of welding quality without affecting the performance of the welded structure. Using the principle of ultrasonic propagation in the material, ultrasonic waves are emitted and received by the probe to detect defects in welding, such as lack of fusion, inclusions, cracks, etc. Radiographic testing includes X-ray and gamma-ray testing, which analyze the internal quality of welding, such as pores, slag inclusions, and incomplete penetration, by the absorption and scattering of the rays after passing through the welded joint. After the welded joint is magnetized, magnetic powder is used to form magnetic marks at the defect, so as to find surface and near-surface defects such as cracks. Liquid penetrant is applied to the weld surface, and the penetrant will penetrate into the defect. Subsequently, the excess penetrant on the surface is absorbed by oil-absorbing paper, and then developed with a developer to find surface defects. Using the heat generated during welding and the temperature gradient of the joint, the temperature distribution image of the joint is captured by an infrared camera, and then the welding quality is analyzed. These non-destructive testing technologies have their own advantages and disadvantages, and often require professionals to operate and interpret the results. In actual welding quality control, appropriate testing methods or a combination of multiple methods can be selected according to the characteristics and requirements of the welded joint to improve the accuracy and reliability of the test.
4.2 Welding quality control methods
Welding quality control is a key process to ensure that welded joints meet design requirements and standards. It involves all stages from pre-welding to post-welding, including welding process planning, welding process monitoring, and detection of appearance and internal defects of welded joints. The welding process specification is a detailed document that describes the execution method of the welding task, including the materials used, welding methods, parameter settings (such as current, voltage, speed, etc.), environmental conditions, and operator requirements. Before the welding work begins, a pre-welding meeting is organized to ensure that all participants understand the requirements of the welding task and discuss potential risks and improvement measures. Ensure that the welding process meets standard requirements by real-time monitoring of welding parameters (such as current, voltage, speed, welding angle, etc.).
5 Application of welding technology in the automotive industry
Welding technology plays a vital role in the automotive industry. It is widely used in the manufacturing and maintenance of automobiles. In automobile body manufacturing, welding technology is used to connect various parts of the car body, such as doors, roofs, side panels, etc. Laser welding technology is particularly popular in modern automobile manufacturing due to its high precision, high efficiency and high-quality weld seams. Automobile structural parts, such as frames, suspension system components, engine brackets, etc., are usually manufactured using welding technology to ensure the strength and durability of the structure. In the manufacture of engines and other power system components, welding technology is used to manufacture high-quality metal structures, such as cylinder heads, cylinder blocks, exhaust pipes, etc. Robotic welding technology is usually used for welding of car seats to ensure the consistency and accuracy of welding. In the manufacture of safety components such as airbags and seat belts, welding technology is used to ensure that these components can work properly in accidents.
6 Conclusion
With the continuous advancement of science and technology and the continuous development of the automobile industry, advanced automobile body welding technology is also constantly evolving. In the future, automobile body welding technology will be more intelligent, more automated and more environmentally friendly. For example: using artificial intelligence and machine learning technology to achieve adaptive welding, make real-time adjustments according to different welding tasks, and improve production efficiency and welding quality. In general, advanced automobile body welding technology is an important driving force for the development of the automobile industry. It is not only related to the quality, performance and safety of automobiles, but also an important manifestation of the competitiveness of automobile manufacturers. In the future, continuous innovation in automobile body welding technology will bring more breakthroughs and developments to the automobile industry.
