What is laser welding?
In simple terms, laser welding is a welding method that uses laser radiation to heat the surface of the workpiece. The surface heat is then diffused into the interior through heat conduction. By controlling parameters such as the width, energy, peak power, and repetition rate of the laser pulse, the workpiece is melted, forming a specific molten pool, thus achieving welding.
Laser welding has the following characteristics:
- It can minimize the input heat, reduce the range of microstructural changes in the heat-affected zone, and minimize deformation.
- It is a non-contact welding method, minimizing tool wear and deformation.
- The laser beam is easy to focus and align, suitable for welding small and closely spaced parts.
- It can weld various dissimilar materials, with a wide range of types.
- It is easy to automate for high-speed welding and can also be digitally or computer controlled.
- When welding thin sheets or fine wire, problems such as re-melting are avoided.
How does laser welding work?
The working principle of laser welding mainly involves exciting laser active media (such as CO2 and other gas mixtures, YAG yttrium aluminum garnet crystals, etc.) to oscillate back and forth in the resonant cavity, forming a stimulated emission beam. When this beam contacts the workpiece, its energy is absorbed by the workpiece. As the absorbed energy of the workpiece reaches the melting point of the material, the welding process begins.
Laser welding can be divided into two modes: conduction welding and deep penetration welding.
In conduction welding, laser radiation heats the surface to be processed, and the surface heat diffuses inward through heat conduction. By controlling the width, energy, peak power, and repetition rate of laser pulses, the workpiece is melted, forming a specific weld pool.
In deep penetration welding, laser with sufficiently high power density vaporizes the material and forms small holes. These small holes absorb almost all incident beam energy like a blackbody, allowing heat to transfer from the outer wall of the high-temperature cavity to melt the metal around the cavity. Eventually, as the beam moves, molten metal fills the gap left after the removal of the filled small hole, which then solidifies to form the weld seam.
Advantages of laser welding
The advantages of laser welding mainly manifest in the following aspects:
High Energy Density and Efficiency:
The energy density of the laser beam is extremely high, enabling a large amount of energy to be concentrated in a small area in a short period. This allows for rapid heating and melting of materials, achieving high-speed and efficient welding. This is particularly advantageous for large-scale, high-speed production lines.
High Welding Quality:
Laser welding produces well-formed, stable-sized weld seams with few defects, large welding depth, and minimal deformation. Due to the small heat-affected zone of laser welding, the stresses and deformations generated during welding are also small, ensuring the quality and performance of the welded joint.
Wide Applicability:
Laser welding technology can be applied to welding various materials, including metals, plastics, ceramics, and even dissimilar materials, demonstrating high flexibility.
High Automation:
Laser welding is easily automated and can be operated without human intervention. It can be integrated with robotic and other automated equipment to further increase production efficiency. Moreover, laser welding is non-contact, allowing welding to be performed without contacting the workpiece, which is advantageous for components that are difficult to access or susceptible to damage.
Disadvantages of laser welding
Although laser welding offers numerous advantages, it also comes with several drawbacks. Here’s a detailed analysis of the disadvantages of laser welding:
High Equipment Costs:
Laser welding machines and associated equipment typically come with high price tags, primarily due to the high manufacturing and maintenance costs of lasers. For many small businesses, this could be a significant financial burden, limiting the widespread adoption of laser welding technology.
High Skill Requirements:
Laser welding demands operators to possess high levels of technical proficiency and extensive experience. Due to the limited focus range of the laser beam, precise workpiece positioning is essential to avoid welding defects such as welding undercut, spattering, cracks, and porosity. These defects not only affect the appearance quality of the weld but may also compromise its mechanical properties and service life. Additionally, precise control of parameters such as laser power and welding speed is crucial during the laser welding process, requiring operators to have advanced skills.
High Precision Assembly Requirements:
Laser welding necessitates precise assembly and positioning of workpieces before welding. Insufficient precision in workpiece assembly may result in the laser beam failing to accurately focus on the welding area, thereby affecting welding quality.
Limited Material Adaptability:
While laser welding can be applied to various materials, the welding performance on certain materials, such as highly reflective materials, may be suboptimal. Moreover, for thicker workpieces, laser welding may require longer welding times and higher energy input.
Conclusion
When choosing whether to use laser welding technology, understanding the advantages and disadvantages of laser welding will help you make the best choice for your project. In addition, BoYi is a company certified by ISO 9001:2015, and you can be confident that their technology is industry-leading. You can contact BoYi at any time to obtain laser welding services.
