Application of Beam Shaping Technology in Laser Welding

01 Introduction

The application of beam shaping technology in laser welding is becoming increasingly widespread. By optimizing laser energy distribution, this technology improves melt pool stability and reduces welding defects, making it one of the key techniques in high-end manufacturing. While the traditional Gaussian beam is suitable for various materials, its high central energy density often leads to overheating, spattering, and unstable keyholes. Beam shaping techniques, such as adjusting beam profiles (e.g., ring, elliptical, or flat-top beams) or dynamically modulating energy distribution (e.g., galvanometer scanning, multi-beam superposition), optimize the welding process window and enhance weld quality. Depending on the application method, beam shaping can be classified into three main categories: static beam shaping, dynamic beam shaping, and multi-beam modes, each with unique principles, advantages, and applicable scenarios.

02 Static Beam Shaping

Static beam shaping modifies the spatial energy distribution of the laser using diffractive optical elements (DOE), aspherical lenses, or fiber mode conversion to generate specific beam profiles such as flat-top, ring, or elliptical beams. For example, in copper and aluminum alloy welding, a ring-shaped beam can reduce high reflectivity effects, improve energy coupling efficiency, and enhance keyhole stability. Experiments have shown that, compared to traditional Gaussian beams, the penetration depth fluctuation of aluminum alloy welding using a ring-shaped beam is reduced by 30%, and spatter is decreased by 50%. Additionally, in dissimilar material welding (e.g., copper-stainless steel), elliptical beams optimize heat input matching and reduce crack sensitivity, making them widely used in electric vehicle battery connections.

03 Aluminum-Aluminum Welding

In the study of butt joints between 3mm-thick aluminum alloys 2A12-T4 and 6061-T6 (laser power: 3400W, welding speed: 50mm/s, oscillation frequency range: 0-500Hz, amplitude range: 0.4-1.6mm), it was observed that the copper content in the base materials varies (approximately 4.9% for 2A12 and 0.15% for 6061). Achieving ultra-high-strength welded joints requires uniform distribution of copper within the melt pool. As shown in Figure 2, in traditional laser welding, copper tends to migrate toward the 2A12 aluminum alloy. However, in oscillating laser welding, the oscillation of the laser beam and the turbulence of the melt pool help push copper from the high-copper 2A12 alloy to the lower-copper 6061 alloy, promoting uniform copper distribution and enhancing weld strength.

04 Aluminum-Stainless Steel Welding

In oscillating laser welding of stainless steel and 6061 aluminum alloy, different oscillation amplitudes were tested. Experimental results indicate that increasing the oscillation amplitude improves the performance of Al/steel dissimilar joints. According to temperature field simulations of the melt pool, oscillating laser beams disperse laser energy, and the diffusion of heat reduces interface element diffusion and aluminum substrate melting. As a result, the formation of intermetallic compounds (IMCs) is suppressed, leading to improved tensile shear performance of the welded joints.

05 Conclusion

Oscillating laser welding, through high-frequency beam oscillation and dynamic heat input control, significantly enhances the welding quality of aluminum and dissimilar metal joints. In aluminum-copper welding, it suppresses the formation of brittle IMCs. In aluminum-aluminum welding, it ensures uniform copper distribution in the melt pool through laser oscillation and turbulence, thereby improving weld strength. In aluminum-steel welding, it disperses energy to reduce interface element diffusion, greatly enhancing tensile load capacity. This technology, with its precise heat input control, defect suppression, and microstructure optimization, has become a key process in demanding applications such as electric vehicle batteries and lightweight aerospace structures, ensuring both efficiency and reliability.

**--Cite the article published by 高能束加工技术 on March 25, 2025, in the WeChat public account "High-Energy Beam Processing Technology and Applications."