Laser Welding Process Improves Automotive Body Manufacturing

Gestamp, in collaboration with TRUMPF, has developed an industrial laser welding process designed to address the challenges of joining large, coated structural components in automotive manufacturing. The process improves welding speed, seam quality, and production efficiency, particularly for press-hardened steels used in modern vehicle body structures.

Shift Toward Large Structural Components
Automotive manufacturers are increasingly adopting large-format structural components to reduce assembly complexity and improve production efficiency. Gestamp’s Ges-Gigastamping^® approach uses hot-formed, high-strength steel parts to enhance crash performance while reducing the number of individual components.

However, these materials—typically coated with aluminum-silicon (AlSi) for corrosion protection—pose challenges for conventional joining methods. The coating interferes with weld integrity, making traditional spot welding less effective and limiting process flexibility.

Laser Welding Challenges with Coated Steels
Gestamp initially developed the G-Weld process, featuring a G-shaped overlap seam optimized for joining large components. While this approach enabled welding speeds up to five times higher than conventional methods, it required prior removal of the AlSi coating to ensure weld quality.

This additional step reduced overall process efficiency, offsetting the benefits of faster welding. The challenge was to achieve consistent, high-quality welds without removing the protective coating.

Multifocus Laser Beam Shaping
The solution was developed using TRUMPF’s multifocus laser beam shaping technology. This approach divides the laser into four individual beams, each delivering controlled energy input with both core and ring beam components.

The ring beam stabilizes the melt pool, reducing spatter formation, while the multiple beams ensure homogeneous mixing of the AlSi coating during welding. This controlled interaction prevents the formation of brittle intermetallic phases and alpha ferrite, which can degrade mechanical properties.

As a result, the process produces stable weld seams with high tensile strength and improved structural integrity, even when joining coated materials.

Performance Gains and Manufacturing Benefits
The optimized process enables significantly higher welding speeds while maintaining consistent seam quality. Improved accessibility allows welding of large structural components without reducing process speed, supporting efficient production of complex geometries.

Single-sided laser welding also creates a “semi-visible surface,” where weld seams are not externally visible, improving the aesthetic and functional quality of finished components.

By eliminating the need for pre-processing steps such as coating removal, the process reduces production time and simplifies workflow, contributing to a more efficient digital supply chain in automotive manufacturing.

Relevance for Electric and Lightweight Vehicle Design
The ability to reliably join high-strength, lightweight materials is critical for electric vehicles and next-generation automotive platforms. Structural components must meet strict requirements for strength, weight reduction, and manufacturability.

The new laser welding process supports these objectives by enabling efficient production of large, integrated components with consistent quality. This contributes to reduced vehicle weight, improved crash performance, and streamlined assembly processes.

Edited by Romila DSilva, Induportals Editor, with AI assistance.