Multiclad Fiber Laser Welding for Stable Aluminum Corner Seams
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Solution Overview
Problem
Existing laser welding methods for corner connections of workpieces, particularly in battery housings, often result in instabilities such as pores and splashes of molten metal due to excess pressure in steam capillaries, leading to spatter formation and reduced weld quality.
Innovation Solution
A laser welding process using a multiclad fiber to shape the laser beam, with power divided between a core and ring fiber, which influences vapor capillary shape and melt pool dynamics, minimizing spatter formation by facilitating gas escape and reducing pressure within the capillary, resulting in a stable I-seam weld with high gas-tightness and smooth seam surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional laser welding methods are used for corner connections, then welding can be performed on aluminum workpiece parts, but instabilities such as pores and splashes of molten metal occur due to excess pressure in steam capillaries
Solution Approach 1:
The patent applies parameter changes by modifying the beam profile parameters through multiclad fiber coupling. The laser beam is divided into different propagation modes (core mode and cladding modes) with specific power distributions, changing the intensity distribution parameters to achieve stable welding without spatter. The core mode provides deep penetration while the cladding modes control the vapor capillary pressure, resolving the contradiction between weld stability and spatter formation.
Solution Approach 2:
The patent implements local quality by creating different beam intensity characteristics in different regions of the weld zone. The core fiber delivers high intensity for deep penetration at the center, while the ring fiber delivers lower intensity for controlling the vapor capillary pressure at the periphery. This local differentiation of beam quality enables stable welding without spatter by addressing different zones of the melt pool with appropriate energy distributions.
2Manufacturing precision
If conventional beam profiles are used, then welding process is simple, but weld seams exhibit rough surfaces and reduced gas tightness
Solution Approach 1:
The patent replaces complex mechanical beam shaping systems with an optical fiber-based solution. Instead of using mechanical optics components (lenses, mirrors, apertures) to shape the beam profile, the invention uses the intrinsic modal properties of the multiclad fiber to automatically generate the desired beam structure. This substitution achieves high weld seam quality with reduced mechanical complexity.
Solution Approach 2:
The multiclad fiber structure provides self-service by automatically generating the optimal beam profile through its built-in modal characteristics. The fiber's core-cladding structure inherently separates the beam into different propagation modes with appropriate intensity distributions, eliminating the need for external beam shaping components. This self-organizing property achieves high precision welding while minimizing system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces spatter formation by up to 90% and allows for higher feed speeds, achieving stable and smooth welds with increased durability and sealing integrity, suitable for battery housing production.
Implementation Method 1
an output laser beam is fed into a first end of a multiclad fiber... a first part LK of the laser power of the output laser beam is fed into the core fiber and a second part LR of the laser power of the output laser beam is fed into the ring fiber
Implementation Method 2
the laser welding of the workpiece is carried out by deep penetration welding
Implementation Method 3
In the deep penetration welding regime, lasers with a comparatively high power density are used, which causes the laser to generate vapor during welding
Data Source
Figure 1a
Figure 1b~1c
Figure 1d~1e
AI summary
A method for the laser welding of a workpiece (1, 1b), wherein a welding laser beam (11) is used to weld an I-seam (8, 8b) at the corner joint (2a) of two workpiece parts (3a, 3b) of the workpiece (1, 1b), as a result of which an aluminum connection between the workpiece parts (3a, 3b) is produced, wherein in order to generate the welding laser beam (11) an output laser beam is fed into a first end of a multi-clad fiber, in particular of a 2-in-1 fiber, wherein the multi-clad fiber comprises at least one core fiber and a ring fiber surrounding the latter, wherein a first portion LK of the laser power of the output laser beam is fed into the core fiber and a second portion LR of the laser power of the output laser beam is fed into the ring fiber, wherein a second end of the multi-clad fiber is projected onto the workpiece, and wherein the laser welding of the workpiece is effected by deep welding. The method produces particularly stable corner connections of workpiece parts while avoiding spatter.