Core-Ring Laser Beam Shaping for Spatter-Free Corner Welding
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Solution Overview
Problem
Existing laser welding methods for corner joins of workpieces often result in instabilities such as pores and spatters due to excess pressure in vapor capillaries, leading to poor weld quality and increased risk of short circuiting, especially in the production of battery housings.
Innovation Solution
The method employs a multiclad fiber with both a core and ring fiber to shape the laser beam, where a portion of the laser power is fed into the core fiber and another portion into the ring fiber, creating a beam profile that minimizes spatter formation by facilitating gas escape and reducing pressure in vapor capillaries, resulting in deep, stable welds with high gas tightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional laser welding methods are used for corner joins, then welding can be performed, but instabilities such as pores and spatters are produced due to excess pressure in vapor capillaries
Solution Approach 1:
The laser beam is segmented into multiple independent beam paths using a multiclad fiber with a core fiber and ring fiber. This segmentation allows different regions of the beam to be independently controlled, enabling the ring beam to facilitate gas escape while the core beam provides primary welding energy, thereby reducing spatter and pore formation
Solution Approach 2:
The multiclad fiber acts as an intermediary device that transforms a conventional single-mode laser beam into a structured beam with core and ring components. This intermediary structure enables the laser beam to interact with the workpiece in a controlled manner that reduces vapor capillary pressure and minimizes harmful spatter ejection
2Productivity
If higher laser power is used to improve welding speed, then productivity increases, but spatter formation and instability increase
Solution Approach 1:
Different regions of the laser beam are assigned different functions: the ring fiber region facilitates gas escape and pressure relief, while the core fiber region provides concentrated welding energy. This local differentiation allows high power welding speeds without proportionally increasing spatter, as the ring beam locally manages the harmful pressure effects
3Reliability
If conventional single-mode laser beams are used, then device complexity is low, but weld stability and gas tightness are poor
Solution Approach 1:
The multiclad fiber serves as an intermediary component that encapsulates the beam shaping complexity within a single replaceable element. Rather than requiring complex external optical systems, the fiber itself performs the beam transformation from single-mode to structured multi-region output, simplifying the overall device architecture while achieving superior weld quality
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 advancement speeds, producing smooth welds with high stability and gas tightness, suitable for battery housing manufacturing.
Implementation Method 1
generating a laser beam having a beam profile
Implementation Method 2
The laser welding system comprises beam-shaping means, for example optical elements for diffraction of the laser beam
Implementation Method 3
instabilities, for example in the form of pores, may be produced in the workpiece and eject spatters of the molten material
Data Source
AI summary
A method for laser welding of a workpiece includes welding at a corner joint of two workpiece parts of the workpiece by a welding laser beam to create an aluminum connection between the two workpiece parts, and feeding an output laser beam into a first end of a multiclad fiber to generate the welding laser beam. The multiclad fiber comprises at least a core fiber and a ring fiber surrounding the core fiber. A first portion LK of a laser power output of the output laser beam is fed into the core fiber, and a second portion LR of the laser power output of the output laser beam is fed into the ring fiber. A second end of the multiclad fiber is reproduced on the workpiece. The method further includes welding the workpiece by deep welding.