Dual-Beam Laser Welding for Stable Molten Pools in Reflective Metals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Laser welding of high reflectivity metals like copper and aluminum faces challenges with sputter generation, leading to processing defects and metal material inefficiency due to excessive energy input, which increases the likelihood of voids and strength failures.
Innovation Solution
A welding method and apparatus that utilize a main beam with a higher power density and an auxiliary beam with lower power density, where the auxiliary beam is positioned anterior, posterior, or sideward to the main beam, overlapping partially to stabilize the molten pool and reduce sputter generation, using a diffractive optical element to shape the laser light profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-intensity laser light is used to compensate for high reflectivity during welding initiation, then welding can be started on high reflectivity metals, but excessive energy causes increased vaporized metal and disturbance of molten metal leading to sputter and void generation
Solution Approach 1:
The laser beam is segmented into multiple beams (first laser beam for keyhole formation, second laser beam for molten pool stabilization) with different power densities and positions. This segmentation allows each beam to perform its specific function without the harmful effects of excessive single-beam intensity, resolving the contradiction between needing high power to start welding and avoiding excessive energy that causes sputter.
Solution Approach 2:
Different regions of the laser beam are assigned different power densities - the first laser beam provides high power density for keyhole formation at the leading edge, while the second laser beam provides lower power density for stabilizing the molten pool at the trailing edge. This local quality differentiation enables effective welding initiation without the excessive energy input that causes sputter and voids.
2Power
If high-intensity laser light is used to compensate for high reflectivity, then welding can be performed on high reflectivity metals, but the excessive energy disturbs the molten metal and increases vaporized metal leading to voids and welding defects
Solution Approach 1:
The laser beam is divided into multiple beams with different power densities positioned at different locations. The first laser beam (higher power density) forms the keyhole, while the second laser beam (lower power density) stabilizes the molten pool and suppresses sputter. This segmentation enables welding of high reflectivity metals while maintaining high manufacturing precision by avoiding the excessive energy that causes voids and defects.
Solution Approach 2:
Different power densities are applied to different spatial regions of the weld zone. The high power density region creates the keyhole for deep penetration, while the lower power density region stabilizes the molten pool and prevents sputter. This local quality control achieves both effective welding of high reflectivity metals and high welding quality without voids.
3Device complexity
If high reflectivity metals are welded with conventional single-beam laser welding, then the process is simple, but sputter generation increases leading to processing defects and metal material loss
Solution Approach 1:
The laser welding system uses multiple segmented beams instead of a single beam. The first laser beam forms the keyhole while the second laser beam stabilizes the molten pool and suppresses sputter generation. This segmentation effectively reduces sputter and processing defects on high reflectivity metals, with the added complexity being justified by the significant improvement in welding quality and material utilization.
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
The method effectively suppresses sputter generation and stabilizes the molten pool, reducing defects and ensuring sufficient metal material for strong welds, even with high reflectivity materials.
Implementation Method 1
Laser welding is a welding method including irradiating a welding portion of a workpiece with laser light and melting the welding portion by energy of the laser light
Implementation Method 2
a diffractive optical element to shape the laser light profile
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3C
AI summary
A method for welding a workpiece includes steps of: disposing a workpiece in a region to be irradiated with laser light from a laser apparatus; and relatively moving the laser light and the workpiece so as to cause the laser light to sweep over the workpiece while irradiating the workpiece with the laser light from the laser apparatus, thereby melting and welding an irradiated portion of the workpiece. The laser light is formed of a main beam and an auxiliary beam, at least part of the auxiliary beam being disposed anteriorly in a sweep direction, and the main beam has a power density equal to or greater than a power density of the auxiliary beam.