Dual-Beam Laser Welding Layout for Splash-Free Full Penetration
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Solution Overview
Problem
Laser beam welding with high feed speeds often results in reduced weld seam quality due to spatter formation and increased weld pool dynamics, particularly when using solid-state lasers for deep or full penetration welds, and existing methods to mitigate these issues are not effective for achieving high-quality welds on both the top and bottom sides of the seam.
Innovation Solution
A method involving the use of a first beam area generated by a first laser beam and a second beam area generated by a second laser beam, where the centroids do not coincide, with the first beam area running ahead and having a greater length, width, and surface area than the second beam area, and the second laser beam is irradiated into the weld pool formed by the first beam, allowing for low energy input and minimized spatter formation on the bottom side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high feed speed is used in laser beam welding, then productivity is improved, but weld seam quality deteriorates due to spatter formation and increased weld pool dynamics
Solution Approach 1:
The laser beam is divided into multiple partial beams with different focus diameters and power densities. A first partial beam with larger focus diameter creates a broader weld pool, while a second partial beam with smaller focus diameter concentrates energy to maintain stable keyhole formation, reducing spatter even at high feed speeds
Solution Approach 2:
Different regions of the weld pool are subjected to different energy densities. The center region receives concentrated energy from the smaller focus beam to maintain keyhole stability, while the peripheral regions receive distributed energy from the larger focus beam, creating optimal local conditions for preventing spatter formation
2Use of energy by moving object
If solid-state laser with high power density is used, then energy efficiency is improved, but weld pool dynamics increase leading to more spatter and reduced seam quality
Solution Approach 1:
The high power density solid-state laser beam is segmented into multiple partial beams with different focus characteristics. This segmentation allows the energy to be distributed in a controlled manner, preventing excessive local heating and turbulent melt flow that causes spatter, while maintaining overall energy efficiency
Solution Approach 2:
The patent changes the parameters of the laser beam by creating multiple focus areas with different diameters and power densities. The first partial beam has larger focus diameter and lower power density, while the second partial beam has smaller focus diameter and higher power density, optimizing the balance between energy efficiency and spatter reduction
3Manufacturing precision
If CO2 laser is used for full penetration welding, then weld seam quality is maintained, but energy costs increase
Solution Approach 1:
The patent changes the fundamental parameters of the laser system by using solid-state lasers with different focus characteristics instead of CO2 lasers. By optimizing the combination of two partial beams with different focus diameters, the process achieves full penetration welding with high seam quality while utilizing the higher energy efficiency of solid-state laser technology
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
Enables high-quality full penetration welding with low weld pool dynamics and minimized spatter on both the top and bottom sides of the seam, even at high feed speeds, by maintaining the vapor capillary closed on the underside of the workpiece, thus achieving good seam quality without subsequent machining.
Implementation Method 1
generating at least a first beam area (4) on the workpiece (3) by a first laser beam (1)
Implementation Method 2
generating a second beam area (5) on the workpiece (3) by a second laser beam (2)
Implementation Method 3
the relative movement between the laser beam and the workpiece moves a vapor capillary (keyhole) through the liquid weld pool
Data Source
AI summary
Laser beam welding a workpiece includes: generating first and second beam areas on the workpiece by first and second laser beams, respectively. The beam areas are guided in a feed direction relative to the workpiece. Centroids of the beam areas are not coinciding. The first beam area runs ahead of the second beam area. A length of the first beam area, measured transversely to the feed direction, is greater than or equal to that of the second. A surface area of the first beam area is greater than that of the second. A width of the first beam area, measured in the feed direction, is greater than or equal to that of the second. A laser power of the first laser beam is greater than that of the second. The second laser beam is irradiated into a weld pool generated by the first laser beam.