Multi-Beam Laser Welding for Narrow Welds With Less Spatter
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Solution Overview
Problem
Laser welding methods face challenges in reducing spatter generation, which leads to insufficient metallic material at the weld portion, potentially causing poor strength and electrical circuit abnormalities, especially when welding smaller or thinner workpieces, where a smaller weld zone is required.
Innovation Solution
A welding method and apparatus that utilize a laser light with multiple beams, including a main beam and sub beams, where the sub beams are positioned ahead of or behind the main beams in the sweep direction, forming a main power region and a sub power region on the workpiece surface, with a minimum distance between beam centers set to 75 μm or less, to suppress spatter generation and narrow the weld zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the area of the weld zone is made smaller to weld smaller or thinner workpieces, then the suitability for small workpieces is improved, but spatter generation increases
Solution Approach 1:
The laser beam is divided into multiple beams (first, second, and third beams) with different positions and power levels. The first beam creates the main weld zone, while the second and third beams are positioned at the leading and trailing edges to control spatter generation through preheating and cooling effects, respectively
Solution Approach 2:
The second beam positioned at the leading edge of the weld zone performs preliminary heating of the workpiece before the main first beam arrives. This preheating reduces thermal shock and controls spatter generation by gradually preparing the material for melting
2Length of moving object
If the beam diameter is reduced to narrow the weld zone, then the weld zone width is improved, but spatter generation increases
Solution Approach 1:
Instead of using a single narrow beam, the invention uses multiple beams with different diameters and positions. The first beam has a smaller diameter for narrow weld zone, while the second and third beams with larger diameters control spatter at the edges, resolving the contradiction between narrow weld zone and spatter reduction
Solution Approach 2:
Different regions of the weld zone are treated with different beam characteristics. The center region uses the first beam for precise narrow welding, while the leading and trailing edges use the second and third beams with different power levels to locally control spatter generation and molten pool stability
3Adaptability or versatility
If laser welding is performed on small or thin workpieces, then the applicability to small workpieces is improved, but spatter generation increases causing material loss
Solution Approach 1:
The second beam positioned at the leading edge performs preliminary heating and prepares the material before the main first beam melts it. This gradual heating reduces abrupt vaporization and spatter generation, minimizing metallic material loss when welding small or thin workpieces
Solution Approach 2:
The third beam positioned at the trailing edge provides localized cooling and stabilizes the molten pool as it solidifies. This local control at the trailing edge prevents excessive spatter and material loss that would otherwise occur during rapid cooling of small workpieces
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 approach effectively reduces spatter generation and humping, ensuring a stable molten pool and improved weld quality by preheating the workpiece with sub beams before the main beams, resulting in a narrower weld zone and enhanced strength.
Implementation Method 1
irradiating a surface of a workpiece with a laser light that moves relatively to the workpiece in a sweep direction; and performing welding by melting a part of the workpiece irradiated with the laser light
Implementation Method 2
melting a part of the workpiece irradiated with the laser light by the energy of the laser light
Implementation Method 3
preheating the workpiece with sub beams before the main beams
Implementation Method 4
A pool of molten metal material called a molten pool is formed at the part irradiated with the laser light, and then the molten pool becomes solidified
Data Source
AI summary
A welding method includes: irradiating a surface of a workpiece with a laser light that moves relatively to the workpiece in a sweep direction; and performing welding by melting a part of the workpiece irradiated with the laser light. The laser light includes a plurality of beams, the plurality of beams include at least one main beam and at least one sub beam smaller in power than the main beam, a main power region including the at least one main beam and a sub power region including the at least one sub beam are formed on the surface, and a minimum distance between centers of adjacent ones of the plurality of beams on the surface is 75 μm or less.