Laser Welding with a Through-Hole Interlayer for Mixed Metals
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Solution Overview
Problem
Conventional spot welding methods are inefficient for joining different-type materials like steel and aluminum, requiring complex rivet designs, long processing times, and limited flexibility in product shape due to the need for precise positioning and pressure application, which hampers productivity and joint stiffness.
Innovation Solution
A laser welding method that uses a third material with a through-hole to facilitate the joining of first and second materials by emitting laser light between them, with specific gap configurations to ensure effective welding and compressive fixation, allowing for various welding traces such as circular, spiral, or coiled shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If spot welding is used to join different-type materials (steel and aluminum), then joint strength can be achieved, but the welding time is excessively long and productivity is reduced
Solution Approach 1:
A third material layer is introduced as an intermediary between the first and second different-type materials. This intermediate layer facilitates laser welding by enabling proper heat distribution and weld formation, allowing direct welding of materials that would otherwise be difficult to join, thereby reducing welding time while maintaining joint strength
Solution Approach 2:
The invention controls the thickness of the third material layer within specific ranges (0.1-1.0mm preferably) to optimize heat conduction and weld formation. By adjusting this parameter, the welding process achieves both strong joints and reduced welding time, resolving the contradiction between joint strength and productivity
2Strength
If complex rivet designs with chamfered edges and annular grooves are used to connect different-type materials, then joint strength is maintained, but manufacturing complexity and production cost increase
Solution Approach 1:
The invention extracts the complex geometric features (chamfered edges, annular grooves) from the rivet structure and replaces them with a simpler third material layer that achieves the same functional outcome of maintaining joint strength between different-type materials, thereby reducing manufacturing complexity
Solution Approach 2:
The mechanical complex rivet structure is replaced with a material-based solution (third material layer) that uses material properties and controlled thickness to achieve joint strength, substituting mechanical complexity with material science-based simplicity
3Ease of manufacture
If spot welding is used with electrodes requiring pressure application, then welding can be performed, but the welding gun requires significant space and limits product shape flexibility
Solution Approach 1:
The mechanical pressure-application system (electrodes and welding gun) is replaced with a laser-based welding system that uses optical energy to join materials. This substitution eliminates the need for physical contact and pressure application, allowing welding in confined spaces and on complex product shapes
4Reliability
If rivets are disposed with minimum joining pitch to avoid branch current, then sufficient nugget formation is achieved, but joint stiffness at intended positions is reduced
Solution Approach 1:
The invention changes the critical parameter from rivet spacing (joining pitch) to third material layer thickness. By controlling the thickness of the intermediate layer within specific ranges, the system achieves both sufficient weld quality and appropriate joint stiffness without being constrained by minimum spacing requirements
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 method significantly reduces production time, enhances joint stiffness, and increases design flexibility by compressively fixing the third material between the weldable first and second materials, overcoming the limitations of spot welding and achieving strong, defect-free welds.
Implementation Method 1
a welding method comprising: a step of emitting a laser beam toward a welding position, while a third material is sandwiched between a first material and a second material, so that the first material and the second material are welded via a through-hole part of the third material
Implementation Method 2
In laser welding, molten metal is solidified into a weld nugget at a welding position
Implementation Method 3
In laser welding, molten metal is solidified into a weld nugget at a welding position
Data Source
AI summary
A laser welding method according to the present disclosure includes a step in which a third material is interposed between a first material and a second material, which are made of the same type of metal so as to be weldable to one another, and at least one of which is provided with a protruding portion, wherein the third material is difficult to weld to the first material and the second material and has a through-hole portion into which the protruding portion is inserted. The method also includes a step in which, when the third material is interposed between the first material and the second material, a region corresponding to the protruding portion is irradiated with a laser beam from the first material side, and the first material and the second material are welded via the through-hole portion. In the step in which the third material is interposed between the first material and the second material, a first gap is provided between the protruding portion and the inner peripheral face of the through-hole portion, and a second gap corresponding to the plate thickness of the first material is provided between the first material and the second material in the region corresponding to the protruding portion.