Laser Welding of Laminated Metal Foils Without Blowholes or Spatter
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Solution Overview
Problem
The existing method of welding laminated metal foils between metal plates using keyhole welding often results in blowholes and spatter, which can adversely affect the fatigue strength and electrical resistance of the welded part, and heat conduction welding alone struggles to form a sufficient molten pool for bonding due to heat escape in high thermal conductivity materials like aluminum or copper.
Innovation Solution
A method involving laser welding where a hole is formed in the upper metal plate with a chamfered edge, allowing the laser beam to create a molten pool that expands and agitates to reach the lower plate, effectively preventing blowholes and spatter by projecting the laser beam in a circular motion for heat conduction welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If keyhole welding is performed to form a molten pool for bonding metal plates to laminated metal foils, then the bonding strength is improved, but blowholes and spatter are generated which adversely affect the welded part quality
Solution Approach 1:
The welding process is divided into two distinct stages: first heat conduction welding to form a controlled molten pool without keyhole, then keyhole welding to achieve penetration and strong bonding. This segmentation allows each stage to optimize for its specific function, preventing blowholes during molten pool formation while still achieving strong bonding through the subsequent keyhole welding stage.
Solution Approach 2:
Heat conduction welding is performed as a preliminary action before keyhole welding to create an initial molten pool with controlled characteristics. This preliminary molten pool serves as a foundation for the subsequent keyhole welding, ensuring that the molten pool is properly formed and positioned before penetration welding begins, thereby preventing blowhole formation.
2Object-generated harmful factors
If heat conduction welding is used to prevent blowholes and spatter, then the welded part quality is improved, but the molten pool cannot grow sufficiently to reach the lower metal plate due to heat escape in high thermal conductivity materials
Solution Approach 1:
The welding process is divided into two distinct stages: first heat conduction welding to form a controlled molten pool without keyhole, then keyhole welding to achieve penetration and strong bonding. This segmentation allows each stage to optimize for its specific function, preventing blowholes during molten pool formation while still achieving strong bonding through the subsequent keyhole welding stage.
Solution Approach 2:
The welding process continues from heat conduction welding into keyhole welding without interruption. The molten pool formed during heat conduction welding serves as the starting point for keyhole welding, maintaining continuous heating and molten pool development. This continuity ensures that the molten pool grows sufficiently to reach the lower metal plate while maintaining the quality benefits of heat conduction welding.
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 allows for the formation of a necessary molten pool for bonding while significantly reducing blowholes and spatter, enhancing the quality of the welded part and improving the bonding process for laminated metal foils made of high thermal conductivity materials.
Implementation Method 1
projecting the laser beam for heat conduction welding onto the chamfered part of the upper metal plate to form a molten pool
Implementation Method 2
projecting the laser beam in a circle to agitate the molten pool and grow the molten pool in a laminating direction of the laminated metal foils
Implementation Method 3
laser-welding the laminated metal foils to the upper metal plate and the lower metal plate
Data Source
AI summary
A method of welding laminated metal foils (LMF) by projecting a laser beam onto LMF sandwiched between an upper metal plate and a lower metal plate from a side of the upper metal plate and laser-welding the LMF to the upper metal plate and the lower metal plate. The method includes: forming a hole in an upper surface of the upper metal plate and forming a chamfered part so that a diameter of the hole expands toward the upper surface before the laser welding; and in the laser welding, projecting the laser beam for heat conduction welding onto the chamfered part of the upper metal plate to form a molten pool; and projecting the laser beam in a circle to agitate the molten pool and grow the molten pool in a laminating direction of the LMF so that the molten pool reaches the lower metal plate.