Laser Lap Fillet Welding Path for Stable Joint Strength
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Solution Overview
Problem
Existing lap fillet welding techniques using laser-beam welding and MIG arc welding result in increased equipment size and complexity, compromising practicality and weld quality.
Innovation Solution
A laser-beam welding method where the laser beam is applied to metal plates along a circular or elliptical locus, first targeting the unmelted zone of one plate and then the other, ensuring sufficient heat transfer and preventing molten metal from being blown off due to keyhole pressure, thereby achieving a high-quality weld without the need for additional welding methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If composite welding including laser-beam welding and MIG arc welding is performed, then welding quality is improved, but equipment size and complexity increase
Solution Approach 1:
The patent merges the functions of laser-beam welding and MIG arc welding into a single integrated laser-beam welding system. The laser beam is applied in a specific pattern (first to one metal plate, then to the other metal plate in the overlap region) to achieve weld penetration and quality previously requiring composite welding, thereby eliminating the need for separate MIG welding equipment and reducing overall equipment complexity while maintaining welding quality
Solution Approach 2:
The welding process is segmented into distinct stages: first applying the laser beam to one metal plate to create initial melting and penetration, then applying it to the second metal plate in the overlap region. This segmented approach allows the single laser system to achieve the cumulative effect previously requiring two different welding methods, simplifying equipment while preserving weld integrity
2Reliability
If composite welding including laser-beam welding and MIG arc welding is performed, then welding quality is improved, but the size of welding equipment increases
Solution Approach 1:
The patent consolidates the equipment requirements for laser-beam welding and MIG arc welding into a single laser-beam welding apparatus. By applying the laser beam sequentially to different regions (first to one plate, then to the overlap region with the second plate), the system achieves deep penetration welds previously requiring composite welding equipment, thereby reducing the overall volume and footprint of the welding system
Solution Approach 2:
The laser-beam welding apparatus is designed to perform multiple functions: it can weld through the first metal plate and subsequently weld the second metal plate in the overlap region, effectively replacing what previously required two separate welding systems. This multi-functionality reduces equipment size by eliminating redundant welding apparatus while maintaining comprehensive welding capability
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 high-quality lap fillet welding with increased joint strength and reduced equipment complexity, eliminating the need for MIG arc welding, thus maintaining weld quality without enlarging or complicating the welding equipment.
Implementation Method 1
a laser beam is applied to a laser-beam application region including a portion of the first metal plate and a portion of the second metal plate
Implementation Method 2
ensuring sufficient heat transfer
Implementation Method 3
the metallic material is melted at the laser-beam application position
Implementation Method 4
the metallic material is melted at the laser-beam application position so that the first metal plate and the second metal plate are bridged
Data Source
Figure 1~2
Figure 3
Figure 4A~4D
AI summary
While a laser-beam application position is moved along a locus which circularly or elliptically circles around a locus center so as to cross a weld line (L) that is a boundary between a first metal plate (W1) and a second metal plate (W2) overlapped with each other, the locus center is moved in a direction parallel to a weld line (L). A moving direction of the laser-beam application position is set such that the laser beam is first applied to the first metal plate (W1) and then to the second metal plate (W2) when the laser beam passes through an unmelted zone of the first metal plate (W1) and the second metal plate (W2). The unmelted zone is located downstream of a range (X) through which the laser beam has already passed in the direction parallel to the weld line (L).