Polygonal Torch Weaving for One-Pass Fillet Weld Penetration
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Solution Overview
Problem
Existing fillet welding techniques face challenges in achieving long leg lengths with good bead appearance and weldability while preventing defects like lack of penetration, undercut, and overlap, especially in automation and various welding postures like downward and vertical fillet welding, using a single electrode and one-pass welding.
Innovation Solution
A weaving control method that sets a welding torch position with a weaving reference line passing through a base point on the weld line, using at least five fixed end points on both sides, with specific distance and speed conditions to form a polygon trajectory, allowing the torch to move between these points to maintain penetration and prevent defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If one-pass welding is used to achieve long leg length, then welding efficiency is improved, but penetration of root portion and prevention of weld defects becomes difficult
Solution Approach 1:
The welding process is segmented into multiple stages with different weaving patterns: a first stage with a first weaving pattern for root portion penetration, and a second stage with a second weaving pattern for bead appearance. This segmentation allows each stage to optimize for its specific function, resolving the contradiction between efficiency and penetration quality.
Solution Approach 2:
The weaving pattern is made dynamic by switching between different patterns during the welding process. The weaving control unit changes the weaving pattern from the first pattern to the second pattern based on welding progress, allowing the system to adapt to different welding requirements at different stages and achieve both penetration and bead quality in one pass.
2Ease of operation
If a single electrode is used for automation, then ease of operation is improved, but achieving good bead appearance and preventing defects becomes difficult
Solution Approach 1:
The system uses dynamic switching of weaving patterns controlled by a weaving control unit to achieve different welding outcomes at different stages. This allows a single electrode to perform multiple functions (penetration and bead formation) by changing its motion pattern, maintaining automation while achieving high precision bead appearance.
Solution Approach 2:
The weaving operation uses periodic motion patterns that are switched between two distinct patterns. The first weaving pattern operates periodically for root penetration, then switches to a second periodic pattern for bead appearance, allowing the single electrode to achieve both objectives through timed periodic actions.
3Productivity
If flux-cored wire is used to achieve large leg length, then productivity is improved, but penetration of root portion and prevention of slag entrainment becomes difficult
Solution Approach 1:
The welding process segments the function of the flux-cored wire by using different weaving patterns at different stages. In the first stage, the wire benefits from flux properties for rapid deposition, while in the second stage, the weaving pattern adjusts to ensure proper penetration and slag control, allowing productivity gains without sacrificing reliability.
Solution Approach 2:
The system changes the weaving pattern parameter dynamically during welding. This parameter change allows the flux-cored wire to operate optimally for high-speed deposition in the first stage, then transitions to a pattern that ensures proper penetration and slag control in the second stage, resolving the contradiction between productivity and reliability.
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 enables efficient one-pass welding with a single electrode, achieving good bead appearance and weldability while preventing weld defects, and can be applied to various fillet welding postures, enhancing automation efficiency.
Implementation Method 1
Gas shielded arc welding is generally applied as the fillet welding
Data Source
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AI summary
To have excellent bead external appearance and welding workability while maintaining efficiency, and to prevent inferior merging and welding defects. A weaving control method for performing welding along a prescribed weld line while causing a welding torch (11) to swing by a weaving operation in fillet welding of two materials to be welded, wherein: in a plane perpendicular to a welding advancement direction (X), the position of the welding torch (11) is set and five or more fixed end points are set so that a weaving reference line (L3) passes through a reference point on the weld line, the weaving reference line (L3) being a center line at an initial position of the weaving operation; one or more of the fixed end points are provided to each of the two ends of the weaving reference line (L3), and the fixed end points are positioned so that there is provided a reference end point (a) at which the distance between a tip and a parent material is shortest and which is on the weaving reference line (L3); and the weaving operation moves between the fixed end points so that, as viewed from the welding advancement direction (X), the welding torch (11) follows a trajectory forming a polygonal shape.