Friction Stir Welding Tool Groove Shoulder for Thickness Variation
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Solution Overview
Problem
Friction stir welding tools face challenges in maintaining consistent heat input and preventing welding defects due to variations in sheet thickness of work pieces, as existing methods struggle to adjust the gap between shoulder surfaces effectively, leading to uneven heat distribution and potential welding defects.
Innovation Solution
The friction stir welding tool incorporates a groove on at least one shoulder surface that extends radially outward, allowing excess thickness to be scraped and stirred, maintaining consistent contact areas and heat input, with the gap between shoulder surfaces fixed to account for thermal expansion, ensuring reliable welding even with varying sheet thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gap between shoulder surfaces is fixed to maintain consistent heat input, then welding reliability is improved, but the tool cannot adapt to variations in sheet thickness
Solution Approach 1:
The patent applies local quality by creating a groove at a specific location on the shoulder surface where material accumulation occurs. Instead of making the entire gap adjustable, only the groove region dynamically adapts to thickness variations while the rest of the fixed gap maintains consistent heat input. This localized feature allows the tool to handle thickness variations without compromising overall welding reliability.
Solution Approach 2:
The patent introduces dynamics by allowing the groove to dynamically accommodate varying material thickness during welding. As material accumulates in the groove due to thickness variations, the groove's geometry provides a dynamic response that maintains proper contact between shoulder surfaces and workpiece, enabling the fixed-gap tool to adapt to changing conditions.
2Adaptability or versatility
If the gap between shoulder surfaces is made adjustable to accommodate sheet thickness variation, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by designing the groove to automatically accommodate thickness variations without requiring external adjustment mechanisms. The groove's geometry allows it to self-adjust to different material thicknesses during welding, eliminating the need for complex adjustable gap mechanisms while maintaining adaptability to sheet thickness variation.
Solution Approach 2:
The patent extracts the adaptability function from the gap mechanism itself and relocates it to the groove feature on the shoulder surface. By separating the adaptation function from the gap structure, the patent eliminates the need for complex adjustable mechanisms while maintaining the ability to handle thickness variations.
3Manufacturing precision
If a tapered shoulder surface is used to suppress sheet thickness variation, then manufacturing precision is improved, but heat input becomes uneven leading to welding defects
Solution Approach 1:
The patent applies local quality by creating a groove at the specific location where material accumulation occurs on the shoulder surface. This localized feature allows the majority of the shoulder surface to maintain a uniform geometry that provides consistent heat input, while only the groove region adapts to thickness variations, preventing welding defects.
Solution Approach 2:
The patent segments the shoulder surface into two functional zones: a uniform region that provides consistent heat input and a grooved region that handles thickness variations. This segmentation allows the tool to simultaneously achieve uniform heat distribution and adaptability to thickness variations, preventing welding defects.
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 configuration allows for consistent heat input and effective welding by scraping excess material into the groove, preventing significant thickness reduction and ensuring satisfactory welding across varying sheet thickness ranges without the need for adjustable gaps, thus preventing defects and ensuring reliable friction stir welding.
Implementation Method 1
a tool is rotated while a surface called a shoulder surface of the tool is pressed against a welding position of the work piece with a predetermined pressure so as to generate friction heat in the surface of the work piece
Data Source
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AI summary
The present application relates to a method of friction stir welding using a tool comprising a first shoulder surface (32) which comes into contact with a front surface of a subject work piece (w), a second shoulder surface (35) which is disposed so as to face the first shoulder surface (32) and comes into contact with a rear surface of the work piece (w) and a shaft portion (37) which connects the first shoulder surface (32) and the second shoulder surface (35) to each other with a gap therebetween fixed, the first shoulder surface (32) and the second shoulder surface (35) are provided with a first vortex groove (33) and a second vortex groove (36) which extend toward the front side of a tool rotation direction (R) so as to be opened to the outer peripheral edge as it moves to the outer peripheral side.