Friction Stir Welding at Edge Portions Using End-Face Pressing
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Solution Overview
Problem
Friction stir welding at edge portions often results in defective joints due to deformation and gap formation caused by the squeezing out of softened material between the edge portions of the works, leading to poor weld quality.
Innovation Solution
A friction stir welder and method that includes a stage for mounting material pieces, a pressing member to cover and press the end faces of the pieces, and a rotary tool inserted while rotating to generate plastic flow at the interfacing portion, preventing deformation and ensuring firm contact between edge portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If friction stir welding is performed at edge portions of works, then welding capability at edge portions is improved, but deformation and gaps occur due to squeezed-out softened material
Solution Approach 1:
A pressing member is introduced as an intermediary element between the rotary tool and the workpiece edge portions. This pressing member applies controlled pressure to prevent the squeezed-out softened material from causing deformation and gaps, thereby enabling high-quality welding at edge portions that was previously difficult to achieve
2Length of moving object
If the distance between the rotary tool and end faces of the works is small, then welding at edge portions is enabled, but defective joints occur due to squeezed-out material
Solution Approach 1:
The pressing member applies preliminary counter-pressure to the workpiece edge portions before and during the welding process. This preliminary anti-action prevents the harmful effect of squeezed-out softened material that would otherwise cause deformation and defective joints when welding at edge portions with small distances
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 prevents the formation of defects like burrs and gaps between edge portions, resulting in high-quality welding by maintaining firm contact and minimizing the gap between the edge portions, thus enhancing the weld quality.
Implementation Method 1
a portion of the upper work becomes heated and softened due to a friction with the pin of the rotary tool
Implementation Method 2
friction stir welding is performed in such a manner that a pair of works (material pieces to be welded) that are mounted and stacked one on the other on a stage and a rotary tool rotating at high speed is pressed into the works
Implementation Method 3
a pressing member that covers and presses end faces of the material pieces to be welded that are mounted and stacked on the stage
Implementation Method 4
a plastic flow is generated at an interfacing portion as well as in a vicinity thereof between the rotary tool and the material pieces to be welded, thereby to joint the material pieces to be welded to each other
Data Source
AI summary
The present invention provides a friction stir welder that includes a stage on which at least two material pieces to be welded are mounted and stacked, a pressing member that covers and presses end faces of the material pieces to be welded that are mounted and stacked on the stage, and a rotary tool that is inserted into the stacked material pieces to be welded while rotating, so that a plastic flow is generated at an interfacing portion as well as in the vicinity thereof between the rotary tool and the material pieces to be welded, thereby to joint the material pieces to be welded to each other.