Friction Stir Weld Exit Control for High-Hardness Joined Bodies
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Solution Overview
Problem
Existing methods for friction stir welding, such as those described in Patent Literatures 1-3, face challenges in achieving a good surface finish and preventing damage to the rotary tool, especially when removing the tool from a jacket body with higher hardness.
Innovation Solution
A method for manufacturing a joined body involves friction stir welding between a first metal member (jacket body) with higher hardness and a second metal member (sealing body) with lower hardness, where the rotary tool is removed while gradually decreasing its rotational speed from the predetermined speed used during welding, ensuring the tool is extracted from the jacket body without causing excessive frictional heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the rotary tool is made to leave the jacket body while increasing the rotational speed, then the rotary tool can be removed from the jacket body, but excessive frictional heat is input to the jacket body causing cracks, burrs, wall thinning, and surface finish deterioration
Solution Approach 1:
The patent applies parameter changes by controlling the rotational speed of the stirring pin during the leaving process. Specifically, the rotational speed is maintained at a predetermined speed that prevents excessive frictional heat generation, thereby avoiding surface finish deterioration, cracks, and other defects while still enabling successful tool removal from the high-hardness jacket body.
2Ease of operation
If the rotary tool is made to leave the jacket body with higher hardness, then the tool can be removed, but increased wear occurs on the rotary tool leading to damage
Solution Approach 1:
The patent resolves this contradiction by maintaining the rotational speed at a predetermined level during the leaving process. This controlled speed parameter reduces frictional heat and wear on the rotary tool, preventing damage and extending tool life while still achieving successful removal from the high-hardness jacket body.
3Strength
If friction stir welding is performed on the butted portion, then the jacket body and sealing body are joined together, but a removal hole is left after removing the rotary tool requiring pre-processing repair
Solution Approach 1:
The patent applies the extraction principle by removing the stirring pin through the sealing body rather than the jacket body. Since the sealing body is softer and more ductile, it can accommodate the removal hole without requiring repair. This extracts the problematic removal hole from the jacket body (where it would interfere with electronic component installation) and places it in the sealing body where it is acceptable.
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 achieves a good surface finish for the joined body and prevents damage to the rotary tool, allowing for the installation of electronic components without pre-processing and enhancing design flexibility and productivity.
Implementation Method 1
friction stir welding is performed to the butted portion by moving the stirring pin of the rotary tool at a predetermined depth along a set moving track
Data Source
AI summary
A method for manufacturing a joined body by friction stirring a first metal member and a second metal member, includes a butting process and a primary joining process. In the primary joining process, an ending position is set on the first metal member at an outer side relative to a set moving track, and a leaving section is provided, in which after friction stir welding to the butted portion, the rotary tool is moved toward the ending position and is made to leave the first metal member at the ending position. The friction stirring is performed to the butted portion while rotating the stirring pin at a predetermined rotational speed. The rotary tool is made to leave the first metal member in the leaving section when the rotary tool is moved to the ending position while gradually decreasing a rotational speed of the stirring pin from the predetermined rotational speed.