Friction Stir Welding Probe Dwelling and Withdrawal
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Solution Overview
Problem
In friction stir welding, a significant issue is the presence of an oxidized film on the boundary face between to-be-jointed members at the probe starting and end points, which affects welding reliability, and the probe withdrawing hole often forms near the joint end point, reducing reliability.
Innovation Solution
The method involves executing dwelling steps at the probe starting and end points to accelerate plastic flow, followed by an end point position avoiding step where the probe is moved away from the end point to withdraw, ensuring the probe withdrawing hole is not near the joint end point, and a withdrawing position dwelling step to smooth the probe withdrawing hole and reduce stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the probe is immediately withdrawn at the probe end point position, then the welding process is efficient and quick, but a probe withdrawing hole is left in the vicinity of the joint end point which reduces welding reliability
Solution Approach 1:
The harmful effect (probe withdrawing hole near joint end point) is eliminated by extracting the probe withdrawal action from the joint end point position and relocating it to a position away from the joint end point, thus removing the source of reliability degradation
Solution Approach 2:
Before withdrawing the probe, the method performs preliminary actions including dwelling at the probe end point position to reduce oxidized film and moving the probe to a position away from the end point, ensuring the withdrawing hole is formed in a safe location that does not compromise joint integrity
2Reliability
If the probe is moved to a position away from the probe end point position before withdrawal, then the probe withdrawing hole is placed away from the joint end point to improve welding reliability, but the welding process time increases
Solution Approach 1:
The probe is moved to a position away from the end point as a preliminary action before withdrawal, ensuring the withdrawing hole is formed in a safe location. This preliminary positioning prevents future reliability issues while adding minimal time to the process
Solution Approach 2:
The method dynamically adjusts the probe position during the welding process, moving from the end point position to a withdrawn position away from the joint, optimizing both reliability and time efficiency through controlled dynamic movement
3Reliability
If a dwelling step is executed at the probe starting and end points, then plastic flow advances and oxidized film is reduced enhancing welding reliability, but the welding process time increases
Solution Approach 1:
The dwelling step applies localized treatment only at critical positions (probe starting and end points) where oxidized film formation is most problematic, rather than throughout the entire welding process. This targeted approach improves reliability at critical locations while minimizing overall process time
Solution Approach 2:
The dwelling step is applied periodically at specific intervals (at the starting and end points) during the welding process, providing necessary plastic flow advancement and oxidized film reduction only when and where needed, balancing reliability improvement with time efficiency
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 significantly reduces the oxidized film at the probe starting and end points, enhancing welding reliability and avoiding the probe withdrawing hole near the joint end point, thereby improving the overall welding process.
Implementation Method 1
plastic flow resulting from frictional heat occurring between the rotating tool and the to-be-jointed members due to movement of the rotating tool
Implementation Method 2
plastic flow advances around the probe starting point position or the probe end point position, thereby accelerating friction stir welding
Data Source
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AI summary
The present invention relates to a technique for producing a jointed member by subjecting two to-be-jointed members which are contacted each other (1 and 2) to friction stir welding. The method for producing a jointed member executes a dwelling step in which a probe (11) is rotated only for a predetermined period at at least one of a probe starting point position (Sp) which is a position of the probe (11) for forming a joint starting point (Sj) in the to-be-jointed member (1) and a probe end point position which is a position of the probe for forming a joint end point in the to-be-jointed member (1).