Retractable Friction Stir Welding Head for Hole-Free Weld Exit
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Solution Overview
Problem
Conventional friction stir welding heads mounted on numerically controlled machine tools lack a retractable pin feature, which is necessary to fill the hole left at the weld exit, posing challenges in applications like aeronautics and space where a smooth weld surface is critical.
Innovation Solution
A compact and universal friction stir welding head with a retractable pin mechanism, integrated into a machine tool with a rotating spindle, allowing the central pin to adjust its position relative to the peripheral shoulder, enabling it to project and retract seamlessly during the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional friction stir welding head is used, then the welding process is simple and the device is compact, but a hole is left at the weld exit which is problematic for certain applications
Solution Approach 1:
The central pin is made retractable relative to the peripheral shoulder, allowing it to dynamically adjust its position. During welding, the pin protrudes to perform the welding operation, and after welding, the pin retracts to plug the hole at the weld exit. This dynamic adjustment enables the same welding head to achieve both welding functionality and hole plugging, improving weld surface quality without requiring a completely separate device.
Solution Approach 2:
The welding head is designed to perform multiple functions: the central pin serves both as the welding tool during the welding process and as a plug for the weld exit hole afterward. This multi-functionality allows a single device to address both the welding operation and the surface quality requirement, eliminating the need for additional specialized equipment while maintaining compactness.
2Manufacturing precision
If a retractable pin is added to plug the hole at weld exit, then the weld surface quality improves, but the device complexity increases and adaptability to universal machine tools decreases
Solution Approach 1:
The welding head is divided into separable components: the central pin assembly with retractable mechanism, the peripheral shoulder, and the drive interface. This segmentation allows the core welding function to be maintained while adding the retractable pin capability, and enables the head to be adapted to different machine tool spindles without redesigning the entire system.
Solution Approach 2:
The welding head incorporates a standardized external interface that can be mounted on various machine tool spindles, making it universally adaptable. The retractable pin mechanism is integrated into this universal design, allowing the same head to perform both welding and hole plugging functions across different machine tools without sacrificing compatibility.
3Manufacturing precision
If the central pin is made retractable, then the hole at weld exit is plugged, but the device complexity and mechanical structure become more complex
Solution Approach 1:
The central pin is nested within the peripheral shoulder assembly, with the pin capable of moving axially relative to the shoulder. The retraction mechanism is integrated within the existing head structure, utilizing the space already available in the nested configuration. This approach adds the hole plugging function while minimizing the increase in overall device complexity by utilizing the existing nested architecture.
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
The solution allows for a seamless weld surface without leaving a hole at the weld exit, accommodating various thicknesses and ensuring a high-quality weld, making it suitable for applications requiring precision like aeronautics and space industries.
Implementation Method 1
a first device for transmitting rotation from the external interface piece to the primary rotating shaft around the first axis of rotation
Implementation Method 2
a second device for translating the central rotating shaft along the first axis of rotation from the motor during the rotation of the central rotating shaft and the shoulder fixing piece around the first axis of rotation
Implementation Method 3
Friction stir welding uses a specific welding tool with a central pin that protrudes from a peripheral shoulder. This welding tool is rotated to penetrate the two mechanical parts to be welded
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention relates to a friction stir welding head (1), comprising a central pin shaft (201), a peripheral shoulder piece (301) (100), a shaft (302) for rotating the piece (301) and the shaft (201) about the axis (AX1), the shaft (201) being rotationally fixed to the piece (301) and free to translate relative to the piece (301) along the axis (AX1), the head (1) comprising an external interface piece (350) for being fixed to a rotating spindle (B) of the machine (M), a device (310) for transmitting rotation of the shaft (302) about the axis (AX1) from the piece (350), and a device (210) for translating the shaft (201) along the axis (AX1) from the motor (250) during the rotation of the shaft (201) and the part (301).