Friction Stir Welding Bobbin Tool with Adjustable Rotating Bodies
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Solution Overview
Problem
Conventional friction stir welding apparatuses face issues with excess heating leading to coarse joining quality due to the fixed-pin configuration and separate non-rotating slide parts, which require moving the entire housing for position adjustments and result in incomplete filling of gaps, potentially causing joining failures.
Innovation Solution
A friction stir welding apparatus with a bobbin-type rotating tool featuring adjustable upper and lower rotating bodies, equipped with slide plates and sensors for precise load and position control, allowing the tool to clamp and stir joints without rotating the slide plates, thereby preventing excess heating and ensuring complete filling of gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed-pin configuration with a separate non-rotating slide part is used, then the apparatus structure is simplified, but the finished surface quality deteriorates due to excess heating and the inability to adjust position independently
Solution Approach 1:
The rotating tool is segmented into multiple independent components: an upper rotating body with a slide plate, a lower rotating body, and a stirring part. Each component can be adjusted independently in the axial direction through actuators, allowing the slide plate to contact and slide on the joint surface without rotating while the stirring part performs friction stir welding. This segmentation resolves the contradiction by enabling both structural simplicity and high surface quality through independent position adjustment.
2Ease of operation
If the whole housing is moved for position adjustment of the slide part, then the slide part position can be adjusted, but the device complexity and operation difficulty increase
Solution Approach 1:
The slide plate is made dynamically adjustable through an actuator that enables independent axial movement relative to the housing. This dynamic adjustment mechanism allows the slide plate position to be changed without moving the entire housing, simplifying the overall device structure while maintaining ease of operation for position adjustment.
3Ease of manufacture
If the shoulder surface of the probe does not plunge into the members to be joined, then the slide part can slide on the joint surface, but gaps in the joint cannot be filled resulting in joining failure
Solution Approach 1:
The tool is segmented into a slide plate for surface contact and a stirring part for material processing. The stirring part can plunge into the joint and fill gaps while the slide plate maintains surface contact, resolving the contradiction between ease of manufacture and joining reliability through functional segmentation.
Solution Approach 2:
The stirring part acts as an intermediary between the slide plate and the joint material. While the slide plate slides on the joint surface, the stirring part penetrates the joint to fill gaps and ensure proper material flow, mediating between the non-invasive sliding action and the invasive gap-filling requirement.
4Manufacturing precision
If the rotating bodies are made adjustable in axial direction, then the finished surface quality improves, but the device complexity increases due to additional actuators
Solution Approach 1:
The upper and lower rotating bodies are made dynamically adjustable through actuators that enable independent axial movement. This dynamic capability allows precise control of the slide plate and stirring part positions to achieve high finished surface quality, justifying the increased device complexity through improved manufacturing precision.
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 solution enables a smooth, gap-free joint surface without the need for post-weld grinding, reducing machining costs and resulting in a higher quality finish with reduced product costs.
Implementation Method 1
a slide plate (5) attached, through a thrust bearing (41), to the lower end of the upper rotating body (2)
Implementation Method 2
the stirring part (4) is rotated to stir the joint by frictional heat to join the members
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A friction stir welding apparatus (10) includes a rotating tool (1) provided with an upper rotating body (2) arranged to be axially adjustable in position by an upper actuator (20A), a lower rotating body (3) integral with a rotating main rod (16) extending through the upper rotating body and arranged to be axially adjustable in position by a lower actuator (20B), and a stirring part (4) formed in the rod (16). The upper rotating body (2) and the lower rotating body (3) clamp therebetween a joint (310) of members to be joined (300) placed with their end faces butting each other. The stirring part is rotated to stir the joint by frictional heat to join them. The rotating tool (1) includes a slide plate (5, 6) attached, through a thrust bearing (41, 42), to one or both of end portions of the upper rotating body (2) and the lower rotating body (3) facing each other to provide good finished surfaces of the joint.