Friction Stir Spot Welding Clamp for Higher Joint Fatigue Strength
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Solution Overview
Problem
Friction stir spot welding techniques face challenges in improving the fatigue strength of joint portions without compromising manufacturing efficiency.
Innovation Solution
A clamp member with a protruding portion that extends around the axis to press the workpiece, applying compressive plastic strain and residual stress during and after welding, allowing for efficient improvement of fatigue strength without the need for additional pressing devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a process for improving fatigue strength is added to friction stir spot welding, then the fatigue strength of joint portion is improved, but the manufacturing efficiency is reduced
Solution Approach 1:
The invention combines the pressing function with the clamp member that is already part of the friction stir spot welding device. The clamp member is modified to include a pressing portion that can apply compressive force to the workpiece during or after welding, thereby integrating the fatigue strength improvement process into the existing welding operation without requiring a separate pressing device or additional process steps.
Solution Approach 2:
The clamp member is designed to perform multiple functions: it clamps the workpiece during welding and simultaneously presses the workpiece to apply compressive stress for improving fatigue strength. This multi-functional design eliminates the need for dedicated pressing equipment and maintains manufacturing efficiency while achieving the desired fatigue strength improvement.
2Strength
If a dedicated pressing device is prepared to compress the workpiece, then the fatigue strength can be improved, but the cost and work load increase
Solution Approach 1:
The clamp member is designed to perform multiple functions: it clamps the workpiece during welding and simultaneously presses the workpiece to apply compressive stress for improving fatigue strength. This multi-functional design eliminates the need for dedicated pressing equipment and maintains manufacturing efficiency while achieving the desired fatigue strength improvement.
Solution Approach 2:
The clamp member, which is already an essential component of the welding device, is modified to include pressing capability. This allows the existing device to serve itself by performing both welding and fatigue strength improvement functions, eliminating the need for external dedicated pressing equipment and reducing overall system complexity and cost.
3Force
If the pressing area is increased to properly compress the workpiece, then sufficient compressive force is applied, but a dedicated pressing device is required
Solution Approach 1:
The pressing portion is designed with a specific local geometry that concentrates the compressive force at the critical friction stir region of the workpiece. By optimizing the shape and position of the pressing portion, sufficient compressive stress is applied to the joint area without requiring a large pressing area or dedicated pressing equipment, thereby maintaining force effectiveness while avoiding increased device complexity.
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 effectively enhances the fatigue strength of joint portions while maintaining manufacturing efficiency and reducing costs and workload, enabling efficient multiple welding operations with reduced productivity loss.
Implementation Method 1
the surface of at least one of the friction stir region of the workpiece and the adjacent region adjacent to the friction stir region can be pressed with the protruding portion of the clamp member. With this operation, the workpiece can be compressed, and residual stress can be applied to the joint portion of the workpiece.
Implementation Method 2
a pin member and a shoulder member that can rotate around a predetermined axis independently of each other
Implementation Method 3
double-acting friction stir spot welding device provided with a pin member and a shoulder member that can rotate around a predetermined axis independently of each other
Data Source
Figure 1
Figure 2~3
Figure 4(a)~4(f)
AI summary
A clamp member for a double-acting friction stir spot welding device is a clamp member that is provided for a double-acting friction stir spot welding device for performing friction stir spot welding of a workpiece by using a rotary tool, and presses a surface of the workpiece while the workpiece is supported. The rotary tool has a pin member and a shoulder member. The clamp member includes an end face that comes into surface contact with the surface of the workpiece to press the surface and a protruding portion protruding from the end face in an axial direction and extending around an axis, the protruding portion being configured to press the workpiece, the clamp member surrounding an outer periphery of the shoulder member.