Double-Acting Friction Stir Spot Welding Clamp for Thick Welds
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Solution Overview
Problem
Conventional double-acting friction stir spot welding methods struggle to create thick, strong welds with a clear boundary between stirred and non-stirred material, leading to potential weaknesses in the welded joint.
Innovation Solution
A holding jig with a cylindrical clamp member featuring an inclined surface that forms a concave region, combined with a backing member having a circular concave portion, allows for the filling of material into these regions during the welding process, creating thickened welds with the stirred portion boundary located at the thick region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional double-acting friction stir spot welding is used, then the welding process is simple, but the weld strength and rigidity are insufficient
Solution Approach 1:
The holding jig is configured in advance with inclined surfaces that form concave regions, and the backing member has pre-formed circular concave portions. These preliminary geometric configurations enable material accumulation during the welding process, creating thickened weld regions that enhance strength without requiring complex post-processing or additional welding steps.
2Strength
If material is accumulated to form thick welds, then weld strength increases, but the manufacturing process becomes more complex
Solution Approach 1:
The inclined surfaces on the holding jig and the circular concave portions on the backing member create localized regions where material accumulates during welding. This local quality change forms thickened weld regions specifically at the concave areas, enhancing joint strength where needed while maintaining simplicity in the overall manufacturing process.
3Shape
If a clear boundary is formed between stirred and non-stirred material, then material structure is defined, but weld homogeneity decreases
Solution Approach 1:
The inclined surfaces and circular concave portions introduce a geometric dimension to the welding process, creating three-dimensional material distribution patterns. Material accumulates in the concave regions forming thickened welds with defined boundaries, achieving both structural definition and enhanced homogeneity through spatial configuration rather than material composition changes.
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 configuration enhances the strength and rigidity of the weld by forming thick regions on both surfaces of the workpiece, reducing the likelihood of breakage and improving the joint's resistance to tensile loads.
Implementation Method 1
The pin member and the shoulder member can rotate and advance/retract independently. These rotary tools are pressed (press-fitted) into workpieces such as a metal material. The workpieces are softened and stirred by using frictional heat with the workpieces, thereby welding the workpieces to each other.
Implementation Method 2
a clamp member that presses and supports a workpiece is often used. Because the clamp member can stably support a workpiece by pressing the workpiece, the pin member or shoulder member that rotates at high speed can be properly pressed into the workpiece.
Data Source
AI summary
In a double-acting friction stir spot welding device or a double-acting friction stir spot welding method, a pin member and a cylindrical shoulder member that rotates around the axis of the pin member are used as rotary tools, and a clamp member that has a cylindrical shape positioned so as to surround the outside of the shoulder member and is configured to press a workpiece from an obverse surface with an annular pressing surface of the distal end is used as a holding jig. The clamp member has an inclined surface that is adjacent to the inner edge portion of the pressing surface and inclined so as to reduce the inner diameter of the clamp member toward the back side as viewed from the pressing surface.