Shoulderless Friction Stir Welding Probe for Burr Suppression
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Solution Overview
Problem
In friction stir welding, existing rotating tools face challenges in maintaining a narrow joint width and suppressing burr formation, especially when the stirring region is deep, leading to increased load on the welding device and potential damage to the stir probe.
Innovation Solution
A rotating tool with a stir probe featuring a pressure receiving surface inclined to the rotation axis, where the pressure receiving region is perpendicular to the rotation tangential direction, is used to generate plastic flow in the rotation direction, reducing the proportion of plastic flow in the axis direction and suppressing burr formation without a shoulder, thus maintaining a narrow joint width even at deep stirring regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the outer diameter of the stir probe is increased to handle deep stirring regions, then the torque and resistance increase, but the joint width increases and the load on the welding device increases
Solution Approach 1:
The pressure receiving surface is provided only on a specific region of the side surface of the stir probe, not the entire surface. This localized feature creates plastic flow in the rotation direction at the critical area where burr formation occurs, while maintaining a narrow overall probe diameter for deep stirring applications.
2Area of stationary object
If the outer diameter of the shoulder is reduced or the shoulder is eliminated to reduce joint width, then the joint width decreases, but plastic flow cannot be restrained from flowing as burr and the load on the stir probe increases
Solution Approach 1:
The invention extracts the burr suppression function from the shoulder component and integrates it directly into the stir probe through the pressure receiving surface. This eliminates the need for a separate shoulder while maintaining the ability to control plastic flow and prevent burr formation.
Solution Approach 2:
The pressure receiving surface changes the direction of plastic flow from the rotation axis direction to the rotation direction. By altering the flow parameters through the inclined surface geometry, the system achieves burr suppression without requiring a shoulder to mechanically restrain the material.
3Object-generated harmful factors
If the area difference between anti-insertion side inclined surface and insertion side inclined surface is increased to suppress burr, then burr suppression improves, but the outer diameter of the stir probe cannot be reduced
Solution Approach 1:
The pressure receiving surface is provided asymmetrically on the side surface of the stir probe, specifically on the region corresponding to the anti-insertion side. This asymmetric configuration generates plastic flow that suppresses burr formation while maintaining a compact, reduced outer diameter throughout the stir probe.
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 design effectively reduces burr occurrence and joint width, enhances joining strength, and improves the durability of the stir probe by directing plastic flow efficiently, while maintaining high-speed joining capabilities without increasing the load on the welding device.
Implementation Method 1
the rotating tool which rotates at high speed is abutted and pressed against the surface of to-be-joined members, and thereby metal in the vicinity of a joint portion is softened by the heat of friction and the action of stirring, generating a plastic flow
Implementation Method 2
metal in the vicinity of a joint portion is softened by the heat of friction and the action of stirring, generating a plastic flow
Implementation Method 3
metal in the vicinity of a joint portion is softened by the heat of friction and the action of stirring
Data Source
AI summary
A pressure receiving surface inclined to a rotation axis is provided on the side surface of a stir probe of a rotating tool. The pressure receiving surface includes a pressure receiving region which is always perpendicular to a rotation tangential direction in a cross section perpendicular to the rotation axis. In friction stir processing, the stir probe is caused to rotate in a rotation direction B in which the normal direction of the pressure receiving surface is positive. According to this kind of rotating tool, as it has no shoulder, a joint width does not increase even when a stirring region is deep, and also, a plastic flow in a rotation direction is generated by a pressure receiving surface, so that it is possible to reduce the proportion of the plastic flow in the rotation axis direction, and thus possible to suppress an occurrence of burr.