Friction Stir Welding with Rolling Inner-Corner Support
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Solution Overview
Problem
Friction stir welding apparatuses for forming T-shaped structures face challenges such as complex configurations, increased size, and high costs due to the need for precise control of multiple rotary tools and the occurrence of deformations like galling and burrs at inner corners, especially when using movable pressing members.
Innovation Solution
A friction stir welding apparatus and method that employs a rotary tool and an inner corner presser with a rolling pressing roller to perform friction stir welding on a butted portion, where the presser moves along the butted portion to prevent adhesion and deformations, eliminating the need for multiple rotary tools and reducing apparatus complexity and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a movable pressing member is used to press the inner corner during friction stir welding, then the pressing force can be applied, but deformations such as galling, tears, and burrs occur on the inner corner surface
Solution Approach 1:
The patent replaces the movable pressing member with a stationary pressing member that has a pressing roller. The roller rotates during the friction stir welding process, converting sliding friction into rolling friction. This substitution eliminates the relative movement between the pressing member and workpiece that causes adhesion and deformation, while still maintaining the necessary pressing force to support the workpiece and prevent defects.
Solution Approach 2:
The patent changes the mode of contact from sliding (movable pressing member) to rolling (stationary pressing member with roller). By introducing rotation to the pressing member, the friction characteristics are fundamentally altered, preventing the workpiece material from adhering to the pressing surface while maintaining adequate pressing force throughout the welding process.
2Productivity
If multiple rotary tools are used to perform friction stir welding from both sides of the upright member, then welding can be performed on both inner corners, but the apparatus configuration becomes complex and cost increases
Solution Approach 1:
The patent makes a single rotary tool perform the function of multiple tools by enabling it to approach the butted portion from different directions. The rotary tool is positioned on a movable mechanism that allows it to weld the first inner corner, then be repositioned to weld the second inner corner. This multi-functional approach maintains welding productivity while significantly simplifying the apparatus configuration compared to using two separate rotary tools.
Solution Approach 2:
The patent combines the functions of multiple rotary tools into a single rotary tool by integrating it with a movable positioning mechanism. Instead of having separate tools for each inner corner, one rotary tool is merged with the capability to move and reposition itself, thereby performing welding on both inner corners sequentially. This merging reduces the number of components and simplifies the overall apparatus.
3Manufacturing precision
If a fixed-type pressing member is used to press the entire inner corner, then deformations can be prevented, but the pressing member becomes elongated and heavy, requiring larger fixing means
Solution Approach 1:
The patent segments the pressing function by using a stationary pressing member with a roller that contacts only the specific inner corner region requiring support. Instead of a long elongated member spanning the entire inner corner, the pressing function is localized to the critical area, reducing the size and weight of the pressing member while maintaining effectiveness in preventing deformations.
Solution Approach 2:
The patent replaces a heavy fixed-type pressing member with a stationary pressing member equipped with a roller. The roller mechanism allows the pressing member to be more compact and lighter while still providing adequate pressing force through rotation during the welding process, eliminating the need for large fixing means to support a heavy elongated structure.
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 prevents deformations and reduces the complexity, size, and cost of the apparatus by using a single rotary tool and a rolling pressing roller to press the inner corners, maintaining the shape of the fillet and avoiding issues like galling and burrs.
Implementation Method 1
A rotary tool is plunged into a position at which the workpieces are to be joined together, and frictional heat is generated at the position, which causes a plastic flow of the metal or the like, and thereby these workpieces are joined together.
Implementation Method 2
The inner corner presser includes a pressing roller that presses the other inner corner while rolling in a state where the inner corner presser is being moved by the mover.
Data Source
AI summary
A friction stir welding apparatus (10A) is used at a butted portion (33) where a second workpiece (32) is butted against a first workpiece (31) such that the second workpiece (32) is upright on the first workpiece (31). The friction stir welding apparatus (10A) includes: a rotary tool (11) that is plunged into one inner corner (33a) of a pair of inner corners (33a, 33b) that are positioned, at the butted portion, on both sides of the second workpiece (32), respectively; an inner corner presser (20) that presses the other inner corner (33b) of the pair of inner corners (33a, 33b); and a mover (15) that moves the rotary tool (11) and the inner corner presser (20) along a direction in which the butted portion (33) extends. The inner corner presser (20) includes a pressing roller (21) that presses the other inner corner (33b) while rolling in a state where the inner corner presser (20) is being moved by the mover (15).