Friction Stir Welding Pin Structure for Material Waste Deflection
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Solution Overview
Problem
Friction stir welding tools face issues with material waste attaching to the pin holder, leading to deformation and increased maintenance costs due to continuous friction and overheating.
Innovation Solution
The friction stir welding tool design incorporates a ring-shaped receiving surface and adjustable mechanisms to direct material waste away from the pin holder, preventing attachment and facilitating easy replacement of the stir pin, while also including discharge holes to manage material waste effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the stir pin is directly connected to the rotational driving axis, then the structure is simple, but material waste attaches to the pin holder causing deformation and maintenance issues
Solution Approach 1:
The patent introduces a pin holder as an intermediary component between the rotational driving axis and the stir pin. This mediator allows the stir pin to be easily replaceable while the pin holder remains stationary and connected to the driving axis, thus preventing material waste from causing deformation of the driving axis structure while maintaining structural simplicity.
Solution Approach 2:
The patent segments the tool into two separable parts: the stir pin (consumable part that contacts material waste) and the pin holder (reusable part connected to driving axis). This segmentation allows the stir pin to be replaced when worn or contaminated, while the pin holder maintains its structural integrity and connection to the rotational driving axis.
2Reliability
If material waste accumulates on the pin holder, then friction increases causing overheating, but removing material waste requires complex cleaning mechanisms
Solution Approach 1:
The patent enables the stir pin to serve itself by being easily replaceable. When material waste accumulates on the stir pin or pin holder interface, the entire stir pin can be quickly removed and replaced without requiring complex cleaning mechanisms. The stir pin's design allows it to be self-contained and interchangeable, making the system self-maintaining.
Solution Approach 2:
The patent extracts the consumable stir pin as a separate, removable component from the permanent pin holder structure. This extraction allows the stir pin to be removed and discarded when contaminated with material waste, eliminating the need for complex in-situ cleaning mechanisms while maintaining tool reliability.
3Ease of manufacture
If the stir pin structure is simplified for easy replacement, then manufacturing is easier, but material waste management becomes problematic
Solution Approach 1:
The pin holder acts as an intermediary that manages material waste between the simple stir pin and the tool system. The stir pin can be manufactured simply and replaced easily, while the pin holder provides the interface for waste removal and maintains connection to the driving axis, thus resolving the conflict between simplicity and waste management.
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 prevents material waste from attaching to the pin holder, reduces deformation, and extends the lifespan of the tool by managing waste efficiently, resulting in improved joint quality and reduced maintenance costs.
Implementation Method 1
metal workpieces are softened by friction heat generated by the rotation of the tool
Implementation Method 2
a ring-shaped receiving surface and adjustable mechanisms to direct material waste away from the pin holder
Data Source
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AI summary
A stir pin includes: a base end portion holdable by a pin holder; a stirring portion rotatable about a first axis relative to a shoulder member; and an intermediate portion provided between the base end portion and the stirring portion and rotatable about the first axis together with the stirring portion. The intermediate portion includes a first portion and a second portion that is provided further in a first direction than the first portion. The first direction is defined as a direction from the base end portion toward the stirring portion. The first portion includes a protrusion protruding beyond an outer surface of the second portion in a direction away from the first axis. The protrusion has a surface that is pointed in the first direction and defines a ring-shaped receiving surface that receives a material waste generated as a result of a friction stirring.