Friction Stir Welding Pin with Soft Nitrided Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing friction stir welding apparatuses face issues with tool longevity due to adhesion of intermetallic compounds and are often bulky and heavy, requiring frequent tool replacements and complicating integration with robots.
Innovation Solution
A compact and lightweight friction stir welding apparatus design featuring an upper-side and lower-side rotation shoulder with a single load actuator, a position sensor, and a controller, supported by a robot, which reduces the size and weight while extending tool life through a soft nitrided layer on the pin to prevent adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If diamond-like carbon coating is applied on the pin and shoulder to prevent adhesion, then adhesion prevention is improved, but tool lifetime is reduced due to exfoliation under high temperature and pressure
Solution Approach 1:
The patent changes the material parameter of the coating from diamond-like carbon to soft nitrided layer, which maintains adhesion prevention capability while exhibiting superior resistance to exfoliation under high temperature and pressure conditions, thereby extending tool lifetime
Solution Approach 2:
The patent uses a composite structure combining a steel base material with a soft nitrided layer coating, creating a material system that leverages both the strength of steel and the adhesion-resistant properties of the nitrided layer, achieving balanced performance in terms of adhesion prevention and durability
2Ease of operation
If a process head is provided movably on a gate-shaped column to accommodate rotation tool, then welding function is achieved, but apparatus size is increased
Solution Approach 1:
The patent extracts and eliminates the complex gate-shaped column and movable process head structure, retaining only the essential welding components (pin, shoulder, actuators) mounted directly on the robot, thereby dramatically reducing apparatus size while preserving welding functionality
Solution Approach 2:
The patent makes the robot serve multiple functions: it provides positioning, movement, and support for the welding apparatus, replacing the need for dedicated complex mechanical structures, thus reducing overall system size and complexity
3Extent of automation
If actuators are mounted on the process head for rotation and axial movement, then welding control is achieved, but apparatus weight is increased
Solution Approach 1:
The patent merges the welding apparatus components with the robot system, mounting the pin, shoulder, and actuators on the robot's end effector rather than using a separate heavy process head, thereby achieving welding control while minimizing apparatus weight
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 apparatus achieves a stable and efficient welding process with reduced tool replacement frequency and enhanced mobility, allowing for easier robot integration and improved position control, maintaining a stable joint despite workpiece softening or expansion.
Implementation Method 1
a soft nitrided layer on the pin to prevent adhesion
Implementation Method 2
Based on generated friction heat and stirring according to rotation, friction stir welding is performed
Implementation Method 3
a load control unit that controls a load applied on a work by the upper-side rotation shoulder
Implementation Method 4
the base plate is moved upward and downward by a robot that is controlled by the controller
Data Source
AI summary
The friction stir welding apparatus includes a pin (20) on which a soft nitrided layer (50) is formed. The soft nitrided layer (50) is formed of an iron lithium oxide layer (51) and a nitrided diffusion layer (52). The atom of the iron lithium oxide layer (51) penetrates into a space between atoms at the surface of the pin (20) to form the nitrided diffusion layer (52).