Double-Sided Refill Friction Stir Spot Welding for Thick Joints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional refill friction stir spot welding techniques face limitations such as constrained welding depth, inability to weld thicker joints, and challenges with multi-stack joints due to high melting temperatures of intermediate materials.
Innovation Solution
A method involving two welding heads with probe members and tubular shoulders, where both heads are simultaneously rotated and advanced into the weld object from opposing surfaces, allowing for deeper penetration and increased heat distribution, thereby overcoming the limitations of conventional techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional refill FSSW is used to avoid consumable material and exit holes, then welding cleanliness is improved, but welding depth is constrained by machine plunge depth
Solution Approach 1:
The welding system is segmented into two independent welding heads operating from opposite sides of the workpiece. Each head can independently control probe and shoulder movement, allowing the first head to weld through the first component while the second head welds through the second component, thereby achieving greater total welding depth than a single head could reach.
Solution Approach 2:
The solution transitions from single-sided welding to dual-sided welding, adding a spatial dimension to the welding process. By positioning welding heads on both sides of the workpiece and coordinating their movements, the system achieves penetration through the entire thickness of multi-stack joints that would be impossible from a single side.
2Manufacturing precision
If conventional refill FSSW is used, then exit holes are avoided, but thicker joints cannot be welded
Solution Approach 1:
The welding system is segmented into two independent welding heads operating from opposite sides of the workpiece. Each head can independently control probe and shoulder movement, allowing the first head to weld through the first component while the second head welds through the second component, thereby achieving greater total welding depth than a single head could reach.
Solution Approach 2:
The patent merges two welding operations into a coordinated simultaneous process. The first and second welding heads work together on multi-stack joints, with their probe and shoulder movements synchronized to achieve penetration through the entire thickness of the joint assembly, effectively combining their capabilities to overcome individual depth limitations.
3Productivity
If conventional refill FSSW is used, then single-sided welding is performed, but heat losses occur and welding efficiency is reduced
Solution Approach 1:
The patent merges two welding operations into a coordinated simultaneous process. The first and second welding heads work together on multi-stack joints, with their probe and shoulder movements synchronized to achieve penetration through the entire thickness of the joint assembly, effectively combining their capabilities to overcome individual depth limitations.
Solution Approach 2:
By performing welding from both sides simultaneously, the process eliminates idle time and continuous heat generation is maintained throughout the workpiece thickness. The coordinated movement of both welding heads ensures continuous plasticization and welding action without the interruptions that would occur in sequential single-sided welding.
4Productivity
If conventional refill FSSW is used, then single probe-shoulder coordination is employed, but welding time increases and previous welds may be degraded
Solution Approach 1:
The patent merges two welding operations into a coordinated simultaneous process. The first and second welding heads work together on multi-stack joints, with their probe and shoulder movements synchronized to achieve penetration through the entire thickness of the joint assembly, effectively combining their capabilities to overcome individual depth limitations.
Solution Approach 2:
The system employs dynamic coordination between two welding heads, where probe and shoulder movements are continuously adjusted in real-time based on material response. This dynamic control allows optimization of welding parameters during the process, achieving both speed and quality that static single-head systems cannot match.
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 method enables the creation of stronger, deeper welds with increased efficiency, allowing for the welding of thicker joints and multi-stack joints that were previously impractical, while avoiding heat losses and improving material intermixing.
Implementation Method 1
Friction stir welding is a solid state joining process that uses frictional heat generated by a rotating tool to join materials
Implementation Method 2
utilizes a redesigned tool to achieve spot welding without exit-hole by advancing a probe into the object to be welded while simultaneously retracting a tubular shoulder surrounding the probe, with both the probe and the shoulder being rotated. During this movement, material plasticised by friction between the probe and the object to be welded
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a method for performing simultaneous double refill friction stir spot welding, comprising: providing a first welding head (110) comprising a first probe member (102) and a first tubular shoulder (104); providing a second welding head (210) comprising a second probe member (202) and a second tubular shoulder (204); locating the first welding head (110) on a first surface of a weld object to be welded such that the first probe member (102) and the first tubular shoulder (104) are in contact with the first surface; locating the second welding head (210) on a second surface of the weld object (112), opposing the first surface; simultaneously rotating the first welding head and the second welding head so as to form a volume of materials of increased plasticity in the weld object proximate the first and second welding heads; simultaneously advancing one of the first probe member (102) and the first tubular shoulder (104), and one of the second probe member (202) and the second tubular shoulder (204), from an initial position and into the respective first and second surface of the weld object (112) along the respective first and second head axis (108, 208), while retracting the other of the first probe member (102) and the first tubular shoulder (104) and the second probe member (202) and the second tubular shoulder (204) from an initial position and along the respective first and second head axis (108, 208); returning each of the first and second probe member (102, 202) and first and second tubular shoulder (104, 204) towards the initial position; removing the first and second welding head (110, 210) from the respective first and second surface of the weld object (112).