Multi-Material Three-Member Joining Using Spot and Friction Stir Welding
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Solution Overview
Problem
Existing vehicle body manufacturing methods are limited in joining three members of different materials effectively, particularly in achieving strong and durable connections.
Innovation Solution
A joining system and method utilizing a friction stir welding machine with a rotatable and movable tool, a welder for electric resistance spot welding, and a controller to soften and intermingle materials, allowing for the joining of three members with different material compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional welding methods (electric resistance spot welding) are used to join three members of different materials, then the joining process is simple, but the joining strength and reliability are insufficient
Solution Approach 1:
The joining process is divided into two distinct stages: first, electric resistance spot welding joins the second and third members; second, friction stir welding joins the first member to the welded pair. This segmentation allows each welding method to be optimized for its specific function, achieving strong multi-material joints while maintaining process clarity
Solution Approach 2:
The second and third members are pre-welded together using electric resistance spot welding before the friction stir welding process begins. This preliminary action creates a stable base structure that enables the subsequent friction stir welding to effectively join all three members with enhanced strength
2Reliability
If friction stir welding is used to join three members of different materials, then the joining strength is improved, but the process complexity increases
Solution Approach 1:
The friction stir welding tool is designed with universal applicability to handle multiple material types (aluminum, magnesium, steel) in a single joining operation. The tool's rotational and linear motion capabilities enable it to effectively join dissimilar materials, enhancing reliability across different material combinations
Solution Approach 2:
The system merges two welding technologies (electric resistance spot welding and friction stir welding) into a coordinated multi-stage process. The controller integrates both welding operations, combining their advantages to achieve high-reliability joints among three different materials while managing system complexity through unified control
3Ease of manufacture
If a single welding method is used to join three members, then the device complexity is reduced, but the joining effectiveness for multi-material connections is insufficient
Solution Approach 1:
The manufacturing process is segmented into two sequential steps: first, spot welding the second and third members; second, friction stir welding the first member to the welded pair. This segmentation enables each method to be used where it is most effective, achieving strong multi-material joints without requiring complete process redesign
Solution Approach 2:
The second and third members are pre-welded using simple electric resistance spot welding before the friction stir welding operation. This preliminary action maintains manufacturing simplicity for the initial joining while setting up the structure for the subsequent strength-enhancing friction stir welding process
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 system achieves strong and reliable connections among three members, enhancing the tensile strength and durability of the joined target, surpassing the limitations of conventional methods.
Implementation Method 1
causing the second member and the third member that are softened to intrude into the first member that is softened, thus joining the joining target
Implementation Method 2
causing the welder to weld the second member and the third member to each other
Data Source
AI summary
A joining system (100) of the present invention is for joining a joining target (W) including first, second, and third members (W1), (W2), (W3), and includes a welder (101), a friction stir welding machine (102), and a controller (110) that: (A) causes the welder (101) to weld the second and third members (W2), (W3); (B), after (A), causes the joining target (W) to be placed at the friction stir welding machine (102) so that the first member (W1) is opposed to a distal end of a tool (10); and (C), after (B), controls a linear motion driver (7) and a rotation driver (8) so as to, while pressing the distal end of the tool (10) to the joining target (W), rotate the tool (10) around an axis, so that the softened second and third members (W2), (W3) intrude into the softened first member (W1), thus joining the joining target (W).