Two-Surface Friction Stir Welding Tool Configuration
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Solution Overview
Problem
Conventional friction stir welding techniques face challenges with economy, tool service life, joint defects, and material rupture due to fixed tool configurations and high energy requirements, especially when welding metals with varying thicknesses and high melting points.
Innovation Solution
A both-side friction stir welding method and apparatus where first and second rotary tools are arranged in opposed relationship, with adjustable protruding and recessed portions, and inclined axes, allowing for independent operation and load control to match metal plate thicknesses, reducing tool wear and improving joint quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional friction stir welding uses fixed tool configurations with probes inserted from one surface, then the welding process is simple to implement, but the tools cannot adapt to metal plates of varying thicknesses and require multiple tool sets
Solution Approach 1:
The welding tool is divided into two separate rotary tools instead of using a single probe inserted from one surface. Each tool has its own drive mechanism, allowing independent adjustment of insertion depths to match varying metal plate thicknesses. This segmentation enables adaptability without requiring multiple complete tool sets.
Solution Approach 2:
The tool configuration allows dynamic adjustment of the insertion depths of the two rotary tools based on the thickness of the metal plates being welded. The tools can be positioned at different depths independently, providing adaptability to varying thicknesses while maintaining a relatively simple overall system structure.
2Strength
If both-side friction stir welding uses two rotary tools arranged in opposed relationship, then the joint strength is improved, but the thermal load on tools increases leading to faster wear and reduced service life
Solution Approach 1:
The two rotary tools are positioned to apply friction stir welding action at different depths and with different pressures. By distributing the welding action partially across two tools rather than concentrating it on one, the thermal load on each individual tool is reduced, extending tool service life while maintaining strong joints.
Solution Approach 2:
The system allows independent control of rotational speeds, insertion depths, and pressing forces for each of the two rotary tools. By optimizing these parameters, the thermal load on each tool can be managed to extend service life while achieving the required joint strength through the combined action of both tools.
3Manufacturing precision
If high pressing force is applied to ensure complete penetration through thick metal plates, then welding quality is improved, but material rupture occurs due to excessive force
Solution Approach 1:
The pressing force required for complete penetration is segmented and applied by two separate rotary tools from opposite surfaces. Each tool applies a portion of the total required force, distributing the mechanical stress to prevent localized material rupture while achieving complete penetration and high welding quality.
Solution Approach 2:
The two rotary tools apply pressing forces from opposite directions that counterbalance each other. This counterweight effect allows high total pressing force to be applied for complete penetration while preventing excessive localized stress that would cause material rupture, as the forces are distributed across the joint.
4Device complexity
If conventional one-side friction stir welding is used, then the equipment setup is simple, but tool wear is high and economy is poor due to frequent tool replacement
Solution Approach 1:
The system uses two rotary tools with independently adjustable insertion depths and rotational speeds. This dynamic configuration allows optimization of the welding process to reduce tool wear, extending tool service life and improving economy while maintaining relatively simple equipment setup and operation.
Solution Approach 2:
By independently controlling the parameters (rotational speed, insertion depth, pressing force) of each rotary tool, the welding process can be optimized to reduce thermal and mechanical loads on the tools. This parameter optimization extends tool service life and improves economic efficiency without requiring complex equipment modifications.
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 approach enhances the economic efficiency of tool usage, improves joint strength, reduces thermal load, and prevents material rupture by allowing for adjustable tool alignment and load distribution, enabling reliable welding of metals with varying thicknesses and high melting points.
Implementation Method 1
the surface of a rotary tool shoulder is brought into contact with surfaces of the materials to be joined while the rotary tool is rotated, and the materials are frictionally stirred by utilizing the frictional heat between the shoulder surface and the materials surfaces
Implementation Method 2
one of the first and second rotary tools includes a tool body having a shoulder portion formed at a tip end portion thereof and at least one protruding portion formed to protrude from the tip end portion of the tool body, the other of the first and second rotary tools includes a tool body having a shoulder portion formed at the tip end portion thereof and at least one recessed portion formed at the tip end portion of the other tool body
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
To perform both-side friction stir welding superior in economy and high in joint strength, first and second rotary tools 3, 4 include tool bodies 3a, 4a having shoulder portions 3c, 4c formed at tip end portions, respectively, the first rotary tool 3 further includes a protruding portion 3d formed to protrude from the tip end portion of the tool body and the second rotary tool 4 further includes a recessed portion 4d formed at the tip end portion thereof for,receiving the tip end of the protruding portion 3d therein when two metal plates 1, 2 are to be welded. The first and second rotary tools are arranged in opposed relationship in the front and back surface sides of a joint portion J of the metal plates, moved to approach to each other to insert the tip end of the protruding portion of the first rotary tool into the recessed portion of the second rotary tool while pressing shoulder surfaces 3b, 4b of the shoulder portions of the first and second rotary tools against the front and back surfaces of the joint portion. In this state, the first and second rotary tools are moved along the joint portion to frictionally stir the entire region in the thickness direction of the joint portion.