Friction Stir Welding Mold with Inclined Resistive Wall
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Solution Overview
Problem
The existing methods for joining metal members of different metals, such as in piston shoes, often result in unstable fixation due to the formation of unjoined regions and flash, which reduces joint strength, especially when subjected to impacts.
Innovation Solution
A device and method that involves heating and cooling metal members in contact while rotating, with a mold having an inclined resistive wall to suppress flash growth, ensuring sufficient frictional heat is retained at the joint surface for firm bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the sliding section is fixed to the base section by engagement through deformation, then the production cost is reduced by eliminating machining, but the fixed state becomes unstable when receiving impact
Solution Approach 1:
The invention changes the physical state parameters of the metals by heating them to elevated temperatures during the joining process. This thermal parameter change enables direct joining of different metals (steel base section and copper alloy sliding section) without machining, reducing production cost while creating a stable joint structure that can withstand impact loads.
Solution Approach 2:
The invention creates a composite structure by directly joining dissimilar metals (steel and copper alloy) through controlled heating and cooling. The resulting joint combines the properties of both materials, achieving both cost-effectiveness by eliminating machining and reliability through the stable metallurgical bond formed during the thermal process.
2Temperature
If frictional heat is generated by rotating the first member, then the first and second members are heated for joining, but flash formation drains heat away reducing joint strength
Solution Approach 1:
The invention controls the thermal parameters by regulating the rotation speed, pressure, and heating duration to optimize frictional heat generation. By carefully managing these parameters, sufficient heat is generated at the joint interface for metallurgical bonding while minimizing excessive heat that would cause flash formation and energy loss.
Solution Approach 2:
The invention converts the potentially harmful effect of flash formation into a beneficial process feature. The flash acts as an indicator of adequate heating and material flow, and its controlled formation followed by removal leaves a clean joint surface. The heat that would otherwise be wasted in flash formation is managed through controlled cooling to ensure proper joint strength.
3Strength
If the second member deforms and penetrates into the gap between the first member and sidewall, then flash is formed, but this creates unjoined regions that lower joint strength
Solution Approach 1:
The invention controls the deformation parameters by regulating temperature, pressure, and rotation speed during the joining process. By optimizing these parameters, the second member deforms sufficiently to create metallurgical bonding without excessive deformation that would cause flash and unjoined regions. The controlled parameter changes ensure complete joint surface contact and bonding.
Solution Approach 2:
The invention applies preliminary counter-actions to prevent unjoined region formation. This includes using a mold with specifically designed sidewalls that constrain material flow, applying controlled pressure to maintain contact between the first member and joint surface, and regulating heating to prevent excessive softening that would cause flash formation and bonding defects.
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 effectively restricts the formation of unjoined regions, achieving a strong and stable joint between different metal members by maintaining frictional heat at the interface, enhancing the structural integrity of metal components like piston shoes.
Implementation Method 1
the first and second members are heated with the heat of friction that is generated as the first member slides relative to the second member
Implementation Method 2
The first and second members are then cooled while being maintained in the state in contact with each other, whereby the first and second members are directly joined to each other
Data Source
AI summary
A metal member producing device includes a spindle, a base portion, and a driving portion which drives at least one of the spindle and the base portion in an axial direction of the spindle. Of the spindle and the base portion, one includes a first holding portion for holding a first member. The other has disposed thereon a mold for holding a second member to oppose the first holding portion. The mold includes a bottom wall and a sidewall that extends from the bottom wall in a direction intersecting the bottom wall. The sidewall has a resistive wall formed thereon, the resistive wall being a wall surface inclined with respect to a plane parallel to the axial direction of the spindle so as to face the bottom wall side.