Offset Centerline Friction Weld Joint for Thermoplastics
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Solution Overview
Problem
Frictional weld joints for thermoplastic materials experience excessive flash generation, leading to waste, reduced strength, and potential failure due to heat losses and loose flash interfering with the joint's integrity, especially in applications like air intake manifolds where flash can mix with engine components.
Innovation Solution
A frictional weld joint design featuring a second bead with an interior and exterior stem, offset centerlines to reduce stress and capture flash within a cavity, enhancing the joint's strength and minimizing flash production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If frictional weld joint uses conventional bead design with aligned centerlines, then manufacturing is simple, but flash generation is excessive and joint strength is reduced
Solution Approach 1:
The patent applies asymmetry by offsetting the centerline of the second bead from the centerline of the first bead. This asymmetric configuration causes the beads to nest more effectively during welding, confining the thermoplastic material and reducing flash generation while simultaneously improving joint strength through better material interlocking.
Solution Approach 2:
The patent segments the second bead into an interior stem and an exterior stem separated by a cavity. This segmentation allows the cavity to capture and contain flash within the bead structure itself, preventing flash from becoming loose while maintaining joint integrity and strength.
2Reliability
If frictional weld joint applies sufficient force for proper nesting, then welding reliability is improved, but heat losses increase due to flash generation
Solution Approach 1:
The patent converts the potentially harmful flash generation into a beneficial feature by designing the second bead with an interior stem and exterior stem that create a cavity. This cavity captures the flash that would otherwise represent energy loss, transforming it into a material that fills the cavity and strengthens the joint from within.
3Manufacturing precision
If flash is generated during welding, then contact surfaces are cleared of contaminants, but loose flash can interfere with joint integrity and become a safety hazard
Solution Approach 1:
The patent extracts the flash from the harmful loose state and confines it within the cavity formed by the interior and exterior stems of the second bead. This extraction removes the hazard of loose flash while preserving the beneficial cleaning effect on contact surfaces during the 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 offset centerline design increases the strength of the frictional weld joint, allowing it to withstand greater pressures without failure, while reducing flash and heat losses, thus improving manufacturing efficiency and joint reliability.
Implementation Method 1
a force is applied to the first body portion to generate friction at the contact surface of the first and second beads. The first and second beads are made from a thermoplastic material and the friction results in an increased temperature of the thermoplastic material.
Implementation Method 2
Subsequently, the force is removed from the first body portion for allowing the thermoplastic material to cool, which results in the first and second beads fusing together.
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A frictional weld joint couples first and second body portions of an article together. The frictional weld joint comprises a first bead extending from the first body portion of the article and a second bead extending from the second body portion of the article. The second bead has an interior stem and an exterior stem space from the interior stem defining a cavity therebetween. The first and second beads are placed in contact with each other with the centerline of the second bead offset from the centerline of the first bead. A force is applied to either the first or second body portions to generate friction between the first and second beads to plastically displace the first and second beads. The force is removed for fusing the first and second beads together to couple together the first and the second body portions of the article.