Ultrasonic Plastic Rivet Joining Dissimilar Materials
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Solution Overview
Problem
Existing joining processes for dissimilar materials like plastic and metal in vehicle structures often require adhesives or traditional rivets, which may not provide optimal strength or flexibility, especially when considering the compatibility and operational conditions of the components.
Innovation Solution
A method using a one-sided plastic rivet, either button or disc-shaped, that is fused to the components via ultrasonic or friction welding, allowing for secure affixation without adhesives or mechanical deformation, and optionally incorporating spacers for additional stability and spacing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional rivets or adhesives are used to join dissimilar materials (plastic and metal), then the joining process is simple and widely applicable, but the joint strength and structural integrity are insufficient
Solution Approach 1:
The patent replaces traditional mechanical fastening methods (rivets, adhesives) with ultrasonic welding technology. The ultrasonic welding device uses high-frequency vibrations to generate friction heat at the interface between components, melting and fusing the plastic component directly to the metal component, thereby achieving stronger joints without the need for separate fasteners or adhesives.
Solution Approach 2:
The patent changes the physical state of the plastic component during joining by applying ultrasonic energy. The high-frequency vibrations cause localized heating and melting of the plastic material at the joint interface, allowing it to flow and bond with the metal component. After cooling, the plastic solidifies to form a strong permanent joint, effectively changing the material's state from solid to molten and back to solid during the joining process.
2Strength
If welding is used to join dissimilar materials, then strong joints are achieved, but the process becomes more complex and requires specialized equipment
Solution Approach 1:
The patent employs ultrasonic welding technology that uses mechanical vibrations at ultrasonic frequencies (typically 20-40 kHz) to generate heat through friction. This mechanical energy conversion approach eliminates the need for complex thermal welding equipment, arc generation systems, or precision positioning mechanisms required by traditional welding methods, while still achieving strong structural joints.
Solution Approach 2:
The ultrasonic welding process utilizes periodic high-frequency vibrations applied to the joint interface. These rapid oscillations (ultrasonic frequency) create continuous friction heating cycles that melt and fuse the materials. The periodic nature of the vibration allows for controlled heating and cooling cycles, enabling precise control of the welding process with relatively simple equipment compared to continuous thermal or arc welding systems.
3Strength
If mechanical fasteners are used, then the components can be easily assembled and disassembled, but the joint strength and rigidity are compromised
Solution Approach 1:
The patent merges the joining function with the component design itself by creating an integrated joint structure. The plastic component is designed with a geometry that allows direct ultrasonic welding to the metal component, eliminating the need for separate fasteners. The joining process and component formation are combined into a single operation, achieving both strong joints and manufacturing efficiency.
Solution Approach 2:
The plastic component is pre-formed with a specific geometry and surface characteristics that facilitate ultrasonic welding. The component design includes features such as welded surfaces, recesses, or protrusions that optimize the welding interface. This preliminary preparation ensures that when ultrasonic welding is applied, the joint achieves maximum strength without requiring complex assembly procedures or additional fastening elements.
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 effectively joins dissimilar materials like carbon fiber reinforced thermoplastics and steel without adhesives, providing strong and stable interfaces suitable for vehicle structures, enhancing the structural integrity and flexibility of the assembly.
Implementation Method 1
The welding can be ultrasonic welding
Implementation Method 2
The welding can also be friction welding
Data Source
AI summary
A method of joining multiple components is disclosed. The method includes arranging a first component having a first surface, an opposing second surface, and a feature, in contact with a second component having a first surface, an opposing second surface, and defining an aperture. When so arranged, the first surface of the first component is adjacent to the second surface of the second component. The method also includes positioning a fastener on the first surface of the second component and in contact with the feature of the first component, such that at least a portion of the fastener overlaps the aperture on the first surface of the second component. The method additionally includes abutting and fusing the fastener to the feature of the first component to thereby affix the first component to the second component.