Thermoplastic Bonding Into Low-Density Regions for Stable Attachment
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Solution Overview
Problem
Existing methods for bonding objects in automotive and mechanical engineering, such as adhesives and fasteners, face challenges with long-term stability, optical, and acoustic property preservation, particularly when attaching covers with specific physical properties to surfaces like vehicles and machines.
Innovation Solution
A method involving a first object with thermoplastic material that penetrates into a second object's region of low density under mechanical pressing force and excitation, forming a positive-fit connection by liquefying and resolidifying, which allows for deep anchoring without compromising optical or acoustic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesives are used to attach the cover to the surface, then the bonding can be achieved, but the long term stability is poor and the process is time consuming
Solution Approach 1:
The patent utilizes the phase transition of thermoplastic material from solid to molten state through friction heating during ultrasonic vibration, and then back to solid state for resolidification. This phase transition enables rapid bonding without lengthy hardening processes required by adhesives, while creating a mechanically interlocked structure that ensures long-term stability.
Solution Approach 2:
The invention employs ultrasonic vibration to generate friction heat that melts the thermoplastic material, enabling rapid bonding. The mechanical vibration also creates dynamic mixing and penetration of molten material into the porous structure, forming a strong mechanical interlock that provides both speed and long-term reliability.
2Strength
If fasteners that penetrate the cover are used, then the attachment can be achieved, but the optical and acoustic properties are compromised
Solution Approach 1:
The patent applies bonding locally at the interface between the cover and surface through ultrasonic vibration, rather than using through-going holes. The thermoplastic material is melted and penetrated only into the porous structure of the surface, creating a localized mechanical interlock that maintains the integrity and appearance of the cover while providing strong attachment.
3Reliability
If adhesives are used for bonding, then the attachment can be achieved, but the treatment of extensive area is needed and it is limited to certain body geometries
Solution Approach 1:
The bonding process is segmented into localized bonding points or lines where ultrasonic vibration is applied, rather than treating the entire surface area with adhesive. This segmentation allows the process to handle complex geometries and three-dimensional surfaces efficiently, reducing process complexity while maintaining bonding reliability.
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 provides a stable and effective bonding solution that maintains the desired physical properties of the objects, including acoustic damping and mechanical resistance, while avoiding the limitations of traditional adhesives and fasteners.
Implementation Method 1
Applying a mechanical pressing force and a mechanical excitation capable to liquefy the thermoplastic material
Implementation Method 2
Applying a mechanical pressing force and a mechanical excitation capable to liquefy the thermoplastic material
Data Source
AI summary
A method of bonding a first object to a second object includes the steps of: providing the first object including thermoplastic material in a solid state, providing the second object including a proximal surface, applying a mechanical pressing force and a mechanical excitation capable to liquefy the thermoplastic material until a flow portion of the thermoplastic material is flowable and penetrates into structures of the second object, and stopping the mechanical excitation and letting the thermoplastic material resolidify to yield a positive-fit connection between the first and the second object. The second object has a region of low density, wherein the protrusion penetrates the region of low density at least partly before the thermoplastic material is made flowable, and wherein the first object includes a protruding portion after the step of letting the thermoplastic material resolidify, the protruding portion at least partly penetrates the region of low density.