Thermoplastic Article Welding for Void-Free Full-Surface Bonding
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Solution Overview
Problem
Existing methods for welding thermoplastic polymer parts, particularly in complex and high-precision applications like RF products, face challenges in achieving whole surface bonds without voids or deformation, and are limited by energy dispersion issues and tooling complexity, especially for multi-layered structures with varying material properties.
Innovation Solution
A method involving assembling non-chemically bonded parts in a tool cavity, sealing it, and melting the assembly to form a chemical bond across the entire interface, using controlled heating and cooling to minimize voids and maintain geometric precision, suitable for thermoplastic polymers with or without fillers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ultrasonic welding or vibrational welding is used to assemble injection moulded parts, then the parts can be chemically bonded through frictional heating, but it is difficult to provide whole surface bonds and the process requires complex energy intensifier features that can lead to voids and un-bonded areas
Solution Approach 1:
The patent removes the energy intensifier features (protrusions, recesses, or irregularities) from the part design that are traditionally required for ultrasonic or vibrational welding. By eliminating these features, the invention avoids the geometric control issues and void formation they cause, while still achieving strong bonds through the alternative heating method.
Solution Approach 2:
The patent replaces the mechanical friction-based heating system (ultrasonic or vibrational welding) with a thermal heating system. Instead of using mechanical energy to melt and bond the parts, the invention uses external heat sources to warm the parts to their melting temperature, allowing for simpler tooling and better geometric control.
2Strength
If energy intensifier features are designed into the initial part moulding to enable ultrasonic or vibrational welding, then chemical bonding can be achieved, but the flow control during welding can lead to voids, un-bonded areas and flash
Solution Approach 1:
The invention extracts and eliminates the energy intensifier features from the part design. By removing these features, the patent prevents the flow control problems that lead to voids and un-bonded areas, while achieving reliable chemical bonds through thermal heating without requiring complex geometric features.
3Ease of manufacture
If conventional welding techniques are used on multi-layer complex shaped geometries, then some parts can be bonded, but the process cannot easily be re-designed to accommodate such assembly processes without affecting the function of the part
Solution Approach 1:
The patent creates a universal heating and bonding process that can accommodate various part geometries and configurations. The thermal heating method combined with vacuum sealing can bond flat, curved, thin, or thick parts regardless of their shape, making the process highly adaptable to different RF product designs without requiring geometry-specific modifications.
Solution Approach 2:
The invention changes the fundamental parameters of the welding process by using thermal heating instead of mechanical vibration or ultrasonic energy. This parameter change allows the process to work with a wide range of part geometries, materials, and thicknesses, providing versatility for complex shaped RF products.
4Strength
If whole surface bonding is achieved through chemical bonding of multiple layers, then mechanical properties and function are improved, but the process complexity increases for multi-layered structures with varying material properties
Solution Approach 1:
The patent merges multiple functions into a single process step: heating, sealing, and bonding are combined in one vacuum heating operation. This eliminates the need for separate heating, clamping, and bonding steps required by conventional methods, reducing process complexity while achieving whole surface bonds across multiple layers with varying materials.
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 achieves high-strength chemical bonds across nearly the entire interface, reducing voids and maintaining geometric precision, suitable for high-throughput manufacturing of complex, multi-layered articles with varying material properties, including RF products.
Implementation Method 1
melting the assembly of at least two parts to chemically bond the at least two parts together
Implementation Method 2
melting the assembly of at least two parts to chemically bond the at least two parts together
Implementation Method 3
sealing the cavity of the tool
Data Source
AI summary
A method of forming shaped articles by welding.