Thermoplastic Blade Sub-assembly Bonding via Induction

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Solution Overview

Problem

The use of thermosetting resins in blade manufacturing is restrictive due to irreversible polymerization and storage expiration issues, and some chemical compounds are toxic or prohibited by legislation, while thermoplastic blades require high-temperature processing that can deform sub-assemblies and lack efficient bonding methods.

Innovation Solution

A method involving the manufacture of sub-assemblies with semi-crystalline and amorphous thermoplastic matrices, where sub-assemblies are bonded using induction heating and amorphous thermoplastic films with ferromagnetic members to promote localized heating and diffusion, allowing for optimized structural integrity and eco-friendly production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thermosetting resins are used in blade manufacturing, then structural integrity is achieved, but irreversible polymerization and storage expiration issues occur

Engineering Contradiction:
Improvestructural integrityVSAvoidstorage stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the material parameter from thermosetting resin to thermoplastic resin, which fundamentally alters the chemical behavior. Thermoplastic resins do not undergo irreversible polymerization and can be stored at room temperature without expiration issues, while still providing adequate structural integrity for blade manufacturing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent utilizes the phase transition properties of thermoplastic resins, which can transition between solid and liquid states through temperature changes. This allows the resin to be processed at elevated temperatures and then cooled to form the final structure, providing both storage stability and structural integrity.

Inventive Principle:
Principle #36Phase transitions

2Reliability

If thermoplastic resins are used to avoid polymerization issues, then storage stability is improved, but high-temperature processing deforms sub-assemblies

Engineering Contradiction:
Improvestorage stabilityVSAvoidassembly deformation
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent divides the blade into separate sub-assemblies that are manufactured independently at room temperature using thermoplastic resins. This segmentation allows each sub-assembly to be produced without high-temperature exposure, preventing deformation, while the final assembly is achieved through bonding techniques that also avoid high temperatures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary manufacturing of sub-assemblies at room temperature before final assembly. By preparing components in advance without high-temperature processing, the sub-assemblies maintain their dimensional stability and can be bonded later using low-temperature thermoplastic bonding techniques.

Inventive Principle:
Principle #10Preliminary action

3Strength

If high-temperature processing is used for thermoplastic blades, then material bonding is achieved, but energy consumption increases

Engineering Contradiction:
Improvematerial bondingVSAvoidprocessing energy
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The patent replaces high-temperature thermal processing with mechanical bonding techniques. Sub-assemblies are bonded together through mechanical interlocking and low-temperature thermoplastic bonding, eliminating the need for high-temperature furnaces and significantly reducing energy consumption while maintaining adequate bonding strength.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Strength

If thermosetting resins are used, then structural strength is achieved, but toxic chemical compounds are required

Engineering Contradiction:
Improvestructural strengthVSAvoidtoxicity
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter from thermosetting resin to thermoplastic resin. Thermoplastic resins are inherently free from toxic chemical compounds and hazardous solvents, providing structural strength through physical rather than chemical bonding mechanisms, thus eliminating toxicity issues.

Inventive Principle:
Principle #35Parameter changes

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 enables the production of thermoplastic blades with improved resistance and bonding, reducing energy consumption and environmental impact, while allowing for storage at room temperature and minimizing manufacturing disparities, and is applicable for both small and large blades.

Implementation Method 1

locally heating each assembly film by induction

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

heating each assembly film by induction according to a judicious heating and pressurizing cycle

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

amorphous thermoplastic films with ferromagnetic members to promote localized heating and diffusion

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3248764B1A method and a thermoplastic blade
Publication Date: 2021.08.11 EUROCOPTER FRANCE SA
  • EP3248764B1 patent drawingFigure 1~7
  • EP3248764B1 patent drawingFigure 8~11
  • EP3248764B1 patent drawingFigure 12~14

AI summary

The present invention relates to a method for manufacturing a blade. The blade comprises subassemblies (10) made of thermoplastic composite materials, each subassembly (10) comprising an internal arrangement (15) and at least one external arrangement (20), each internal arrangement (15) comprising a stack of intermediate layers (16) comprising reinforcing fibers impregnated with a semi-crystalline thermoplastic matrix, each external arrangement (20) comprising at least one surface layer (21) comprising reinforcing fibers impregnated with an alloy of a semi-crystalline thermoplastic polymer and an amorphous thermoplastic polymer. An assembly film comprising an amorphous thermoplastic material and a ferromagnetic element is interposed between two surface layers (21) of two separate subassemblies that are to be joined to each other by a local induction heating process.