Thermoplastic Insert Welding for Rotor Blade Tolerance Gaps

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Solution Overview

Problem

Current thermoplastic welding techniques for wind turbine rotor blade components face challenges in maintaining intimate contact between surfaces during the heating and cooling cycle, leading to issues with bonding and increased costs due to the use of adhesives and fasteners for joining thermoset and thermoplastic materials.

Innovation Solution

A method involving the use of a thermoplastic insert sized larger than the tolerance gap between components, which is heated and pressured to fill the gap, with optional reinforcement materials like wire mesh or fiber materials, and supported to maintain direct contact during welding, allowing for improved bonding without adhesives or fasteners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If thermoplastic welding is used to join rotor blade components, then manufacturing cost is reduced and weight is decreased by eliminating adhesives and fasteners, but maintaining intimate contact between surfaces during heating and cooling becomes difficult

Engineering Contradiction:
Improvemanufacturing costVSAvoidintimate contact between surfaces
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The method applies pressure to the interface before and during heating to pre-establish intimate contact between the thermoplastic components. This preliminary action ensures that when the thermoplastic material becomes soft and flowable due to heating, the surfaces remain in close contact, enabling effective welding without gaps or voids.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The welding process utilizes parameter changes by heating the thermoplastic material to transition it from a rigid state to a soft, flowable state. This temperature-induced parameter change allows the material to conform to the interface geometry and fill gaps, while the applied pressure maintains contact throughout the process.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If thermoplastic components are used instead of thermoset materials, then ease of joining is improved through thermoplastic welding, but maintaining surface contact during the welding cycle becomes more challenging

Engineering Contradiction:
Improveease of joiningVSAvoidbonding quality
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

Pressure is applied to the interface before heating begins and is maintained throughout the heating and cooling cycles. This preliminary and continuous pressure ensures that the thermoplastic components remain in intimate contact despite the softening and flow of the material during welding, resulting in reliable bonds.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The method replaces traditional mechanical joining systems (adhesives and fasteners) with a thermally-activated welding process. By using heat to soften the thermoplastic material and applying pressure simultaneously, the process achieves reliable joining without the need for separate adhesive application or fastener installation steps.

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

3Manufacturing precision

If pressure is applied to maintain contact between components during welding, then bonding quality is improved, but component distortion may occur

Engineering Contradiction:
Improvebonding qualityVSAvoidcomponent distortion
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The pressure is applied in a controlled manner before and during heating, allowing the components to be pre-positioned and stabilized. This preliminary action ensures proper alignment is established before the thermoplastic material softens, reducing the risk of distortion while maintaining bonding quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The process carefully controls the temperature and pressure parameters to achieve welding without excessive distortion. By gradually heating the material and adjusting pressure levels throughout the cycle, the method maintains bonding quality while minimizing shape changes in the components.

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 enhances the bonding quality and reduces manufacturing costs by ensuring intimate contact between components, improving the structural integrity and weight efficiency of wind turbine rotor blades.

Implementation Method 1

heating the insert and the first and second components such that the insert begins to flow

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

applying pressure to the interface such that the insert and the first and second blade components remain substantially in direct contact with each other at the interface

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

welding the insert and the components together at the interface, wherein the heat and the applied pressure maintains the insert and the first and second substantially in direct contact during welding

Methodology Applied
Scientific EffectThermoplastic welding: Welding

Data Source

PatentEP3787879B1Method of joining rotor blade components using thermoplastic welding
Publication Date: 2023.04.12 LM WIND POWER AS
  • EP3787879B1 patent drawingFigure 1
  • EP3787879B1 patent drawingFigure 2
  • EP3787879B1 patent drawingFigure 3

AI summary

The present disclosure is directed to methods for joining rotor blade components using thermoplastic welding. The method includes arranging a first thermoplastic component and a second thermoplastic component together at an interface, determining a size of a tolerance gap between the first and second components at the interface, placing a thermoplastic insert between the first and second components at the interface, the insert being larger than the tolerance gap, heating the insert and the first and second components such that the insert begins to flow so as to fill the tolerance gap between the first and second components, applying pressure to the interface such that the insert and the first and second blade components remain substantially in direct contact with each other at the interface, and welding the insert and the first and second components together at the interface, wherein the heat and the applied pressure between the insert and the first and second components at the interface maintain the insert and the first and second substantially in direct contact at the interface during welding.