Composite Rotor Blade Curing with Segmented Heated Mold

Solution Overview

Problem

Current manufacturing processes for composite rotor blades are limited in producing parts with large thickness variations, leading to non-uniform curing and structural issues such as wrinkling and porosity, which affect the strength and reliability of the blades.

Innovation Solution

The use of tooling with a rigid outer mold and a heated inner core, where the heated layer is made of thermally expandable material with embedded heating elements, allows for controlled temperature and pressure distribution across the blade, enabling uniform curing and bonding of carbon fiber composite layers with varying thicknesses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional manufacturing processes are used for composite rotor blades, then production is simpler, but the parts cannot achieve large thickness variations and suffer from non-uniform curing

Engineering Contradiction:

Improvethickness variation controlVSAvoidmold structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mold is divided into two distinct components: a rigid outer mold and a heated inner core. This segmentation allows each component to serve a specific function - the outer mold provides structural support while the inner core delivers controlled heating and pressure, enabling large thickness variations without compromising curing uniformity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The heated inner core is designed to provide localized heating and pressure distribution tailored to different regions of the composite blade. This allows each section of the blade, regardless of thickness variation, to receive optimal curing conditions, ensuring uniform curing across the entire part.

Inventive Principle:

Principle #3Local quality

2Reliability

If conventional curing processes are used, then the process is simpler, but structural issues such as wrinkling and porosity occur

Engineering Contradiction:

Improvestructural integrityVSAvoidcuring process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The curing process utilizes controlled changes in temperature and pressure parameters through the heated inner core. By dynamically adjusting these parameters, the process eliminates wrinkling and porosity while maintaining structural integrity, transforming a simple curing operation into a precisely controlled manufacturing process.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If uniform heating is applied to composite layers with varying thickness, then the heating process is simpler, but non-uniform curing occurs

Engineering Contradiction:

Improvecuring uniformityVSAvoidheating system complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The heated inner core is designed to provide localized heating and pressure distribution tailored to different regions of the composite blade. This allows each section of the blade, regardless of thickness variation, to receive optimal curing conditions, ensuring uniform curing across the entire part.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The curing process utilizes controlled changes in temperature and pressure parameters through the heated inner core. By dynamically adjusting these parameters, the process eliminates wrinkling and porosity while maintaining structural integrity, transforming a simple curing operation into a precisely controlled manufacturing process.

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 ensures consistent curing and bonding across the rotor blade, reducing wrinkling and porosity, and enhancing the structural integrity and repeatability of composite rotor blades with complex geometries.

Implementation Method 1

a heated layer (108) secured thereto. The heated layer defines a second mold surface and is formed of a thermally expandable material

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

A plurality of heating elements are embedded in the second mold

Methodology Applied

Scientific EffectConduction heating: Conduction (thermal)

Data Source

PatentUS8894791B1Composite rotor blade manufacturing method and apparatus

Publication Date: 2014.11.25 SKYWORKS GLOBAL INC

AI summary

Apparatus and methods are disclosed for manufacture of a composite structure, such as a composite rotor blade spar or composite rotor blade. A first mold may define a first mold surface and a second mold may include a rigid layer and a heated layer secured to the rigid layer and defining a second mold surface. A plurality of heating elements embedded in the second mold may be activated according to different temperature progressions to cure portions of the uncured composite rotor blade positioned coextensive therewith. In some embodiments, the second mold defines a root portion and first and second branch portions. A shear web placed between the branch portions may be bonded to a blade skin positioned within the mold. The rotor blade may include a rotor blade spar having leading and trailing edge fairings secured thereto or the blade spar may define a complete airfoil contour.