Variable Hardness Caul Body for Composite Curing

Solution Overview

Problem

Caul plates struggle to adequately conform to composite structures with complex geometries, leading to uneven pressure distribution during the curing process, which can result in suboptimal surface finishes and increased post-curing processing requirements.

Innovation Solution

A caul body comprising a laminate with varying thickness carbon and silicone layers, where the silicone layers define the outer surface and the carbon layers have different hardness values in distinct regions, allowing for better pressure distribution and conformity to complex shapes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a caul plate with uniform thickness is used, then the manufacturing process is simple, but the pressure distribution is uneven on complex geometries

Engineering Contradiction:

Improvecaul plate manufacturing simplicityVSAvoidpressure distribution uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The caul body incorporates regions of different hardness values within its structure. Specifically, it includes a first region with a first hardness value and a second region with a second hardness value that is less than the first hardness value. This local differentiation allows the caul body to adapt to complex geometries while maintaining manufacturing feasibility through a layered laminate construction.

Inventive Principle:

Principle #3Local quality

2Device complexity

If a caul plate with uniform hardness is used, then the device structure is simple, but the conformity to complex geometries is inadequate

Engineering Contradiction:

Improvecaul plate structure simplicityVSAvoidconformity to complex geometries

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The caul body incorporates regions of different hardness values within its structure. Specifically, it includes a first region with a first hardness value and a second region with a second hardness value that is less than the first hardness value. This local differentiation allows the caul body to adapt to complex geometries while maintaining manufacturing feasibility through a layered laminate construction.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The caul body is constructed as a laminate composite structure comprising at least one carbon layer and at least one silicone layer. The carbon layers provide structural integrity and varying hardness through thickness modulation, while the silicone layers provide conformability and pressure distribution. This composite approach enables the caul body to achieve both structural simplicity and geometric adaptability.

Inventive Principle:

Principle #40Composite materials

3Manufacturing precision

If a caul body with varying carbon layer thickness is used, then the pressure distribution improves, but the manufacturing complexity increases

Engineering Contradiction:

Improvepressure distribution uniformityVSAvoidcaul body structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The caul body is constructed as a laminate composite structure comprising at least one carbon layer and at least one silicone layer. The carbon layers provide structural integrity and varying hardness through thickness modulation, while the silicone layers provide conformability and pressure distribution. This composite approach enables the caul body to achieve both structural simplicity and geometric adaptability.

Inventive Principle:

Principle #40Composite 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

The caul body effectively distributes pressure and conforms to complex geometries, improving surface finishes and reducing the need for additional post-curing processing, particularly in regions with sharp bends or curves.

Implementation Method 1

the at least one silicone layer defining an outer surface of the laminate, the silicone layers defining the outer surface to abut against the composite structure

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a thickness of the at least one carbon layer in the first region being greater than a thickness of the at least one carbon layer in the second region, the first region having a hardness value greater than a hardness value of the second region

Methodology Applied

Scientific EffectHardness variation through thickness:

Implementation Method 3

curing the uncured composite structure covered by the caul body with pressure and heat to form a first composite region and a second composite region of the composite structure

Methodology Applied

Scientific EffectCuring:

Data Source

PatentUS11155047B2Caul body and a method for forming a composite structure

Publication Date: 2021.10.26 TEXTRON INNOVATIONS INC

AI summary

A caul body for forming a composite structure comprises a laminate having at least one carbon layer and at least one silicone layer. The at least one silicone layer defines an outer surface of the laminate. The laminate has a first region and a second region. A thickness of the at least one carbon layer in the first region is greater than a thickness of the at least one carbon layer in the second region. The first region has a hardness value greater than a hardness value of the second region.