Perforated Caul Sheet Resin Flow Control

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Solution Overview

Problem

Resin infusion processes face challenges such as resin flow restriction, uneven resin distribution, surface finish issues, and complex tooling requirements, particularly in applications requiring aerodynamic surfaces and integrated components.

Innovation Solution

A perforated caul sheet with tailored perforation patterns and densities is used to control resin flow, eliminating the need for a peel ply and allowing direct placement of resin supply hardware, thereby optimizing resin distribution and simplifying tooling for complex components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a peel ply is used to protect the fiber component, then the fiber component is protected from direct resin contact, but the resin flow is restricted and infusion time increases

Engineering Contradiction:
Improvefiber component protectionVSAvoidinfusion time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention removes the peel ply layer from the resin infusion process. By eliminating this intermediate layer, resin can flow directly into the fiber component without restriction, significantly reducing infusion time while maintaining component protection through the vacuum bag system alone.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If resin supply components are located off the fiber component, then the component surface is not marked, but resin supply is limited and infusion distances increase

Engineering Contradiction:
Improvesurface finish qualityVSAvoidinfusion efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The vacuum bag serves multiple functions simultaneously: it protects the fiber component, creates the vacuum for resin infusion, and acts as the resin distribution media. This eliminates the need for separate resin supply components, allowing direct resin application onto the component surface without mark-off while maintaining efficient resin supply.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If a flexible peel ply and flexible resin distribution media are placed in contact with the fiber component, then the component is protected and resin is distributed, but the surface finish becomes rough

Engineering Contradiction:
Improvecomponent protectionVSAvoidsurface finish smoothness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention removes both the flexible peel ply and flexible resin distribution media from direct contact with the fiber component. Protection is maintained through the vacuum bag system, and resin distribution is achieved through the rigid vacuum bag conforming to the component shape, resulting in a smooth surface finish suitable for aerodynamic applications.

Inventive Principle:
Principle #2Taking out (Extraction)

4Manufacturing precision

If uniform resin distribution media is used, then resin is distributed evenly across the component, but resin starvation occurs in isolated areas

Engineering Contradiction:
Improveresin distribution uniformityVSAvoidcomplete infusion
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention uses a rigid vacuum bag that dynamically conforms to the component's three-dimensional shape, creating non-uniform resin distribution patterns that actively direct resin to isolated and hard-to-reach areas. This dynamic adaptation prevents resin starvation by ensuring all areas receive adequate resin flow, unlike static uniform distribution media.

Inventive Principle:
Principle #15Dynamics

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 approach reduces infusion time, ensures a smooth surface finish, and enables the resin infusion of complex parts with simplified tooling, improving infusion reliability and reducing scrap and labor costs.

Implementation Method 1

a vacuum is drawn which both compacts the fiber component and draws resin through the component

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

resin is drawn through the plurality of caul plate apertures using the general vacuum

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 3

The perforations may have a tapered cross section... controlling the flow of resin through a fiber component

Methodology Applied
Scientific EffectCapillary Action: Capillary Action

Data Source

PatentEP2749401B1Resin infusion of composite parts using a perforated caul sheet
Publication Date: 2018.08.22 THE BOEING CO
  • EP2749401B1 patent drawingFigure 1
  • EP2749401B1 patent drawingFigure 2~4
  • EP2749401B1 patent drawingFigure 5~7

AI summary

Resin infused composite parts (24) are fabricated using a caul sheet (26) having perforations (48) therein for optimizing the flow of resin (34) through the parts and allowing a simplified tooling and consumable arrangement for complex parts while achieving a smooth, aerodynamic caul-side or bag-side finish.