Composite Honeycomb Panel Pre-Stabilization Co-Cure

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Solution Overview

Problem

Current composite honeycomb sandwich panels face issues with multiple cure cycles increasing production costs and defects due to bondline discrepancies, and co-cure processes often result in distortion, porosity, and resin leakage, making quality inspection challenging.

Innovation Solution

A one-step co-cure process involving pre-stabilization of the honeycomb core with a composite material and simultaneous curing of laminate skins at high pressure to minimize distortion and porosity, while allowing for ultrasonic inspection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple cure cycles are used to prevent honeycomb core deformation, then manufacturing precision is improved, but productivity decreases and manufacturing cost increases

Engineering Contradiction:
Improvehoneycomb core deformation controlVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The honeycomb core is pre-stabilized by impregnating it with adhesive before the co-cure process. This preliminary action prepares the core to withstand the high pressures of single-step co-curing without deforming, eliminating the need for multiple cure cycles and precuring steps while maintaining manufacturing precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent combines the core stabilization and skin curing operations into a single co-cure step. The pre-stabilized core and laminate skins are cured simultaneously in one autoclave cycle, merging multiple previously separate processes into one efficient operation that improves productivity without sacrificing quality.

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If single-step co-cure process is used to improve productivity, then manufacturing precision deteriorates due to distortion and porosity

Engineering Contradiction:
Improveproduction efficiencyVSAvoidpanel quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The honeycomb core undergoes pre-stabilization through adhesive impregnation before co-curing. This preliminary treatment ensures the core maintains its shape and provides proper support during the single-step co-cure process, preventing distortion and porosity formation while enabling high productivity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent optimizes curing parameters including applying high pressure (50-150 psi) and controlling temperature (100-200°F) during the co-cure cycle. These parameter changes ensure complete resin curing while preventing resin leakage into core cells and minimizing porosity, achieving both high productivity and manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If high pressure is applied during co-cure to reduce porosity, then manufacturing precision is improved, but the honeycomb core may deform

Engineering Contradiction:
Improveporosity controlVSAvoidhoneycomb core shape
Core Design Contradiction:
Manufacturing precisionVSShape

Solution Approach 1:

The honeycomb core is pre-stabilized with adhesive that cures to form a rigid structure. This preliminary action strengthens the core to withstand high curing pressures without deforming, enabling the application of 50-150 psi during co-cure to eliminate porosity while maintaining core shape integrity.

Inventive Principle:
Principle #10Preliminary action

4Shape

If low cure pressure is used to prevent core deformation, then shape is preserved, but porosity increases in composite skins

Engineering Contradiction:
Improvehoneycomb core shapeVSAvoidskin porosity
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The core is pre-stabilized with adhesive before co-curing, creating a rigid structure that can withstand high pressures. This enables the use of 50-150 psi during curing to produce porosity-free skins while the pre-stabilized core prevents deformation, resolving the contradiction between pressure level and quality outcomes.

Inventive Principle:
Principle #10Preliminary action

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 produces high-strength composite panels with minimal porosity, no resin leakage, and reduced distortion, facilitating cost-effective and inspectable composite panels with improved structural performance and quality.

Implementation Method 1

curing the pre-stabilizing material

Methodology Applied
Scientific EffectCuring:

Implementation Method 2

curing the pre-stabilizing material; curing said at least one laminate skin

Methodology Applied
Scientific EffectThermal energy: Heating

Implementation Method 3

bonding said at least one laminate skin to opposite sides of said pre-stabilizing material

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 4

curing said at least one laminate skin to opposite sides of said pre-stabilizing material substantially simultaneously at a pressure sufficient to minimize porosity in said composite panel

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2070694B1Composite panel and method of manufacturing the same
Publication Date: 2016.04.13 THE BOEING CO
  • EP2070694B1 patent drawingFigure 1
  • EP2070694B1 patent drawingFigure 2
  • EP2070694B1 patent drawingFigure 3

AI summary

A method of manufacturing a composite panel (10) is described. The method includes pre-stabilizing a honeycomb core with at least one layer of a pre-stabilizing material, surrounding the honeycomb core with at least one composite laminate skin layer (16,18), and curing the at least one composite laminate skin layer (Fig.3).