Indexed Prepreg Composite Sheets for Fiber Alignment

Solution Overview

Problem

The existing methods for manufacturing laminated composite articles using prepreg composite materials face challenges in achieving precise alignment of reinforcement fibers, leading to misalignment and suboptimal strength and stiffness due to the tacky nature of the prepreg material, which increases process cycle time and cost.

Innovation Solution

A system and method for making indexed prepreg composite sheets involving a conveyor system, region forming apparatus, and calendaring apparatus to form discrete regions in the resin film layer, followed by replacing non-impregnated regions with indexing openings, allowing for precise alignment of fibers using a guide pattern, thereby improving fiber orientation accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If manual stacking of prepreg charges is used to achieve fiber alignment, then fiber orientation accuracy can be improved, but process cycle time and manufacturing cost increase

Engineering Contradiction:

Improvefiber alignment accuracyVSAvoidprocess cycle time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-forming charges to the exact shape of the final part before stacking, and by creating indexing features (such as tabs or notches) on each charge during the forming process. These indexing features enable automatic alignment during stacking, eliminating the need for time-consuming manual alignment while ensuring precise fiber orientation accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the manual mechanical stacking process with an automated stacking system that uses the pre-formed indexing features on charges. The automated system mechanically guides charges into correct positions using fixtures or conveyors that align with the indexing features, substituting human skill and time with automated mechanical guidance while maintaining alignment precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If manual stacking of prepreg charges is used to achieve fiber alignment, then fiber orientation accuracy can be improved, but manufacturing cost increases

Engineering Contradiction:

Improvefiber alignment accuracyVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-forming charges to the exact shape of the final part before stacking, and by creating indexing features (such as tabs or notches) on each charge during the forming process. These indexing features enable automatic alignment during stacking, eliminating the need for time-consuming manual alignment while ensuring precise fiber orientation accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the manual mechanical stacking process with an automated stacking system that uses the pre-formed indexing features on charges. The automated system mechanically guides charges into correct positions using fixtures or conveyors that align with the indexing features, substituting human skill and time with automated mechanical guidance while maintaining alignment precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If prepreg material is used with tacky properties for easy handling, then ease of operation is improved, but fiber alignment precision deteriorates due to edge misalignment

Engineering Contradiction:

Improvehandling easeVSAvoidcharge edge alignment

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-forming charges to the exact shape of the final part before stacking, and by creating indexing features (such as tabs or notches) on each charge during the forming process. These indexing features enable automatic alignment during stacking, eliminating the need for time-consuming manual alignment while ensuring precise fiber orientation accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the manual mechanical stacking process with an automated stacking system that uses the pre-formed indexing features on charges. The automated system mechanically guides charges into correct positions using fixtures or conveyors that align with the indexing features, substituting human skill and time with automated mechanical guidance while maintaining alignment precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution enables accurate alignment of fibers in laminated composite articles, reducing manufacturing time and cost by ensuring precise fiber orientation, thus enhancing the compliance with design specifications for strength and stiffness.

Implementation Method 1

a calendaring apparatus disposed downstream from the forming apparatus in the machine direction. The calendaring apparatus is configured to form a precursor prepreg composite sheet by impregnating the fiber reinforcement with the resin film layer

Methodology Applied

Scientific EffectImpregnation: Absorption (physical)

Data Source

PatentUS10081119B2Systems and methods for making indexed prepreg composite sheets and laminated composite articles

Publication Date: 2018.09.25 THE BOEING CO

AI summary

A method of making an indexed prepreg composite sheet is disclosed. The method comprises forming discrete regions in a resin film layer. The discrete regions are arranged in an indexing pattern. The method also includes forming a precursor prepreg composite sheet by impregnating a fiber reinforcement with the resin film layer having a viscosity. The discrete regions of the resin film layer form non-impregnated regions of the precursor prepreg composite sheet. The method additionally includes replacing the non-impregnated regions of the precursor prepreg composite sheet with indexing openings.