Partially Polymerized Prepreg Drape Forming Without Intermediate Compaction

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Solution Overview

Problem

Current methods for manufacturing thermosetting composite parts require intermediate compaction to remove air and ensure layer alignment, which is time-consuming and complicates the process, and often necessitate polymerization under pressure in an autoclave.

Innovation Solution

A process involving partially polymerized pre-impregnated materials with a resin polymerization rate between 20% and 60%, allowing draping without intermediate compactions and potentially eliminating the need for autoclave polymerization, using a method that includes heating and pressing steps to manage porosity and viscosity for efficient draping and final polymerization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If intermediate compaction is performed during draping to remove air and ensure layer alignment, then manufacturing precision and reliability are improved, but productivity decreases due to time-consuming operations and process complexity

Engineering Contradiction:
Improvelayer alignmentVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The resin is partially polymerized in advance during prepreg storage, achieving a polymerization rate of 20-60% before draping. This preliminary action creates initial tackiness that maintains layer alignment during draping without requiring intermediate compaction operations, thereby eliminating time losses while ensuring manufacturing precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the polymerization rate parameter of the resin from <20% (conventional) to 20-60% (invented range). This parameter change transforms the resin's physical properties, providing sufficient tackiness for layer bonding during draping, which eliminates the need for intermediate compaction and improves productivity while maintaining layer alignment.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If intermediate compaction is performed to evacuate air from interfolds, then reliability of the laminate structure is improved, but device complexity increases due to additional equipment and process steps

Engineering Contradiction:
Improvelaminate structureVSAvoidprocess equipment
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The resin undergoes preliminary partial polymerization during storage, achieving 20-60% polymerization rate before draping. This creates initial tackiness that ensures reliable layer bonding during draping without requiring additional compaction equipment or intermediate compaction steps, thereby maintaining laminate reliability while simplifying device complexity.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If material is stored at -18°C to maintain low polymerization rate, then ease of manufacture and storage is improved, but energy consumption increases

Engineering Contradiction:
Improvematerial storageVSAvoidstorage energy
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The invention changes the polymerization rate parameter to 20-60%, which provides sufficient tackiness for draping at ambient temperature. This allows storage at room temperature instead of -18°C, maintaining ease of manufacture while dramatically reducing energy consumption for refrigeration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The resin undergoes preliminary partial polymerization to achieve 20-60% polymerization rate, which creates the necessary tackiness for draping. This preliminary action eliminates the need for cold storage, reducing energy consumption while maintaining ease of manufacture and handling.

Inventive Principle:
Principle #10Preliminary action

4Ease of operation

If heating is applied just before laying to increase resin tackiness, then ease of operation is improved, but energy consumption increases

Engineering Contradiction:
Improvedraping operationVSAvoidheating energy
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The resin is preliminarily partially polymerized during storage to achieve 20-60% polymerization rate, which creates sufficient tackiness for draping at ambient temperature. This eliminates the need for heating just before laying, maintaining ease of operation while reducing energy consumption.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the polymerization rate to 20-60%, which provides adequate tackiness for draping without requiring additional heating. This parameter change maintains ease of operation while eliminating the energy consumption associated with pre-heating before laying.

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 approach eliminates the need for intermediate compactions, reduces production time, and allows for storage at ambient temperature, enabling final polymerization outside the autoclave with improved air drainage and reduced energy consumption.

Implementation Method 1

a step of impregnating fibers with thermosetting resin and a step of partial polymerization of the resin at a rate of between 20 % and 60%

Methodology Applied
Scientific EffectPartial polymerization: Photopolymerisation

Implementation Method 2

a step of heating the deposited material to a temperature above the glass transition temperature of the prepreg state considered

Methodology Applied
Scientific EffectHeating above glass transition temperature: Heating

Implementation Method 3

a step of pressing the deposited material

Methodology Applied
Scientific EffectPressure application: Compression

Implementation Method 4

a step of cooling of the deposited material, making it possible to return to a temperature lower than the glass transition temperature of the pre-impregnated state considered

Methodology Applied
Scientific EffectCooling below glass transition temperature: Cooling

Data Source

PatentEP2911863B1Method for producing thermosetting composite parts by drape-forming of preimpregnated material
Publication Date: 2018.12.05 AIRBUS (SAS)
  • EP2911863B1 patent drawingFigure 1~2
  • EP2911863B1 patent drawingFigure 3

AI summary

The present invention relates to a method for manufacturing a partially polymerized, preimpregnated material, said method comprising: - a step of impregnation of fibres with thermosetting resin, and - a step of partial polymerization of the resin to a degree of between 10% and 60%. The invention also relates to the production of thermosetting composite parts by drape-forming of the preimpregnated material according to the following steps: - depositing the material in the form of strips, - heating the deposited material, to a temperature above the glass transition temperature of the preimpregnated state, - pressing the deposited material, and - cooling the deposited material, making it possible to return to a temperature below the glass transition temperature of the preimpregnated state under consideration.