Composite Material Molding Surface Finish Control

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Solution Overview

Problem

The existing techniques for molding composite materials, such as those described in JP 2014-173053 A, face challenges in achieving a smooth surface finish due to resin flow during thermoforming, leading to unevenness and distortion in the final product.

Innovation Solution

A method where the curing of a first resin with photocuring properties is completed before initiating the curing of a second resin with thermosetting properties in adjacent layers, using light irradiation for the first resin and heat for the second resin to control the curing process, thereby preventing resin flow and maintaining fiber orientation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If resin is impregnated in base material and thermoformed, then composite material is formed, but resin flows during thermoforming causing disturbance in base material and surface unevenness

Engineering Contradiction:
Improvecomposite material formationVSAvoidsurface finish
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The surface layer resin is cured by light irradiation before the internal layer resin is cured by heat. This preliminary curing of the surface layer prevents resin flow and base material disturbance during the subsequent thermoforming process, while still allowing the internal layers to be properly formed through heat curing.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If resin is cured by heat during thermoforming, then composite material is formed, but resin flow generates disturbance and unevenness in surface

Engineering Contradiction:
Improvecomposite material formationVSAvoidsurface uniformity
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The invention changes the curing parameter from heat-only to a combination of light irradiation for the surface layer and heat for the internal layers. This parameter change allows the surface layer to be cured at lower temperatures that prevent resin flow, while the internal layers still achieve proper curing through heat.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If light irradiation is used to cure surface layer resin, then resin flow is suppressed and fiber orientation is maintained, but curing of internal layers requires additional heat treatment

Engineering Contradiction:
Improvefiber orientationVSAvoidcuring process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention segments the curing process into two distinct stages: light irradiation for the surface layer and heat treatment for the internal layers. This segmentation allows each layer to be cured with the most appropriate method, preventing resin flow at the surface while ensuring complete curing throughout the composite material.

Inventive Principle:
Principle #1Segmentation

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 ensures a good appearance and surface quality by suppressing resin flow and maintaining fiber orientation, enhancing the durability and peeling strength of the composite material while preventing wrinkles and irregularities.

Implementation Method 1

The first resin is provided with a photocuring property. The first resin is cured by irradiating the first composite material with light

Methodology Applied
Scientific EffectPhotocuring: Photopolymerisation

Implementation Method 2

The second resin is provided with a thermosetting property. The second resin is cured by heating the second composite material

Methodology Applied
Scientific EffectThermosetting: Heating

Data Source

PatentEP3611004B1Method for molding composite materials
Publication Date: 2021.09.22 NISSAN MOTOR CO LTD
  • EP3611004B1 patent drawingFigure 1
  • EP3611004B1 patent drawingFigure 2A~2C
  • EP3611004B1 patent drawingFigure 2D~2F

AI summary

[Problem] To provide a molding method for composite materials with which it is possible to obtain a good appearance. [Solution] The method for molding a composite material (prepreg sheet 10) is a method in which the prepreg sheet 10, made by impregnating a base material (carbon fibers 11) with resin (matrix resin 12), is stacked and molded. In this method for molding the prepreg sheet 10, the curing of a first matrix resin 12P contained in a first prepreg sheet 10P is completed before starting the curing of a second matrix resin 12Q contained in a second prepreg sheet 10Q that is adjacent to the first prepreg sheet 10P of the surface layer.