FRP Molding via Mold Slit and Low-Temperature Injection

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Solution Overview

Problem

Existing methods for manufacturing composite molded bodies with tape-like fiber-reinforced plastics (FRP) struggle to accurately form three-dimensional shapes and integrate them with thermoplastic resins in a single mold, often resulting in complications, fiber breakage, and inaccurate lamination, especially when dealing with continuous fibers or complex geometries.

Innovation Solution

A method involving the introduction of a tape-like FRP base material into a mold via a slit part, followed by injection of a molten thermoplastic resin to form the FRP into a three-dimensional shape within the mold, utilizing a slide core to secure the FRP and ensure precise integration, allowing for high-accuracy molding and simplification of the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If preheating is performed for stamping molding of CFRP, then the CFRP can be molded in a mold, but the fibers are broken or their orientation is disturbed

Engineering Contradiction:
Improvemoldability of CFRPVSAvoidfiber orientation accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the temperature parameter from high-temperature preheating to low-temperature processing. The mold temperature is maintained at 50°C or lower, and the CFRP is processed without conventional preheating, thereby preserving fiber orientation while enabling moldability. This parameter change resolves the contradiction by finding an alternative temperature regime that achieves both goals.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If a plurality of base materials are laminated or a base material is laminated at a predetermined position, then complex composite structures can be created, but the CFRP flows together with resin during injection making accurate lamination difficult

Engineering Contradiction:
Improvecapability for complex composite structuresVSAvoidlamination accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention performs preliminary action by pre-assembling multiple CFRP base materials at predetermined positions within the mold before resin injection. The base materials are laminated and positioned in advance, and then the mold is closed and resin is injected. This preliminary positioning prevents CFRP flow during injection and ensures accurate lamination at desired locations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention segments the molding process into distinct stages: (1) preliminary assembly and lamination of CFRP base materials at predetermined positions, (2) mold closure, and (3) resin injection. This segmentation allows each stage to be optimized independently, ensuring accurate lamination positioning while maintaining the capability for complex composite structures.

Inventive Principle:
Principle #1Segmentation

3Strength

If the CFRP base material is laminated by laser welding or press molding after manufacturing the injection molded article, then the CFRP can be joined to the molded article, but it is difficult to laminate to a three-dimensional shape portion

Engineering Contradiction:
Improvejoining strength of CFRP to molded articleVSAvoiddifficulty of lamination to three-dimensional shape
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The invention uses the mold cavity as an intermediary tool to achieve precise lamination of CFRP base materials to three-dimensional shape portions. The mold cavity provides a pre-formed three-dimensional surface that guides and conforms the CFRP during preliminary assembly, enabling accurate lamination to complex geometries before resin injection. This intermediary approach eliminates the difficulty of directly laminating to three-dimensional shapes while maintaining high joining strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables efficient and accurate formation of composite molded bodies with high joining strength and precision, preventing issues like fiber breakage and warping, while allowing for automation and simplification of the molding process, even with complex geometries.

Implementation Method 1

forming a tape-like fiber reinforced plastic (FRP) base material into a three-dimensional shape

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

integrating it with a thermoplastic resin

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP3398748B1Method for manufacturing composite molded body
Publication Date: 2020.09.23 TORAY INDUSTRIES INC
  • EP3398748B1 patent drawingFigure 1(A)~1(D)
  • EP3398748B1 patent drawingFigure 2~3
  • EP3398748B1 patent drawingFigure 4(A)~5

AI summary

A method for manufacturing a composite molded body is characterized by comprising: a first step of introducing an FRP base material into a mold via a slit part provided in the mold, and inserting the FRP base material along a mold cavity; and a second step of injecting a molten thermoplastic resin composition A into the mold cavity to form the FRP base material into a three-dimensional shape and integrate the injected thermoplastic resin composition A and the FRP base material. The method makes it possible to easily and accurately mold a composite molded body of which a desired portion is efficiently and accurately reinforced in the same mold.