RTM Molding Device with Surface Layer for Thick Composite Impregnation

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Solution Overview

Problem

The RTM molding method faces challenges with resin impregnation in large or thick members, leading to non-impregnated regions and fiber wrinkling, especially when using high-viscosity resins, which are desirable for structural toughness and precision.

Innovation Solution

The RTM molding device incorporates a surface molding layer and resin diffusion portion with strategically sized and shaped through-holes to facilitate rapid resin diffusion and discharge across the entire surface of the fiber-reinforced base material, preventing fiber wrinkling and ensuring dimensional precision, using punched metal for rigidity and ease of cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If resin is injected from one end through to the other end of the fiber-reinforced base material, then the molding process is simple, but the impregnation time becomes very long and non-impregnated regions occur in large or thick members

Engineering Contradiction:
Improvemolding process complexityVSAvoidimpregnation time
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The invention divides the resin injection system into multiple injection ports distributed across the molding die, rather than using a single injection port. This segmentation allows resin to be injected at multiple locations simultaneously, reducing the distance resin must travel through the fiber-reinforced base material and significantly decreasing impregnation time while avoiding non-impregnated regions in large or thick members

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from one-dimensional resin flow (from one end to the other) to two-dimensional or three-dimensional resin distribution by positioning multiple injection ports at different locations on the molding die. This dimensional change enables resin to penetrate the fiber-reinforced base material from multiple directions simultaneously, dramatically improving impregnation efficiency

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If injection pressure is increased to raise the resin injection rate and shorten impregnation time, then the impregnation speed increases, but pressure loss increases and fiber wrinkling may occur

Engineering Contradiction:
Improveresin injection rateVSAvoidfiber wrinkling
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

By segmenting the injection system into multiple ports, the resin injection load is distributed across multiple locations. This allows for lower injection pressure at each port while maintaining high overall injection rate, preventing the pressure-related harmful effects such as fiber wrinkling that occur with high single-point injection pressure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces an intermediate resin distribution system (including resin distribution channels and porous plates) between the injection ports and the fiber-reinforced base material. This intermediary system evenly distributes resin from multiple injection ports, reducing localized pressure peaks that cause fiber wrinkling while maintaining efficient impregnation

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If high-viscosity resin is used to achieve structural toughness and precision, then the molded body has superior mechanical properties, but the impregnation process becomes difficult and non-impregnated regions occur

Engineering Contradiction:
Improvestructural toughnessVSAvoidimpregnation difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

Multiple injection ports enable high-viscosity resin to be injected at multiple locations simultaneously, reducing the travel distance and resistance the resin must overcome. This segmentation makes it feasible to use high-viscosity resins that provide superior structural toughness without suffering from incomplete impregnation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The resin distribution system (channels and porous plates) acts as an intermediary that facilitates the flow of high-viscosity resin into the fiber-reinforced base material. The porous plate structure provides capillary action and surface area that helps overcome the high viscosity, enabling thorough impregnation while maintaining the use of toughness-enhancing high-viscosity resins

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 configuration allows for efficient and uniform resin impregnation of large or thick members in a short time, achieving superior toughness and precision without non-impregnated regions or fiber damage, even with high-viscosity resins, and simplifies the cleaning process by using durable punched metal components.

Implementation Method 1

evacuating the inside of the dies to a state of reduced pressure

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

resin diffusion portion, the through-holes formed in each layer connect with the through-holes formed in an adjacent layer to form a resin flow path

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 3

injecting a resin into the inside of the dies through a resin injection port

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP2682247B1RTM molding device, RTM molding method, and semi-molded body
Publication Date: 2018.11.21 MITSUBISHI HEAVY IND LTD
  • EP2682247B1 patent drawingFigure 1~2
  • EP2682247B1 patent drawingFigure 3~4
  • EP2682247B1 patent drawingFigure 5~6(b)

AI summary

The objective is to provide an RTM molding device and an RTM molding method by which even a large member and a thick plate member can be impregnated with a resin without causing non-impregnatlon, fiber meandering, etc., and a high-tough-ness and high-precise molded body can be obtained. In an RTM molding device (100), a fiber-reinforced base material (11) is provided on at least one side surface thereof with: a surface molding layer (4) which is arranged between the fiber-reinforced base material (11) and a molding die (1), comprises a plurality of through holes (7) formed therein, and has a stiffness so that when the in-side of the cavity is depressurized, the thickness does not substantially change under the pressure in a cavity; and a resin diffusion portion (5) which is located on the side of the surface molding layer (4) opposite to the side of the fiber-reinforced base material (11), and comprises a resin flow path formed to communicate with the plurality of through holes (7) of the surface molding layer (4).