Fiber-Reinforced Insert Injection Molding for Complex Shapes

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Solution Overview

Problem

Fiber-reinforced composite materials offer high strength and reduced weight but have limited design freedom, making it difficult to manufacture complex shapes as single components, which increases costs and weight due to the need for separate assembly of components.

Innovation Solution

An insert injection molding method using fiber-reinforced composite materials as inserts, where a support groove is formed on the insert and a support protrusion on the mold prevents deformation during injection molding, allowing for the creation of complex shapes with high strength and reduced weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a fiber-reinforced composite material is used to manufacture a bumper back-beam, then high rigidity and crashworthiness are obtained, but the freedom of design is limited and it is difficult to manufacture as a single product

Engineering Contradiction:
ImproverigidityVSAvoidfreedom of design
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The bumper back-beam is divided into two functional segments: a fiber-reinforced composite material insert providing structural strength and rigidity, and a plastic resin matrix providing design freedom and integration. This segmentation allows each material to fulfill its optimal function while being manufactured as a single integrated product through insert injection molding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining fiber-reinforced composite material (for strength) and plastic resin (for design flexibility). This composite approach allows the final product to simultaneously achieve high rigidity from the fiber insert and design freedom from the molded plastic components, resolving the contradiction between strength and ease of manufacture.

Inventive Principle:
Principle #40Composite materials

2Strength

If components are separately formed and assembled, then the fiber-reinforced composite material can be used, but the cost increases and weight-lightening effect is insufficient

Engineering Contradiction:
ImprovestrengthVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention merges the fiber-reinforced composite material insert and the plastic resin components into a single integrated bumper back-beam through insert injection molding. This combining eliminates separate assembly steps, reduces manufacturing complexity, and maintains both the strength benefits of fiber reinforcement and the design flexibility of molded plastics in one unified product.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the insert is placed in the injection mold without support structure, then the injection molding process is simple, but the insert is deformed during the injection molding process

Engineering Contradiction:
Improveprocess simplicityVSAvoidinsert shape stability
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Support protrusions on the injection mold act as intermediary elements between the insert and the molding process. These protrusions provide localized support at critical points during resin injection, preventing insert deformation without requiring a complex support structure. This intermediary approach maintains process simplicity while ensuring manufacturing precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of providing uniform support across the entire insert, the invention applies support protrusions only at specific critical locations on the mold where deformation is most likely to occur during resin injection. This local quality approach prevents insert deformation at key points while maintaining overall process simplicity and avoiding excessive support structures.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3296078B1Insert injection molding method using fiber-reinforced composite material,
Publication Date: 2019.04.03 LG HAUSYS LTD
  • EP3296078B1 patent drawingFigure 1
  • EP3296078B1 patent drawingFigure 2
  • EP3296078B1 patent drawingFigure 3

AI summary

The present invention relates to an injection molding method using a fiber-reinforced composite material as an insert, and an injection molded product, and provides an injection molding method comprising: a step of preparing a fiber-reinforced composite material having a high-strength fiber, which is an insert material, impregnated in a resin; an insert formation step of manufacturing an insert by molding the fiber-reinforced composite material into a preliminary shape; and an injection molding step of manufacturing an injection product by arranging the insert in an injection mold and injecting a resin.