Foamed Fiber-Reinforced Molding for Thin-Wall Long-Flow Components

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Solution Overview

Problem

Fiber-reinforced injection-molded components with long flow paths and thin wall thicknesses face issues such as poor surface finish, reduced strength, and insufficient taper, with fibers aligning parallel to the flow path, leading to weak points of failure and rapid propagation of component failure.

Innovation Solution

Incorporating gas bubbles formed by a blowing agent into the injection-molded components, which disrupt the alignment of reinforcing fibers, causing them to align transversely to the flow direction, enhancing strength and elasticity, and controlling gas bubble formation for improved surface quality and reduced shrinkage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the wall thickness is reduced to less than 2 mm, then the component weight is reduced, but the strength and surface finish deteriorate

Engineering Contradiction:
Improvecomponent weightVSAvoidcomponent strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent introduces a foamed structure with controlled porosity (5-50% void volume) into the injection-molded component. This porous structure reduces the overall density and weight of the component while maintaining structural integrity through the foam matrix. The gas bubbles act as internal support structures that prevent collapse in thin-walled sections, enabling wall thicknesses of less than 2 mm without compromising strength.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent combines polymer matrix with gas bubbles to create a composite foamed material. This composite structure integrates the lightweight benefits of gas-filled voids with the structural properties of the polymer matrix, achieving a material that is both lightweight and mechanically sound for thin-walled applications.

Inventive Principle:
Principle #40Composite materials

2Area of stationary object

If the flow path length is increased, then the component can cover larger areas, but the fiber alignment becomes more uniform (parallel), reducing strength in perpendicular directions

Engineering Contradiction:
Improvecomponent coverage areaVSAvoidstrength perpendicular to flow path
Core Design Contradiction:
Area of stationary objectVSStrength

Solution Approach 1:

The gas bubbles in the foamed structure disrupt the continuous flow path of fibers, creating localized disturbances that cause fibers to deviate from perfect parallel alignment. This disruption is particularly effective in long flow paths, where bubbles act as obstacles that scatter and reorient fibers in multiple directions, improving transverse strength without limiting the overall component size.

Inventive Principle:
Principle #31Porous materials

3Weight of moving object

If the wall thickness is reduced, then the component weight is reduced, but shrinkage-related molding problems increase

Engineering Contradiction:
Improvecomponent weightVSAvoidmolding precision
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

The foamed structure with distributed gas bubbles compensates for shrinkage during cooling. The gas voids provide internal volume that can accommodate dimensional changes, reducing the stress and deformation associated with shrinkage in thin-walled sections. This maintains manufacturing precision while enabling reduced wall thickness.

Inventive Principle:
Principle #31Porous materials

4Strength

If gas bubbles are added to disrupt fiber alignment, then strength in transverse directions is improved, but the component complexity increases

Engineering Contradiction:
Improvestrength perpendicular to flow pathVSAvoidcomponent structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent employs a foamed structure where gas bubbles are generated in-situ during the injection molding process using blowing agents. This approach creates the desired fiber-disrupting porous structure without requiring additional manufacturing steps, molds, or assembly operations, thereby minimizing added complexity while achieving improved transverse strength.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent controls the properties of gas bubbles (size, distribution, concentration) by adjusting processing parameters such as blowing agent quantity, injection temperature, and pressure. This allows optimization of fiber disruption for strength improvement while maintaining manufacturability and avoiding excessive structural complexity.

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

The solution enables the production of components with higher strength, reduced weight, and improved surface finish, allowing for longer flow paths and thinner wall thicknesses without compromising structural integrity.

Implementation Method 1

The base body contains decomposition particles of a gas bubble-forming blowing agent

Methodology Applied
Scientific EffectDecomposition: Decomposition (biological)

Implementation Method 2

A plurality of gas bubbles and reinforcing fibers are embedded in the base body

Methodology Applied
Scientific EffectGas expansion: Bubble

Data Source

PatentEP4186672B1Elongated injection-molded component
Publication Date: 2026.03.11 POLLMANN INT
  • EP4186672B1 patent drawingFigure 1
  • EP4186672B1 patent drawingFigure 2~3
  • EP4186672B1 patent drawingFigure 4

AI summary

The present invention relates to a component (100) with an injection-molded base body (101), wherein the base body (101) has a wall thickness (d) of less than 1.9 mm and a plurality of gas bubbles (102) and reinforcing fibers (103) are embedded in the base body (101). The flow path length (FI) of the injection-molded base body (101) is greater than 300 mm.