3D Printing Shell Core Filling Segmentation

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Solution Overview

Problem

In three-dimensional modeling, filling the core portion with a fluid core material is challenging when it is large or has complex shapes with narrow parts, leading to difficulties in material flow and potential void generation due to high viscosity and hydrodynamic resistance.

Innovation Solution

A three-dimensional modeling method where the shell material and/or core material contains a reinforcing material, such as carbon fiber or glass fiber, and the lamination modeling direction is gravity-based, allowing stepwise modeling of the shell layer and sequential filling of the core material, with collective curing using active energy rays and thermal energy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the core portion is large or has complex shapes with narrow parts, then the three-dimensional modeling object can achieve desired geometry, but the material flow becomes difficult and void generation increases due to high viscosity and hydrodynamic resistance

Engineering Contradiction:
Improvecomplex shapeVSAvoidvoid generation
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The core material filling process is divided into multiple stages corresponding to different shell layer modeling steps. Instead of filling the entire core portion at once, the material is incrementally introduced as the shell layers are formed, breaking down the complex filling task into manageable segments that reduce hydrodynamic resistance and prevent void formation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shell layer is modeled in advance before the core material filling is completed. By forming the shell structure first and then progressively filling the core material, the system prepares the containment structure beforehand, allowing controlled material introduction that adapts to the evolving geometry and prevents defects.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If the core material is filled after shell layer modeling is completed, then the core portion can be filled, but the filling becomes difficult when the core portion is large or has complex shapes leading to potential void generation

Engineering Contradiction:
Improvecore material fillingVSAvoidvoid generation
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The filling process is segmented into multiple incremental steps rather than a single bulk operation. Core material is introduced in controlled amounts at different stages of shell layer formation, allowing the material to progressively occupy the core portion while maintaining flow control and preventing void entrapment in complex geometries.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Shell layers are preliminarily formed to create the containment structure before core material filling is finalized. This preliminary shell formation provides a defined boundary that guides the incremental material introduction, ensuring complete and defect-free filling of large or complex core portions.

Inventive Principle:
Principle #10Preliminary action

3Strength

If reinforcing material is added to shell material and/or core material, then the strength and rigidity of the modeling object are improved, but the material viscosity increases making filling more difficult

Engineering Contradiction:
ImprovestrengthVSAvoidmaterial flow
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The material introduction is segmented into controlled incremental steps, allowing viscous composite materials (containing reinforcing fibers) to be introduced gradually. This segmentation prevents overwhelming the flow system with high-viscosity material, enabling complete filling while maintaining the strength-enhancing composition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Shell layers are preliminarily formed to establish the structural framework before the viscous core material containing reinforcing materials is fully introduced. This preliminary structure provides guidance for the thick material flow, ensuring complete penetration into complex geometries while maintaining the desired reinforcement distribution.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If stepwise modeling of shell layer is performed with sequential core material filling, then complete curing is achieved, but the process time is extended

Engineering Contradiction:
Improvecuring completenessVSAvoidprocess time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The shell layer modeling and core material filling operations are merged into a coordinated integrated process. Instead of completing all shell modeling before any filling, or vice versa, the two operations proceed in synchronized steps, with filling occurring incrementally during shell formation. This merging optimizes the overall process time while ensuring complete curing of all materials.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Shell layers are preliminarily formed to establish the structural framework before core material filling is finalized, but the process allows overlapping operations. This preliminary shell formation enables subsequent filling and curing operations to proceed efficiently without requiring complete separation of steps, reducing total process time while maintaining curing completeness.

Inventive Principle:
Principle #10Preliminary action

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 simplifies the filling of core material into complex shapes, reduces void formation, and prevents separation of reinforcing materials by maintaining the core material in a fluid state during filling, ensuring complete curing and avoiding residual uncured shell material.

Implementation Method 1

the core material is curable from a fluid state to a non-fluid state by irradiation with active energy rays

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

the core material is curable from a fluid state to a non-fluid state by irradiation with active energy rays or by application of thermal energy

Methodology Applied
Scientific EffectThermal curing: Heating

Implementation Method 3

the lamination modeling direction is gravity-based, allowing stepwise modeling of the shell layer and sequential filling of the core material

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3750689B1Three-dimensional forming method
Publication Date: 2024.03.13 TORAY ENG CO LTD
  • EP3750689B1 patent drawingFigure 1~2
  • EP3750689B1 patent drawingFigure 3~4
  • EP3750689B1 patent drawingFigure 5~6

AI summary

The present invention addresses the problem that while a fluid core material is filled inside (core portion) of a shell layer, the filling of the core material becomes difficult. Specifically, a three-dimensional modeling method is provided in which an outer shell layer (shell layer) of a three-dimensional modeling object is first modeled using a shell material, and then an inside (core portion) of the modeled outer shell layer is modeled using a core material, wherein the shell layer is modeled by an additive manufacturing technology, and is modeled by dividing the modeling of the shell layer into multiple steps in a lamination modeling direction, the core material is curable from a fluid state to a non-fluid state by irradiation with an active energy ray or by application of heat energy, the core material is filled into the inside (the core portion) of the modeled shell layer for each modeling of the shell layer that has been divided into the multiple steps, the core material is correctively cured by the irradiation with the active energy ray or by the application of the heat energy after the multiple steps of the modeling of the shell layer and the filing of the core material into the core portion are all completed.