Core-Shell FDM Filaments for Optical Property Control

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Solution Overview

Problem

Existing 3D printing methods, particularly FDM, lack the ability to produce items with controllable optical effects such as transmissivity, scattering, and color variation, and the materials used, like photo-curable polymers, have low thermal conductivity and stability issues for injection molding applications.

Innovation Solution

A method using fused deposition modeling with core-shell filaments, where the core and shell materials have different melting temperatures, allowing controlled temperature manipulation in the nozzle to achieve spatially varying optical properties, enabling layers with different reflectivity, transmission, and light conversion without multiple printer heads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If photo-curable materials are used in 3D printing, then smooth surfaces can be produced, but the materials have low thermal conductivity and stability issues

Engineering Contradiction:
Improvesurface smoothnessVSAvoidmaterial stability
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent uses composite materials consisting of a thermoplastic matrix combined with photo-curable resin. This composite approach allows the material to exhibit both the smooth surface quality of photo-curable materials and the thermal stability and conductivity of thermoplastics, resolving the contradiction between surface quality and material reliability

Inventive Principle:
Principle #40Composite materials

2Device complexity

If a single nozzle is used for 3D printing, then device complexity is reduced, but the ability to produce items with varying optical properties is limited

Engineering Contradiction:
Improvenumber of printer headsVSAvoidoptical property control
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic temperature control of the nozzle, allowing the printing temperature to vary during the printing process. This dynamic approach enables a single nozzle to deposit material with different optical properties (translucent, transparent, opaque) at different locations by adjusting temperature, thereby achieving versatility without increasing device complexity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the temperature parameter of the nozzle during printing to control the optical properties of the deposited material. By varying temperature, the same nozzle can produce material with different degrees of transparency and optical characteristics, resolving the contradiction between device simplicity and functional versatility

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multiple materials with different optical properties are deposited, then optical control is improved, but the printing process complexity increases

Engineering Contradiction:
Improveoptical property variationVSAvoidprinting process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent employs periodic action by oscillating or varying the nozzle temperature during the printing process. This periodic temperature variation allows the deposition of material with different optical properties in a systematic manner, achieving optical control without requiring multiple nozzles or complex material handling systems

Inventive Principle:
Principle #19Periodic 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

Enables 3D printed items with controlled optical properties, allowing for varying colors and reflectivity through a single nozzle, enhancing the visual appearance and functionality of printed objects.

Implementation Method 1

the core and shell materials have different melting temperatures, allowing controlled temperature manipulation in the nozzle

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

different melting temperatures, allowing controlled temperature manipulation in the nozzle to achieve spatially varying optical properties

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

enabling layers with different reflectivity, transmission, and light conversion

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 4

enabling layers with different reflectivity, transmission, and light conversion

Methodology Applied
Scientific EffectLight transmission:

Data Source

PatentEP4415949B13D printed material having color and/or reflectivity control
Publication Date: 2026.04.08 SIGNIFY HOLDING BV
  • EP4415949B1 patent drawingFigure 1A~1B
  • EP4415949B1 patent drawingFigure 1C~2B(III)
  • EP4415949B1 patent drawingFigure 2C(I)~2D(IV)

AI summary

The invention provides a method for producing a 3D item (1) by means of fused deposition modelling using a fused deposition modeling 3D printer (500) comprising a printer nozzle (502), wherein the 3D item (1) comprises one or more layers (322) of 3D printed material (202), the method comprising a 3D printing stage comprising:- providing 3D printable material (201) to the printer nozzle (502), wherein:- the 3D printable material (201) comprises 3D printable core material (2101) and 3D printable first shell material (2201); - the 3D printable core material (2101) comprises a core thermoplastic material (2111) having a core thermoplastic material melting temperature Tmc1; - the 3D printable first shell material (2201) comprises a first shell thermoplastic material (2211) having a first shell thermoplastic material melting temperature Tms1; wherein Tmc1>Tms1;- the 3D printable first shell material (2201) has a 3D printable first shell material optical property, the 3D printable core material (2101) has a 3D printable core material optical property different from said 3D printable first shell material optical property; - controlling a temperature Tdm of the 3D printable material (201) in the printer nozzle (502) according to a scheme wherein during a first time period tp1: Tmc1> Tdm >Tms1applies and wherein during a second time period tp2: Tdm > Tmc1 applies.