FDM Core-Shell Printing With Thermally Conductive Wire Cores

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Solution Overview

Problem

Current 3D printing technologies, particularly FDM, struggle to produce thermally conductive heatsinks for luminaires due to the limited thermal conductivity of graphite-filled polymers and the high cost and logistical challenges of using metals, leading to increased costs and delivery delays.

Innovation Solution

A method involving fused deposition modeling (FDM) that combines a thermoplastic shell material with a core of thermally conductive wires, where the core component is fed through or adjacent to the nozzle, using materials like tin, copper, or graphite wires, and a flexible mantle to enhance thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If graphite filled polymers are used for heatsinks, then thermal conductivity is improved, but thermal conductivity remains insufficient (around 5W/m·K)

Engineering Contradiction:
Improvethermal conductivityVSAvoidheat dissipation performance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The invention uses a composite filament structure with a thermoplastic shell material and a core component containing multiple thermally conductive wires (copper, aluminum, or graphite) surrounded by a flexible mantle. This composite structure combines the structural benefits of polymers with the high thermal conductivity of metal wires, achieving thermal conductivity significantly higher than graphite-filled polymers alone.

Inventive Principle:
Principle #40Composite materials

2Temperature

If metal printing is used for heatsinks, then thermal conductivity is improved, but cost and delivery time worsen

Engineering Contradiction:
Improvethermal conductivityVSAvoidmanufacturing cost
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The invention merges FDM 3D printing technology with a specially designed core-shell filament structure to achieve metal-like thermal conductivity in a cost-effective manner. The thermoplastic shell material provides structural integrity while the embedded thermally conductive wires provide high thermal conductivity, eliminating the need for expensive metal printing processes.

Inventive Principle:
Principle #5Merging (Combining)

3Temperature

If metal printing is used for heatsinks, then thermal conductivity is improved, but delivery time worsens due to pre-ordering and storage requirements

Engineering Contradiction:
Improvethermal conductivityVSAvoiddelivery time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The invention enables on-demand manufacturing of heatsinks using standard FDM 3D printers with the specialized core-shell filament. This eliminates the need for pre-ordering and storing metal components, allowing heatsinks to be printed locally and immediately when needed, significantly reducing delivery time and supply chain dependencies.

Inventive Principle:
Principle #25Self-service

4Ease of manufacture

If thermoplastic shell material is heated to melting point for extrusion, then 3D printing is enabled, but thermal stress on core wires worsens

Engineering Contradiction:
Improve3D printing capabilityVSAvoidmechanical stress on wires
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention uses a flexible mantle material surrounding the thermally conductive wires in the core component. This flexible mantle protects the wires from excessive thermal stress during the extrusion process while allowing the shell material to be heated to its melting point for proper extrusion and bonding. The flexible mantle acts as a thermal buffer and mechanical protector.

Inventive Principle:
Principle #30Flexible shells and thin films

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 approach allows for the cost-effective and efficient production of thermally conductive 3D items with improved heat dissipation, maintaining structural integrity and reducing mechanical stress on the wires.

Implementation Method 1

a shell component comprising a thermoplastic 3D printable shell material having a shell melting temperature Tms and/or a shell glass transition temperature Tgs

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

a shell component comprising a thermoplastic 3D printable shell material having a shell melting temperature Tms and/or a shell glass transition temperature Tgs

Methodology Applied
Scientific EffectGlass transition:

Implementation Method 3

a core component comprising a plurality of N thermally conductive wires

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4457082B1An improved method for 3D printing of a thermally conductive 3D item
Publication Date: 2025.10.08 SIGNIFY HOLDING BV
  • EP4457082B1 patent drawingFigure 1~2
  • EP4457082B1 patent drawingFigure 3
  • EP4457082B1 patent drawingFigure 4

AI summary

The present invention relates to a method for manufacturing a 3D item (100) by means of fused deposition modelling (FDM), the method comprising the steps of: a) providing a shell component (5') comprising a thermoplastic 3D printable shell material having a shell melting temperature (Tms) and/or a shell glass transition temperature (Tgs); b) providing a core component (2') comprising a plurality of thermally conductive wires (3) and a flexible mantle (4) enclosing the plurality of thermally conductive wires (3); c) feeding the shell component (5) into a nozzle (6) of a 3D printer, the nozzle (6) having a nozzle temperature (Tn) being equal to or greater than the shell melting temperature (Tms) and/or the shell glass transition temperature (Tgs); d) a layer-wise depositing of the 3D printable shell material and the core component (2) to provide the 3D item (100) comprising a core-shell layer (100') of 3D printed material, wherein the 3D printed material comprises a core (102) comprising the core component, and shell (105) comprising 3D printed shell material, wherein the shell (105) at least partly encloses the core (102).