Copper Nanoparticle-Tin Conductive Ink for Low-Cost 3D Printed Traces
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Solution Overview
Problem
Current electrically conductive inks for additive manufacturing, particularly for creating circuit traces, face challenges due to high resistance values and the high cost and susceptibility to oxidation of silver inks, while copper's high melting point makes it difficult to use effectively.
Innovation Solution
A conductive ink composition is developed using copper nanoparticles suspended in tin, with a manufacturing method that involves atomizing and dispersing the nanoparticles within a tin bath using sonification, resulting in a filament with superior conductive properties and lower costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silver is used as the conductive ink material, then electrical conductivity is improved, but cost and susceptibility to oxidation increase
Solution Approach 1:
The patent replaces expensive silver with copper, a cheaper alternative material. The copper-based conductive ink achieves acceptable electrical conductivity at lower cost, accepting that copper requires protective measures against oxidation rather than being inherently oxidation-resistant like silver.
Solution Approach 2:
The patent creates a composite conductive ink formulation combining copper particles with organic vehicles and additives. This composite approach allows optimization of both electrical conductivity and oxidation resistance through the synergistic combination of conductive copper particles and protective organic components.
2Ease of manufacture
If copper is used as the conductive ink material, then cost is reduced, but melting point increases making it difficult to use
Solution Approach 1:
The patent changes the physical state and size parameters of copper from bulk metal to nanoscale particles. This parameter change reduces the effective processing temperature needed, as copper nanoparticles can be deposited and sintered at lower temperatures than bulk copper, making the material more workable despite its inherently high melting point.
Solution Approach 2:
The patent segments copper into discrete nanoparticles rather than using bulk copper. This segmentation allows the material to be processed in a dispersed state at lower temperatures, with final consolidation occurring through controlled sintering or binding, thereby circumventing the high melting point limitation.
3Ease of manufacture
If conventional conductive inks are used, then manufacturing process is simple, but resistance values are unacceptable
Solution Approach 1:
The patent changes the particle size parameter of the conductive material to nanoscale dimensions. This parameter change increases the surface area to volume ratio, improving contact between particles and reducing overall resistance while maintaining compatibility with existing printing and deposition processes.
Solution Approach 2:
The patent replaces traditional metal-based conductive materials with nanoparticle-based formulations that can be delivered through standard inkjet or extrusion printing systems. This substitution maintains manufacturing simplicity while achieving superior electrical properties through enhanced particle distribution and contact.
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 ink achieves resistivity values comparable to silver inks, offering lower costs and improved conductive properties, with copper nanoparticles in tin providing a stable and efficient conductor for additive manufacturing.
Implementation Method 1
initiating ultrasound pulses
Implementation Method 2
creating a heat gradient with a higher heat location at the upper edge of the funnel and a cooler location at the bottom of the funnel
Implementation Method 3
heating the funnel to melt the white tin
Implementation Method 4
creating a heat gradient with a higher heat location at the upper edge of the funnel and a cooler location at the bottom of the funnel
Implementation Method 5
atomized and suspended in tin
Implementation Method 6
copper nanoparticles suspended in tin
Data Source
AI summary
Disclosed is a conductive ink composition and a manufacturing method thereof. The composition includes about 50 to about 99 wt % copper nanoparticles and about 1 to about 50 wt % tin. Copper nanoparticles are atomized and suspended in a tin bath, wherein the copper nanoparticles are evenly dispersed within the bath through sonification. The composition is cooled, extracted, and formed into a filament for use as a conductive ink. The ink has a resistivity of about 46.2×E−9 Ω*m to about 742.5×E−9 Ω*m. Once in filament form, the tin-copper mix will be viable for material extrusion, thus allowing for a lower cost, electrically conductive traces to be used in additive manufacturing.