Acoustophoretic Liquefaction for 3D Printing Ultrahigh-Viscosity Nanoparticle Suspensions

Area of Science:

• Materials Science
• Chemical Engineering
• Acoustic Engineering

Background:

• Digital Light Processing (DLP) 3D printing faces limitations with high-viscosity photopolymer resins.
• Processing ultrahigh-viscosity materials is crucial for creating advanced composites with enhanced mechanical properties.

Purpose of the Study:

• To introduce and evaluate an acoustic liquefaction approach to enhance resin flow in DLP 3D printing.
• To enable the processing of ultrahigh-viscosity silica particle-loaded silicone photopolymers.

Main Methods:

• Utilized acoustic liquefaction to modify the rheological properties of yield stress fluids.
• Employed numerical simulations to analyze acousto-mechanical coupling and predict flow velocities.
• Investigated the printing of highly loaded particle suspensions in complex geometries.

Main Results:

• Achieved processing of resins with apparent viscosity > 3700 Pa s at low shear rates.
• Predicted and achieved local resin flow velocities exceeding 100 mm s⁻¹.
• Successfully printed complex geometries using particle suspensions (ϕ = 0.23).
• Developed composites exhibited 2000% greater tensile toughness compared to neat photopolymer.
• Demonstrated improvements in printed feature resolution (>25%), printable object size (>50x), and build speed (>3x).

Conclusions:

• Acoustic liquefaction Digital Light Processing (AL-DLP) significantly enhances the processability of ultrahigh-viscosity resins.
• AL-DLP offers substantial improvements in resolution, build size, and speed for 3D printing.
• This technique facilitates the creation of mechanically robust, high-performance 3D printed composites.