Rapid Additive Manufacturing of 3D Geometric Structures via Dual-Wavelength Polymerization

Area of Science:

• Polymer Chemistry
• Additive Manufacturing
• Photochemistry

Background:

• Photopolymerization enables 3D printing but is limited by speed and resolution.
• Dual-wavelength systems offer potential for advanced control over polymerization.
• Existing methods often struggle with fabricating complex internal structures efficiently.

Purpose of the Study:

• To develop and validate a dual-wavelength photopolymerization process for efficient volumetric fabrication.
• To optimize resin composition for controlled photocuring using distinct wavelengths.
• To demonstrate the fabrication of complex geometries with internal voids and reduced printing times.

Main Methods:

• A methacrylate-based resin was formulated with a photoinitiator (473 nm) and a photoinhibitor (365 nm).
• Concentrations of photoinitiator and photoinhibitor were optimized for depth of cure and wavelength-specific inhibition.
• Volumetric fabrication was performed using dynamic control of 365 nm and 473 nm light projection patterns.

Main Results:

• Optimized resin achieved full cure depth (4.6 mm) with 473 nm light alone.
• 365 nm light effectively inhibited polymerization, enabling the creation of voids.
• Complex structures were fabricated in 2 minutes, a significant reduction from 20 minutes with single-wavelength systems.

Conclusions:

• Dual-wavelength photopolymerization allows for precise control over resin curing and inhibition.
• This method enables rapid, multi-step fabrication of complex 3D objects with internal features.
• The developed process offers a substantial improvement in printing speed and complexity for additive manufacturing.