Researchers from University of California Santa Barbara and the Lawrence Livermore National Laboratory (LLNL) have developed a revolutionary 3D printing technique that creates two materials from one resin, potentially transforming additive manufacturing by eliminating the need for manual support removal. The breakthrough, published in ACS Central Science, demonstrates a single photoreactive resin that simultaneously produces solid objects and dissolvable structural supports depending on the type of light exposure during printing.
The innovative approach addresses one of the most challenging aspects of vat photopolymerisation—the time-consuming and often nerve-wracking process of manually removing temporary supports from intricate structures. By enabling two materials from one resin through selective light exposure, the research team has opened new possibilities for complex 3D printed applications including tissue engineering scaffolds, mechanical joints, and hinges.
Dual-Light System for Two Materials from one Resin
The research team, led by corresponding author Maxim Shusteff, developed a specialised 3D printer that emits both ultraviolet and visible light, allowing simultaneous printing of permanent objects and their temporary supports. This dual-light approach represents a significant advancement in vat photopolymerisation technology, which is known for its speed and high-resolution capabilities.
“Vat photopolymerization is known for its fast and high-resolution printing, but one of the most nerve-wracking parts after printing is manually removing supports for intricate interlocking and overhang structures. We are very excited that we can use simple chemistry to solve this issue.”
– Maxim Shusteff, one of the Authors of the research paper
The key innovation lies in the formulation of a single resin containing different monomers that respond to specific wavelengths of light. When exposed to visible light, acrylate monomers in the resin solidify to form dissolvable, anhydride-based support materials. Under UV light exposure, epoxy monomers harden into the permanent portion of the object, creating two distinctly different materials from one resin system.
This selective polymerization process eliminates the traditional two-step approach that requires dipping objects into separate resin batches for support structures. The conventional method adds time, expense, and complexity due to additional material requirements and the manual effort needed to remove temporary supports.
Innovative Chemistry and Safe Dissolution Process
The research team, including co-researcher Sijia Huang, formulated their breakthrough resin by mixing various components including acrylate/methacrylate and epoxy monomers alongside photoreactive substances that absorb both visible and UV light. This careful chemical composition enables the selective formation of two materials from one resin through controlled light exposure.
During testing, the researchers observed distinct material behaviours under different lighting conditions. The acrylate monomers responded exclusively to visible light, forming the dissolvable support structures, while epoxy monomers only hardened under UV light, creating the permanent object components. This wavelength-specific response is crucial for achieving precise control over which portions of the print become permanent versus temporary.
The dissolution process for removing support structures proved both efficient and environmentally friendly. Researchers simply placed completed objects in a sodium hydroxide solution at room temperature, revealing the permanent structures within 15 minutes. Importantly, the anhydride-based scaffolds degraded into non-toxic compounds, addressing safety concerns associated with traditional support removal methods.
Complex Structures Demonstrate Technology Potential
To validate their approach for creating two materials from one resin, the research team produced increasingly complex demonstration structures. These included a checkerboard pattern, a cross design, interlocking rings, a ball trapped within a cage, and two balls arranged in a helical configuration.
These test structures showcase the technology’s capability to produce intricate geometries that would be challenging or impossible to create through traditional manufacturing methods. The ability to print complex interlocking components in a single operation, with supports that dissolve cleanly away, opens new possibilities for mechanical assemblies, artistic creations, and functional devices.
The successful creation of these demonstration pieces validates the concept that two materials from one resin can effectively replace traditional multi-step printing processes. This advancement could significantly expand the range of applications for 3D printed objects, particularly in fields requiring complex internal structures or moving parts.
Implications for Advanced Manufacturing Applications
The breakthrough in creating two materials from one resin holds particular promise for tissue engineering applications, where biodegradable scaffolds must support cell growth while eventually dissolving harmlessly in the body. The technology could enable the creation of complex tissue scaffolds with integrated support structures that dissolve at controlled rates.
Mechanical applications including joints, hinges, and other moving assemblies could benefit from the ability to print fully functional mechanisms in a single operation. Traditional manufacturing of such components often requires assembly of multiple parts, whereas this approach could produce ready-to-use mechanical systems directly from the printer.
The research represents a significant step toward more efficient and versatile additive manufacturing processes, potentially reducing production times and costs while expanding the complexity of achievable designs.
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