New technique takes the heat out of 3D printing process

Researchers from the University of Nottingham and UC Berkeley have developed a new chemistry approach to stabilize Volumetric Additive Manufacturing (VAM) by controlling the heat generated during the printing process. By incorporating Reversible Addition Fragmentation chain Transfer (RAFT) polymerization, the team successfully mitigated the thermal spikes that typically cause distortions and limit the scale of VAM-produced objects. This advancement is significant for the additive manufacturing sector as it enhances precision and material functionality while maintaining the high-speed, layerless benefits of volumetric printing.

Volumetric Additive Manufacturing (VAM) represents a shift from traditional layer-by-layer 3D printing, utilizing light patterns to solidify entire structures within a liquid resin in seconds or minutes. While this method offers high speeds and eliminates the delamination issues common in sequential deposition, it has historically been hindered by the exothermic nature of the chemical reaction. According to the research published in Nature Communications, internal temperatures can rise by more than 60°C (140°F), leading to uncontrolled reactions, loss of detail, and significant structural distortions that restrict the size of the final parts.

To address these thermal challenges, a team led by Eduards Krumins and Professor Derek Irvine introduced Reversible Addition Fragmentation chain Transfer (RAFT) polymerization into the resin formulation. Krumins explains that RAFT acts as a built-in regulator that slows and stabilizes material formation, preventing the sudden heat spikes that compromise print quality. This chemical modification allowed the researchers to demonstrate improved efficiency and precision, including the ability to print multiple components simultaneously with gaps as small as approximately 150 micrometers, a notable improvement over standard VAM techniques.

Beyond thermal stability, the integration of RAFT chemistry ensures that printed objects retain reactive sites, allowing for post-processing enhancements such as the application of anti-fouling or antibacterial coatings. This versatility opens new doors for functionalized materials in sectors like healthcare and industrial manufacturing. Professor Irvine noted that the research is a step change for the industry, unlocking previously unreachable designs and functions. The team is currently exploring ways to scale the process for larger industrial applications and specialized fields such as bioprinting.