Researchers Solve Mid-Print Overheating for Volumetric 3D Printing

Researchers from the University of Nottingham and the University of California, Berkeley, have developed a solution to a critical heat management issue in volumetric 3D printing, a technique that creates entire objects simultaneously rather than layer by layer. This method, known as Computed Axial Lithography (CAL), uses patterned light to solidify liquid resin, but the exothermic chemical reaction can cause overheating, leading to part deformation and limiting scalability.

The team introduced a class of chemical additives called RAFT agents into the resin. These agents act as internal regulators within the hardening reaction, slowing its pace and preventing uncontrolled heat spikes. This approach addresses the heat problem at the molecular level, ensuring a more stable and predictable printing process.

Testing revealed that even small amounts of the most effective RAFT agent additive reduced the temperature increase during printing from 59°C to 27°C, with a slightly larger concentration lowering it to just 3.5°C. This fix proved effective across various resin thicknesses, including a water-based gel suitable for medical applications.

With heat now controlled, the researchers demonstrated the ability to print multiple separate objects in the same vat simultaneously, spaced as close as 150 micrometers apart, without them fusing. This advancement also allows for printing intricate designs like interlocking parts, such as a freely rotating hinge, and nested objects in a single print. Furthermore, the treated material can undergo post-print treatments, like applying antibacterial coatings, opening possibilities for multi-functional printed objects.