Researchers Tame Volumetric 3D Printing's Heat Problem With Built-In 'Regulator' Chemistry

The promise — and the catch — of printing whole objects at once

Traditional 3D printing builds parts layer by layer, a process that is reliable but slow and prone to weak seams between layers. Volumetric Additive Manufacturing (VAM) takes a radically different approach: instead of depositing material sequentially, it floods a vat of liquid resin with carefully patterned light and grows an entire object simultaneously, in seconds to minutes.

Because nothing is laid down in sequence, VAM sidesteps delamination entirely and can produce complex geometries that conventional methods struggle with. The trade-off has always been heat. The photochemical reaction that hardens the resin is exothermic, and inside a sealed vat temperatures can climb by more than 60°C. That heat spike sends the reaction out of control, distorting fine detail and capping how large an object can be.

A built-in 'regulator' for the reaction

A collaboration between the University of Nottingham's Faculty of Engineering and the University of California, Berkeley, has published a fix in Nature Communications. Rather than fighting the heat with hardware, the team changed the chemistry.

They introduced a technique called Reversible Addition–Fragmentation chain Transfer (RAFT) polymerisation into the VAM resin. In the words of research fellow Eduards Krumins, it acts like a built-in 'regulator' for the reaction — both slowing and governing how the material forms. That prevents sudden heat spikes and keeps the print stable and predictable.

What the new approach unlocks

The results were concrete. The team recorded a clear reduction in temperature build-up during printing and far fewer thermal instabilities that would otherwise warp a structure. They also demonstrated printing multiple parts at once with gaps as small as roughly 150 micrometres — a meaningful improvement over 'normal' VAM and a big step toward batch efficiency.

Just as important, the RAFT chemistry leaves reactive sites on the finished part. Those sites can be addressed after printing to add new functions — the researchers point to anti-fouling and anti-bacterial coatings as near-term examples.

Why it matters for the future

Professor Derek Irvine, who led the materials chemistry work, called it 'a step change in volumetric 3D printing: making it more stable, more versatile, while unlocking designs and functions that were previously out of reach.' The area he flags as most promising is medical — future bioprinting technologies that need both speed and biological functionality.

The team is now working on scaling the process for larger, practical industrial use. If that scaling holds, VAM could move from a fascinating lab curiosity toward a genuine alternative for high-throughput, high-complexity printing where layer-based methods hit a wall.