VAT Polymerization in 3D Printing: How UV Curing Sets It Apart

3D printing has evolved from simple air‑drying methods to sophisticated UV‑curing techniques. VAT polymerization is a leading example, using ultraviolet light to solidify resin and build parts with exceptional detail.

What Is VAT Polymerization?

In VAT polymerization, a vat of liquid photopolymer resin is filled before printing. The printer’s light source selectively cures the resin layer by layer, hardening it into the desired geometry. Unlike extrusion‑based printers, no material is deposited; the resin is already present and only cured.

Key variants include:

• Stereolithography (SLA)
• Digital Light Processing (DLP)
• Masked Stereolithography (MSLA)

VAT Polymerization vs. Fused Filament Fabrication (FFF)

The most noticeable difference is the feeding mechanism. FFF extrudes thermoplastic filament through a heated nozzle, building the part by laying down solid layers. VAT polymerization, in contrast, relies on a vat of liquid resin that is cured by UV light—no filament is involved.

Material-wise, FFF works with thermoplastics such as PLA, ABS, or PETG, while VAT polymerization uses UV‑sensitive photopolymer resins. These resins can achieve layer thicknesses as fine as 25 µm, enabling high‑resolution prints with smooth surfaces.

Only VAT polymerization employs UV curing, a feature that gives it an edge in industries that demand precision, such as dental, jewelry, and aerospace prototyping.