How SLA Stereolithography Works in Rapid Prototyping

SLA technology is based on the photopolymerization principle of liquid photosensitive resin. Under ultraviolet light with a specific wavelength and intensity, the liquid resin rapidly polymerizes, its molecular weight increases sharply, and the material changes from a liquid state into a solid state.

In the SLA process, a laser beam scans the surface of a vat filled with liquid photopolymer resin. Under the control of a computer and a mirror system, the laser follows the required scanning path and selectively cures the resin wherever the light strikes.

At the beginning of the build, the working platform is positioned at a certain depth below the resin surface. The focused laser spot then scans the liquid surface point by point according to the digital model data, solidifying the required cross-section of the part. After one layer is completed, the uncured area remains in liquid form.

The platform then moves downward by one layer thickness, and a new layer of resin is spread across the surface. For higher-viscosity resins, a recoating mechanism is used to level the liquid surface before the next scan begins. The new layer is then cured and bonded firmly to the previous layer. This process is repeated layer by layer until the entire part is completed and a three-dimensional solid model is formed.