SLA (Stereolithography)
Stereolithography Apparatus
Definition
SLA (Stereolithography Apparatus) is the earliest patented 3D printing technology (1986). It works by using an ultraviolet laser to scan and cure liquid photopolymer resin layer by layer, building up the solid form. Later LCD/MSLA technology (using an LCD screen as the light source) is a derivative variant of SLA, operating on the same principle.
Simple Analogy
If FDM is like stacking frosting to create a 3D shape, SLA is like “pulling” an object out of a vat of liquid — each time only a thin layer of the liquid surface is cured, the platform lifts slightly, then the next layer is cured, until the entire object emerges from the liquid.
Why It Matters
SLA excels over FDM in precision and surface quality:
- Layer heights as low as 0.025 mm, 5-10 times finer than FDM (typically 0.12-0.28 mm). Printed parts have a smooth, injection-molded finish — barely visible layer lines.
- Exceptional detail reproduction, making it ideal for figurines, jewelry prototypes, dental models, and other scenarios demanding high precision.
- However, the downsides are significant: resin is expensive ($14-$55/kg), has strong fumes, requires post-processing (washing + post-curing), and prints degrade over time when exposed to light.
Practical Advice
SLA is for users who demand extreme surface detail. But if your primary needs are functional parts, large objects, or low-cost prototyping, FDM remains the more practical choice. For beginners wanting to try resin printing, we recommend starting with an LCD printer in the $140-$280 range (such as the Anycubic Photon Mono series), choosing low-odor resin (like eSun water-washable resin), and ensuring your workspace is well-ventilated.