SLA Printing: Complete Guide to Stereolithography 3D Printing
SLA printing (Stereolithography) was the first 3D printing technology ever invented, and it remains one of the most precise methods available today. Using UV light to cure liquid resin layer by layer, SLA produces parts with incredibly smooth surfaces and fine details that other technologies struggle to match. From dental applications to jewelry prototyping to high-end miniatures, SLA printing delivers professional results.
This guide covers everything you need to know about SLA printing - how it works, how it compares to other resin technologies (like MSLA and DLP), when to choose SLA over FDM, and the best SLA printers available today.
What is SLA Printing?
Stereolithography (SLA) is an additive manufacturing process that uses a UV laser to cure photosensitive liquid resin into solid plastic. Invented by Chuck Hull in 1984, it's the grandfather of all 3D printing technologies.
How SLA Printing Works
A UV laser beam is directed by mirrors (galvanometers) to trace out the cross-section of your model on the surface of liquid resin.
The laser's UV energy causes the photopolymer resin to solidify into a thin, precise layer.
The platform lowers (or raises, depending on design) by one layer height, and fresh resin flows over the cured layer.
The process continues layer by layer until the complete part is formed.
Key distinction: True SLA uses a laser that traces each layer point by point. This differs from MSLA (uses an LCD mask) and DLP (uses a projector) which cure entire layers at once.
SLA vs MSLA vs DLP: Understanding Resin Technologies
All three technologies use UV light to cure resin, but they do so in fundamentally different ways:
| Technology | Light Source | How It Works | Best For |
|---|---|---|---|
| SLA | UV Laser | Laser traces each layer point by point | Large parts, industrial, dental |
| MSLA | UV LEDs + LCD mask | LCD blocks light selectively, cures entire layer at once | Desktop printers, miniatures, affordable |
| DLP | UV Projector | Projector displays each layer, cures entire layer at once | Jewelry, dental, high detail |
SLA Advantages
- + Consistent detail across build area
- + Best for large parts
- + No pixel artifacts
- + Industrial proven reliability
MSLA Advantages
- + Much more affordable
- + Faster for small parts
- + Higher resolution LCDs available
- + Simpler mechanics
DLP Advantages
- + Very fast exposure times
- + Good for small detailed parts
- + No LCD degradation
- + Precise light control
Note: Most "resin printers" sold today are actually MSLA, not true SLA. The terms are often used interchangeably, but the technology is different. True SLA printers like Formlabs are generally more expensive but offer advantages for professional use.
SLA Printing vs FDM: When to Choose Each
| Factor | SLA Printing | FDM Printing |
|---|---|---|
| Surface Finish | Smooth, near-injection molded | Visible layer lines |
| Detail Resolution | Exceptional (25-50 microns) | Good (100-200 microns) |
| Part Strength | Good (varies by resin) | Excellent for functional parts |
| Material Cost | $30-150/L | $15-30/kg |
| Build Volume | Smaller typically | Larger options available |
| Post-Processing | Required (wash + cure) | Minimal |
| Safety | PPE required, ventilation needed | Generally safe |
| Ideal Use Cases | Miniatures, jewelry, dental, detailed prototypes | Functional parts, large objects, prototypes |
Choose SLA When:
- - Detail is critical (miniatures, figurines, jewelry)
- - Surface finish matters without post-processing
- - You need tight dimensional accuracy
- - Producing dental or medical models
- - Creating master patterns for molding
SLA Printing Materials
SLA-compatible resins offer a wide range of properties for different applications:
Standard Resins
General-purpose resins for prototyping and display models. Available in many colors including clear and translucent options.
Engineering Resins
Formulated for functional properties - heat resistance, impact resistance, flexibility, or high stiffness.
Specialty Resins
Burns out cleanly for jewelry casting. Zero ash residue.
Biocompatible, certified for surgical guides, dentures, retainers.
Stone-like finish for architectural models.
Static-dissipative for electronics applications.
Best SLA Printers (True Laser SLA)
True SLA printers using laser technology for professional results:
Formlabs Form 3+
The gold standard for desktop SLA. Low Force Stereolithography (LFS) technology delivers exceptional print quality with a huge material library. Reliable enough for production use.
Formlabs Form 3L
Large-format SLA for bigger parts and batch production. Same quality as Form 3+ with 5x the build volume. Two lasers for faster printing.
3D Systems SLA Printers
Industrial SLA from the company founded by the inventor of stereolithography. Production-grade machines for aerospace, automotive, and medical manufacturing.
Affordable MSLA Alternatives
If true SLA is outside your budget, these MSLA printers deliver excellent results at a fraction of the cost:
Elegoo Mars / Saturn Series
Popular hobbyist choice. Mars for small builds, Saturn for larger. Great value with active community support.
$200-500Anycubic Photon Series
Reliable entry-level printers with good software. Mono M3 and M5 offer excellent resolution at budget prices.
$200-600Phrozen Sonic Series
High-resolution LCDs in compact packages. The Sonic Mini 8K has exceptional detail for miniatures.
$300-800Creality Halot Series
Budget-friendly from the FDM giant. Good entry point with integrated features like air filtration.
$150-400SLA Post-Processing Workflow
All SLA/resin prints require post-processing before they're finished:
Use a plastic scraper at a low angle. Metal scrapers can damage the plate surface.
IPA (isopropyl alcohol) for standard resins. Some resins are water-washable. 2-5 minutes in wash station.
Air dry or use compressed air. Water spots will show after curing if not dried properly.
5-15 minutes in a curing station (or sunlight). Achieves full material properties and eliminates stickiness.
Clip with flush cutters after curing. Sand any remaining marks. Some prefer removing before full cure for easier cleanup.
SLA Printing Applications
Dental & Medical
Surgical guides, dental models, aligners, dentures, anatomical models for surgical planning. Biocompatible resins available.
Jewelry
Master patterns for casting, wax-like castable resins, direct metal printing patterns. Incredible detail for fine jewelry.
Product Design
High-fidelity prototypes that look like final products. Form studies, fit checks, client presentations.
Miniatures & Figurines
Tabletop gaming miniatures, collectible figures, display pieces. The detail level is unmatched by FDM.
Mold Making
Master patterns for silicone molds. Smooth surfaces reduce finishing work. Create production molds from printed masters.
Engineering
Precision prototypes, injection mold inserts, jigs and fixtures, wind tunnel models. Accurate for fit-testing.
Get SLA Prints Without Owning a Printer
SLA and resin printers produce outstanding results, but they require significant investment, space for safe operation, and ongoing maintenance. If you need SLA quality prints without the commitment, professional printing services are the answer.