When it comes to 3D printing, two technologies often come to mind: SLA and FDM. But how are they different, and which will be perfect for your needs? In this article, we’ll dive deep into the world of SLA and FDM 3D printing, comparing their strengths and weaknesses.
Spot the Difference: What are SLA and FDM?
SLA (Stereolithography) and FDM (Fused Deposition Modeling) are two popular 3D printing technologies that have revolutionized the way we make real-life objects from digital designs. While both technologies fall under the umbrella of additive manufacturing, there is a great difference between them in their printing processes, materials, and applications.
- SLA printing is like hardening the liquid resin with a precise laser beam, layer by layer.
- Imagine drawing each slice of your object with light in a pool of goo that transforms into solid plastic wherever the beam touches.
- FDM printing works like a precise hot glue gun, squeezing melted plastic through a moving nozzle
- Picture piping icing onto a cake, but the “icing” is hot plastic that quickly hardens into your desired shape.

Print Performance: Speed, Resolution, and Surface Finish
When choosing between SLA and FDM 3D printing technologies, it’s essential to consider the print performance factors that matter most for your project. Speed, resolution, and surface finish are three critical aspects that can significantly impact the quality, appearance, and lead time of your final product.
Print Performance | SLA | FDM |
---|---|---|
Speed | ★★★★☆ | ★★★★★ |
Resolution | ★★★★★ | ★★★☆☆ |
Surface Finish | ★★★★★ | ★★☆☆☆ |
Speed
Print speed is an important consideration, especially for time-sensitive projects or high-volume production. In general, SLA is able to achieve much faster print speeds compared to FDM, thanks to its laser-based curing process and the ability to print multiple parts simultaneously on the build platform.
SLA print speed: 170 mm/h max (depending on layer thickness and part geometry)
FDM print speed: 600 mm/s max (depending on layer thickness and part geometry)
Resolution
SLA typical layer thickness: 0.025-0.1 mm; minimum feature size: 0.2-0.5 mm
FDM typical layer thickness: 0.05-0.4 mm; minimum feature size: 0.8-2.0 mm
- Resolution in 3D printing signifies the amount of detail and accuracy that could be achieved. SLA is really remarkable in achieving high-resolution parts with fine features. The reason why SLA could reach a far higher resolution as compared to FDM is that it could employ a laser to cure liquid resin layer by layer.
- FDM, however, has a lower resolution due to the limitations of the extrusion process. Since the nozzle deposits the molten plastic layer by layer, the resulting parts will have more visible layer lines and a somewhat “stepped” appearance, especially on curved or angled surfaces.
Surface Finish
SLA (Left) vs FDM (Right)
- Another important factor concerning 3D-printed parts is surface finish. Parts printed with SLA usually have a smooth, almost glossy surface straight out of the printer. This is due to the fine layers and the liquid nature of the resin. Further improvements to this surface finish for SLA parts are possible through post-processing using sanding and polishing.
- FDM parts, in contrast, have a more textured surface finish because of the visible layer lines. The surface can be rough to the touch, especially on overhanging or curved areas. While the surface finish of FDM parts can be improved by simple post-processing methods like sanding or filling or vapor smoothing, truly smooth surfaces are rather difficult and time-consuming to get.
Application Arenas: Where SLA and FDM Excel
SLA and FDM each have their unique strengths and applications. While some projects can be achieved with either technology, others are better suited for one or the other.
Counting the Cost: Equipment, Material, and Ease of Use
When considering SLA and FDM 3D printing technologies for your project, it’s crucial to evaluate the associated costs and ease of use. In 3D printing, the overall cost encompasses not only the initial investment into equipment but also continued material and labor costs. Let’s break down these factors and compare how SLA and FDM stack up.
Cost | SLA | FDM |
---|---|---|
Printing Cost | More expensive (extra cost from post-processing tools) | More affordable |
Ease of Use | ★★★★★ | ★★★★★ |
Printing Cost
In terms of printing costs, FDM 3D printers are generally more affordable than SLA printers, both in terms of initial equipment investment and further expenses on materials.
Equipment Cost
- SLA 3D printers tend to be a little more expensive than FDM printers, with prices ranging from $200-$800 for entry-level models, while professional and prosumer models can cost anywhere from $3,000 to $10,000 or more.
- FDM 3D printers generally offer more budget-friendly options, with entry-level models starting around $150-$1,000, while professional-grade machines typically range from $2,000 to $5,000.
Material Cost
- SLA resins are typically more expensive than FDM filaments, with standard resins priced between $30-$50 per kilogram, while specialized resins (like dental, casting, or engineering grade) can range from $100 to $400 per kilogram.
- FDM filaments are relatively cheaper, with standard PLA and ABS priced around $20-$30 per kilogram, while specialized materials like carbon fiber-filled filaments can cost $40-$100 per kilogram.
For a more in-depth exploration of 3D printer costs, please refer to our dedicated article How Much Does a 3D Printer Cost?
Ease of Use
When considering the ease of use and labor requirements for SLA and FDM 3D printing, it’s essential to evaluate factors such as the learning curve, post-processing needs, and maintenance.
Learning Curve
- SLA 3D printing typically requires a steeper learning curve due to the need for careful resin handling, post-processing, and maintenance of the printer and its components.
- FDM 3D printing is normally perceived as more user-friendly and accessible, with a gentler learning curve and fewer complexities in the printing process.
Post-Processing
- SLA parts require post-processing, including cleaning the parts in isopropyl alcohol and post-curing them under UV light. However, some modern SLA 3D printers offer automated post-processing solutions, significantly reducing the time and labor involved.
- Most FDM parts have to be post-processed by hand, such as removing the supports, sanding, and other surface treatments. This is very time-consuming for complicated parts with intricate support structures.
Maintenance
- SLA 3D printers require regular maintenance, such as cleaning the resin tank, replacing the resin vat film, and ensuring proper calibration of the laser and build platform.
- FDM 3D printers generally have lower maintenance requirements, primarily involving cleaning the nozzle, ensuring proper bed leveling, and occasional lubrication of moving parts.
SLA vs FDM Comparison Table
SLA | FDM | |
---|---|---|
Illustration | ![]() | ![]() *Illustrated with Cartesian structure, the most common FDM configuration |
Full Name | Stereolithography | Fused Deposition Modeling |
Speed | ★★★★☆ | ★★★★★ |
Resolution | ★★★★★ | ★★★☆☆ |
Surface Finish | ★★★★★ | ★★☆☆☆ |
Printing Cost | More expensive | More affordable |
Ease of Use | ★★★★★ | ★★★★★ |
Typical Applications | Figurines Jewelry prototypes Dental models Miniatures Surgical guides | DIY projects Electronic cases Home decor Mechanical parts Functional parts |
Material | Varieties of resin (standard, engineering, etc.) | Standard thermoplastics (ABS, PLA, etc.) |
FAQ
Is SLA or FDM better for beginners?
FDM is generally considered more beginner-friendly due to its lower cost, wider material selection, and simpler post-processing.
Can I use both SLA and FDM printers for the same project?
Yes, you can combine parts printed with SLA and FDM to leverage the strengths of each technology, such as using SLA for detailed parts and FDM for larger, structural ones.
Which technology is more cost-effective, SLA or FDM?
Generally, FDM is cheaper for simple prototypes and larger prints due to cheaper printers, materials, and maintenance costs. However, SLA becomes more cost-effective in applications featuring highly detailed, smooth-surfaced models, which include small pieces with intricate details. Your specific needs and application will ultimately determine which technology provides better value.
Which technology is more eco-friendly, SLA or FDM?
FDM takes the lead in environmental friendliness. FDM uses recyclable plastic filaments, while SLA’s liquid resin requires special disposal and produces chemical waste from the alcohol used in cleaning. Additionally, SLA resins emit strong odors, requiring well-ventilated spaces for operation. However, both technologies can be environmentally responsible when materials are properly handled and disposed of.
What safety precautions should I take when using SLA or FDM printers?
Always operate your printer in a well-ventilated area, wear gloves when handling resins or hot materials, and follow the manufacturer’s guidelines for safe operation and material disposal.