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3D Printing Technology Comparison: FDM vs. SLA vs. SLS

Additive manufacturing, or 3D printing, lowers costs, saves time, and transcends the limits of fabrication processes for product development. From concept models and functional prototypes in rapid prototyping to jigs, fixtures, or even end-use parts in manufacturing, 3D printing technologies offer versatile solutions in a wide variety of applications.

Over the last few years, high-resolution 3D printers have become more affordable, easier to use, and more reliable. As a result, 3D printing technology is now accessible to more businesses, but choosing between the various competing 3D printing solutions can be difficult.

Which technology is suitable for your particular application? What materials are available? What equipment and training do you need to get started? How about costs and return on investment?

In this article, we’ll take a closer look at the three most established plastic 3D printing processes today: fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS).

Trying to decide between FDM and SLA 3D printers? Check out our in-depth FDM vs. SLA comparison.

FDM vs SLA vs SLS video guide
Video Guide

How to Choose a 3D Printing Technology

Having trouble finding the best 3D printing technology for your needs? In this video guide, we compare FDM, SLA, and SLS technologies across popular buying considerations.

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Infographic: Compare plastic 3D printing processes: selective laser sintering (SLS), fused deposition modeling (FDM) and stereolithography (SLA).

Download the high-resolution version of this infographic here.

Fused Deposition Modeling (FDM)

Fused deposition modeling (FDM), also known as fused filament fabrication (FFF), is the most widely used form of 3D printing at the consumer level, fueled by the emergence of hobbyist 3D printers. FDM 3D printers build parts by melting and extruding thermoplastic filament, which a printer nozzle deposits layer by layer in the build area.

FDM works with a range of standard thermoplastics, such as ABS, PLA, and their various blends. The technique is well-suited for basic proof-of-concept models, as well as quick and low-cost prototyping of simple parts, such as parts that might typically be machined.

FDM 3D print example

FDM parts tend to have visible layer lines and might show inaccuracies around complex features. This example was printed on a Stratasys uPrint industrial FDM 3D printer with soluble supports (machine starting at $15,900).

FDM has the lowest resolution and accuracy when compared to SLA or SLS and is not the best option for printing complex designs or parts with intricate features. Higher-quality finishes may be obtained through chemical and mechanical polishing processes. Industrial FDM 3D printers use soluble supports to mitigate some of these issues and offer a wider range of engineering thermoplastics, but they also come at a steep price.

FDM 3D printer part (left), compared to SLA 3D printer part (right).

FDM printers struggle with complex designs or parts with intricate features (left), compared to SLA printers (right).

Stereolithography (SLA)

Stereolithography was the world’s first 3D printing technology, invented in the 1980s, and is still one of the most popular technologies for professionals. SLA resin 3D printers use a laser to cure liquid resin into hardened plastic in a process called photopolymerization.

See how stereolithography works.

SLA 3D printed parts have the highest resolution and accuracy, the clearest details, and the smoothest surface finish of all plastic 3D printing technologies, but the main benefit of SLA lies in its versatility. Material manufacturers have created innovative SLA photopolymer resin formulations with a wide range of optical, mechanical, and thermal properties to match those of standard, engineering, and industrial thermoplastics. Resin 3D printing also offers the widest range of biocompatible materials.

SLA 3D printed part

SLA parts have sharp edges, a smooth surface finish, and minimal visible layer lines. This example part was printed on a Formlabs Form 3+ desktop SLA 3D printer (machine starting at $2,499).

SLA 3D printing is a great option for highly detailed prototypes requiring tight tolerances and smooth surfaces, as well as functional parts, such as molds, patterns, and end use parts. SLA is widely used in a range of industries from engineering and product design to manufacturing, dentistry, medicine, jewelry, model making, and education.

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Introduction to 3D Printing With Desktop Stereolithography (SLA)

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Selective Laser Sintering (SLS)

Selective laser sintering is the most common additive manufacturing technology for industrial applications, trusted by engineers and manufacturers across different industries for its ability to produce strong, functional parts.

See how selective laser sintering works.

SLS 3D printers use a high-powered laser to fuse small particles of polymer powder. The unfused powder supports the part during printing and eliminates the need for dedicated support structures. This makes SLS ideal for complex geometries, including interior features, undercuts, thin walls, and negative features. Parts produced with SLS printing have excellent mechanical characteristics, with strength resembling that of injection-molded parts.

SLS 3D printed part

SLS parts have a slightly rough surface finish, but almost no visible layer lines. This example part was printed on a Formlabs Fuse Series benchtop SLS 3D printer (machine starting at $24,999).

The most common material for selective laser sintering is nylon, a popular engineering thermoplastic with excellent mechanical properties. Nylon is lightweight, strong, and flexible, as well as stable against impact, chemicals, heat, UV light, water, and dirt. Other popular SLS 3D printing materials include polypropylene (PP) and the flexible TPU.

The combination of low cost per part, high productivity, and established materials make SLS a popular choice among engineers for functional prototyping, and a cost-effective alternative to injection molding for limited-run or bridge manufacturing.

sls example 3d printed part
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Introduction to Selective Laser Sintering (SLS) 3D Printing

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Compare FDM, SLA, and SLS 3D Printing Technologies

Each 3D printing technology has its own strengths, weaknesses, and requirements, and is suitable for different applications and businesses. The following table summarizes some key characteristics and considerations.

Fused Deposition Modeling (FDM)Stereolithography (SLA)Selective Laser Sintering (SLS)
Surface Finish★★☆☆☆★★★★★★★★★☆
Complex Designs★★★☆☆★★★★☆★★★★★
Ease of Use★★★★★★★★★★★★★★☆
ProsLow-cost consumer machines and materials
Fast and easy for simple, small parts
Great value
High accuracy
Smooth surface finish
Fast printing speeds
Range of functional applications
Strong functional parts
Design freedom
No need for support structures
ConsLow accuracy
Low details
Limited design compatibility
Sensitive to long exposure to UV lightRough surface finish
Limited material options
ApplicationsLow-cost rapid prototyping
Basic proof-of-concept models
Functional prototyping
Patterns, molds, and tooling
Dental applications
Jewelry prototyping and casting
Functional prototyping
Short-run, bridge, or custom manufacturing
Print VolumeUp to 300 x 300 x 600 mm (desktop and benchtop 3D printers)Up to 300 x 335 x 200 mm (desktop and benchtop 3D printers)Up to 165 x 165 x 300 mm (benchtop industrial 3D printers)
MaterialsStandard thermoplastics, such as ABS, PLA, and their various blends.Varieties of resin (thermosetting plastics). Standard, engineering (ABS-like, PP-like, flexible, heat-resistant), castable, dental, and medical (biocompatible). Pure silicone and ceramic.Engineering thermoplastics. Nylon 11, nylon 12, glass or carbon-filled nylon composites, polypropylene, TPU (elastomer).
TrainingMinor training on build setup, machine operation, and finishing; moderate training on maintenance.Plug and play. Minor training on build setup, maintenance, machine operation, and finishing.Moderate training on build setup, maintenance, machine operation, and finishing.
Facility RequirementsAir-conditioned environment or preferably custom ventilation for desktop machines.Desktop machines are suitable for an office environment.Workshop environment with moderate space requirements for benchtop systems.
Ancillary EquipmentSupport removal system for machines with soluble supports (optionally automated), finishing tools.Washing station and post-curing station (both can be automated), finishing tools.Post-processing station for part cleaning and material recovery.

3D Printing Costs and Return on Investment With FDM, SLA, and SLS Technologies

Ultimately, you should choose the technology that makes the most sense for your business. Prices have dropped significantly in recent years, and today, all three technologies are available in compact, affordable systems.

Calculating 3D printing costs does not end with upfront equipment costs. 3D printing material and labor costs have a significant influence on cost per part, depending on the application and your production needs.

Here’s a detailed breakdown by technology:

Fused Deposition Modeling (FDM)Stereolithography (SLA)Selective Laser Sintering (SLS)
Equipment CostsBudget printers and 3D printer kits start at a few hundred dollars. Higher quality mid-range desktop printers start around $2,000, and industrial systems are available from $15,000.Professional desktop printers start at $2,499, large-format benchtop printers at $8,999, and large-scale industrial machines are available from $80,000.Benchtop industrial systems start at $24,999, and traditional industrial printers are available from $100,000.
Material Costs$50-$150/kg for most standard and engineering filaments, and $100-200/kg for support materials.$149-$200/L for most standard and engineering resins.$100/kg for nylon. SLS requires no support structures, and unfused powder can be reused, which lowers material costs.
Labor NeedsManual support removal (can be mostly automated for industrial systems with soluble supports). Lengthy post-processing is required for a high-quality finish.Washing and post-curing (both can be mostly automated). Simple post-processing to remove support marks.Simple cleaning to remove excess powder.
3d printing cost

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3d printing technology comparison FDM printer vs SLA printer vs SLS printer

Prototypes of a ski goggles' frame printed with FDM, SLA and SLS technology (from left to right).

We hope this article has helped you focus your search for the best 3D printing technology for your application.

Explore our additional resources to master the intricacies of 3D printing, and dive deeper into each technology to learn more about specific 3D printing systems.