SLS vs FDM vs SLA: 3D Printing Technology Comparison

Choosing the right 3D printing technology is crucial for project success. This comprehensive comparison of SLS, FDM, and SLA helps you understand which technology best fits your needs.

Technology Overview

SLS (Selective Laser Sintering)

Uses a high-powered laser to fuse thermoplastic powder particles layer by layer. Parts are self-supporting within the powder bed, enabling complex geometries without support structures.

FDM (Fused Deposition Modeling)

Extrudes molten thermoplastic filament through a heated nozzle, building parts layer by layer. Requires support structures for overhangs and complex geometries.

SLA (Stereolithography)

Uses a UV laser or projector to cure liquid photopolymer resin layer by layer. Produces smooth surfaces but requires support structures and extensive post-processing.

Part Strength Comparison

Mechanical Properties

Winner: SLS

SLS parts exhibit isotropic properties with strength comparable to injection molding. PA12 offers 48 MPa tensile strength with excellent durability. FDM parts are anisotropic with weaker layer adhesion. SLA parts are often brittle and degrade under UV exposure.

Surface Quality

Surface Finish

Winner: SLA

SLA produces the smoothest surfaces with minimal layer lines. SLS offers good surface finish with slight texture. FDM shows visible layer lines requiring significant post-processing.

Design Freedom

Complex Geometries

Winner: SLS

SLS requires no support structures, enabling nested assemblies, internal channels, and organic shapes. FDM and SLA both require supports that limit design freedom and add post-processing time.

Cost Comparison

Equipment Cost

FDM printers start at low cost points. Desktop SLS like SinterX brings industrial technology at mid-range pricing. SLA systems span both low-cost and high-end professional ranges.

Per-Part Costs

For functional parts, SLS often offers the best value through material efficiency and no support waste. FDM is economical for simple parts. SLA costs add up with resin consumption and post-processing labor.

Decision Matrix

Choose SLS When You Need

Functional parts with excellent mechanical properties, complex geometries without support limitations, production-quality materials and finish, and material efficiency through recycling.

Choose FDM When You Need

Low initial investment, large build volumes, simple geometries, and basic prototyping.

Choose SLA When You Need

Highest surface quality and detail, visual appearance models, jewelry casting patterns, and smooth translucent parts.

Conclusion

Each technology has strengths for specific applications. SLS offers the best combination of functionality, design freedom, and material performance for professional manufacturing.