What is SLS printing?
SLS 3D printing, or Selective Laser Sintering, is an advanced additive manufacturing technology that uses a high-powered laser to fuse powdered material—typically nylon—into solid parts, layer by layer. Unlike filament or resin-based methods, SLS printing requires no support structures, as each layer is embedded in loose powder that naturally holds the shape during the build process. It’s a go-to solution for producing strong, functional prototypes and end-use components with complex geometries.
What is SLS in 3D printing?
SLS in 3D printing refers specifically to the use of a laser to sinter powdered thermoplastic materials — a process that sets it apart from melting (as in metal printing) or curing (as in SLA). Because SLS doesn’t require support structures, designers have much greater freedom to create internal features, organic forms, and nested assemblies—all in a single print job.
How does SLS printing work?
The SLS 3D printing process begins with a thin layer of polymer powder spread evenly across a heated build chamber. A laser then selectively scans the cross-section of the object, fusing the powder where the part should solidify. Once a layer is complete, the build platform lowers slightly, and a new layer of powder is applied. This cycle repeats until the part is fully formed inside a block of unsintered powder, which is later removed during depowdering.
This technology delivers excellent mechanical properties and high dimensional accuracy, making it ideal for engineering-grade applications.
What is an SLS printer?
An SLS printer—also called an SLS printing machine—is a professional-grade 3D printer designed to handle powdered materials like PA12, PA11, or flexible TPUs. It consists of a powder management system, recoating blade, laser scanning system, and a temperature-controlled build chamber. SLS printers come in various sizes, from compact benchtop models to large-format industrial systems.
They are widely used in sectors such as automotive, aerospace, consumer electronics, and medical device manufacturing.
Can SLS print metal?
Standard SLS printing is not designed for metal. However, metal 3D printing processes such as DMLS (Direct Metal Laser Sintering) and SLM (Selective Laser Melting) are based on similar principles. These use a comparable powder bed fusion method but operate at much higher temperatures with different laser types. So while an SLS printer itself can’t print metal, the overall powder bed fusion family of technologies absolutely includes metal-compatible systems.
SLS 3D printing diagram (visual explanation)
While we can’t show a diagram here directly, a typical SLS 3D printing diagram would include the following components:
- powder feed system,
- recoating blade,
- build platform,
- laser scanning unit,
- heated chamber,
- powder bed.
The diagram helps visualize how each layer is selectively fused by the laser within the bed of powder, and how the part is later removed from the unsintered surroundings.
Why choose SLS printing?
SLS offers a unique combination of material performance, design freedom, and production-grade results. It’s one of the few 3D printing technologies capable of producing complex, durable, and precise parts without any support material—making it both efficient and cost-effective for small to medium batch production.
Whether you’re developing functional prototypes, spare parts, or end-use components, SLS 3D printing technology gives you industrial capabilities in a compact, additive workflow.
SLA vs SLS 3D printing
While both SLA and SLS are considered high-precision 3D printing technologies, they differ significantly in materials, applications, and operational needs. SLA (Stereolithography) uses a light source to cure liquid resin into highly detailed parts with smooth surfaces, making it ideal for visual prototypes, dental models, and intricate designs. SLS (Selective Laser Sintering), on the other hand, works with powdered thermoplastics to produce strong, functional parts with excellent mechanical properties—without requiring support structures. SLA is best suited for aesthetic and small-scale applications, while SLS excels in industrial-grade, performance-driven use cases where strength and durability are key.
| Feature | SLA (Stereolithography) | SLS (Selective Laser Sintering) |
|---|---|---|
| Material type | Liquid photopolymer resin | Thermoplastic powder (e.g., PA12, PA11) |
| Support structures | Required | Not required (powder acts as support) |
| Surface finish | Very smooth | Matte, slightly rough |
| Detail and resolution | Extremely high (excellent for fine features) | High, but slightly less detailed than SLA |
| Mechanical strength | Moderate | High (suitable for functional parts) |
| Post-processing | Requires cleaning and UV curing | Requires depowdering |
| Design freedom | Limited by support requirements | Excellent (supports complex and nested geometries) |
| Best for | Prototypes, dental, jewelry, visual models | Prototypes, end-use parts, mechanical components |
| Printer maintenance | Medium (resin handling and cleaning) | Higher (powder handling, temperature control) |
| Common industries | Dental, medical, design, education | Aerospace, automotive, consumer products, engineering |
Explore also
Related categories
3D printing process
Materials for 3D printing
Design for 3D printing
