Selective Laser Sintering (SLS) is an industrial 3D printing method that creates precise prototypes and functional production parts in as little as one day. It offers a range of nylon-based materials and thermoplastic polyurethane (TPU) that produce highly durable final parts with properties like heat resistance, chemical resistance, flexibility, and dimensional stability. Since SLS does not require support structures, it allows for easy nesting of multiple parts in a single build, making it a cost-effective solution for producing higher volumes of 3D-printed parts.

Typical applications of SLS include:

  • Jigs and fixtures
  • Housings
  • Snap fits and living hinges

Why Choose SLS?

Discover how SLS utilizes real thermoplastic and elastomeric materials to create parts with excellent mechanical properties. The final parts are ideal for testing future injection molding designs or for use as functional, end-use components.

Vapor Smoothing is Now Available!

Vapor smoothing is now offered for select 3D-printed nylon parts. This process smooths out rough surfaces, leaving parts with a glossy, visually appealing finish.

Learn More

Design Guidelines for Selective Laser Sintering (SLS)

Our essential guidelines for selective laser sintering highlight key design factors that improve part manufacturability, enhance the visual appearance, and shorten overall production time.

US Metric
Nylon and TPU Materials 12.6 in. x 10.6 in. x 16 in. 304mm x 269mm x 406mm
PP (Polypropylene) 12.6 in. x 10.6 in. x 10.6 in. 304mm x 269mm x 269mm
PA12 19 in. x 19 in. x 17 in. 482mm x 482mm x 431mm
US Metric
Nylon and TPU Materials 12.6 in. x 10.6 in. x 16 in. 304mm x 269mm x 406mm
PP (Polypropylene) 12.6 in. x 10.6 in. x 10.6 in. 304mm x 269mm x 269mm
PA12 19 in. x 19 in. x 17 in. 482mm x 482mm x 431mm
US Metric
Minimum Wall Thickness 0.030 in. 0.762mm
US Metric
Nylons 0.03 in. 0.762mm
PP and TPU 0.04 in. 1.01mm

SLS Tolerances

For properly designed parts, tolerances of ±0.010 in. (0.25mm) along with 0.1% of the nominal length are typically achievable. However, tolerances may vary depending on the geometry of the part.

SLS Part Warpage

Parts with larger dimensions (>7 in.) and thin features are more prone to warping. To ensure stability, we recommend maintaining a consistent thickness of 0.125 in. (3.175mm).

Standard Bead blast to remove all powder, which leaves a consistent overall texture.
Vapor Smoothing Significant reduction of surface roughness from 250+ μin RA (as-printed) to 64 – 100 μin RA (after smoothing). Available for PA11 Black.
Custom Secondary options include a primer or dye color that can be applied as well as taps and inserts.
Standard Bead blast to remove all powder, which leaves a consistent overall texture.
Vapor Smoothing Significant reduction of surface roughness from 250+ μin RA (as-printed) to 64 – 100 μin RA (after smoothing). Available for PA11 Black.
Custom Secondary options include a primer or dye color that can be applied as well as taps and inserts.
Standard Bead blast to remove all powder, which leaves a consistent overall texture.
Vapor Smoothing Significant reduction of surface roughness from 250+ μin RA (as-printed) to 64 – 100 μin RA (after smoothing). Available for PA11 Black.
Custom Secondary options include a primer or dye color that can be applied as well as taps and inserts.

Materials for Selective Laser Sintering (SLS)

PA 11 Black (PA 850) offers a combination of flexibility and ductility while maintaining strong tensile strength and temperature resistance. These qualities make PA 850 a versatile material for functional and dynamic parts.

Key Benefits

  • Best elongation at break among all 3D-printed nylons
  • Consistent deep-black color that enhances part features and provides a polished look

PA12 Black offers excellent mechanical properties and chemical resistance, making it perfect for functional parts and prototypes.

Key Benefits

  • Superior isotropic mechanical properties
  • Cost-effective material choice

PA 12 White (PA 650) is a versatile material ideal for general-purpose applications such as functional and end-use parts. It is the strongest among unfilled nylon materials and offers slightly higher stiffness compared to PA 11 Black.

Key Benefits

  • Cost-effective material option
  • High strength and rigidity

PA12 40% Glass-Filled (PA614-GS) is a nylon powder enhanced with 40% glass spheres, which provides increased stiffness and excellent dimensional stability. This material is ideal for applications that demand long-term wear resistance. However, due to the glass content, it has lower impact and tensile strength compared to other nylon-based materials.

Key Benefits

  • Excellent wear resistance over time
  • Enhanced stiffness

Polypropylene Natural provides exceptional chemical resistance, making it one of the top choices among SLS and MJF materials. This material is both tough and durable while maintaining flexibility, and it is resistant to most acids. Additionally, it is a lightweight option.

Key Benefits

  • Excellent chemical resistance
  • Lightweight and durable

TPU 70-A is a white thermoplastic polyurethane known for its rubber-like flexibility and elongation, as well as its strong abrasion and impact resistance. This material is perfect for applications such as seals, gaskets, grips, hoses, or any part requiring superior resistance under dynamic loading conditions.

Key Benefits

  • Excellent elongation at break
  • High flexibility

Compare Material Properties

Material Color Tensile Strength Tensile Modulus Elongation
PA 11 Black (PA 850) Black 7.54 ksi 261 ksi 30%
PA 12 Black Dyed Black 6.7 ksi 276 ksi 13%
PA 12 White (PA 650) White 7.25 ksi 290 ksi 11%
PA12 Value Off White 6.7 ksi 276 ksi 13%
PA 12 Mineral-Filled (Duraform HST) Light Gray 5.51 ksi 450 ksi 3%
PA 12 40% Glass-Filled (PA 614-GS) White 7.25 ksi 522 ksi 5%
Polypropylene Natural Natural 2.61 ksi 123 ksi 15%
TPU 70-A White 580 psi 210%
Material Color Tensile Strength Tensile Modulus Elongation
PA 12 White (PA 650) White 50.0 MPa 2,000 MPa 11%
PA12 Black Black 46 MPa 1,900 MPa 13%
PA 11 Black (PA 850) Black 52 MPa 1,800 MPa 30%
PA12 Value Off White 46 MPa 1,900 MPa 13%
PA 12 Mineral-Filled (Duraform HST) Light Gray 38 MPa 3,100 MPa 3%
PA 12 40% Glass-Filled (PA 614-GS) White 50 MPa 3,600 MPa 5%
Polypropylene Natural Natural 18 MPa 848 MPa 15%
TPU 70-A White 4.0 MPa 210%

These values are estimates and can vary based on several factors, such as machine settings and process conditions. As such, the information provided is not legally binding or guaranteed. For critical performance requirements, it is recommended to conduct independent testing of the additive materials or finished parts.

Surface Finish of SLS Parts

The surface finish of SLS parts tends to be rougher than that of parts produced by other 3D printing technologies, typically ranging from 100-250 RMS. To enhance the finish, most parts are bead blasted to remove any remaining loose powder and achieve a smooth matte surface. For PA11 Black parts, vapor smoothing is a post-processing option available, which results in a surface roughness between 64 – 100 μin RA.

Material: PA12 40% Glass-Filled (PA614-GS)

Resolution: Normal (0.004 in. layer thickness)

Finish: Standard

Material: PA11 Black (PA850)

Resolution: Normal (0.004 in. layer thickness)

Finish: Standard

Our SLS 3D Printers

We utilize advanced SLS technology, including the sPro140 machines, which offer the largest sintering build volume in the world. These machines are equipped with fully digital, high-speed scanning systems, ensuring exceptional process consistency. Their closed systems for powder blending and delivery guarantee reliable part quality. Additionally, we use sPro60 machines, designed for high throughput and compatible with a variety of materials.

How SLS 3D Printing Works

The SLS process begins with the machine sintering each layer of the part’s geometry onto a heated bed filled with nylon-based powder. Once a layer is fused, a roller spreads the next layer of powder across the bed. This process continues, layer by layer, until the part is fully built.

After the build is completed, the entire powder bed containing the parts is transferred to a breakout station, where it is elevated, and the parts are carefully removed. A manual brushing process is first used to eliminate most of the loose powder. The parts are then bead blasted to remove any remaining powder residue before moving on to the finishing stage.

Explore Our 3D Printing Facility

Take a virtual tour of our state-of-the-art additive manufacturing facility in North Carolina, one of the largest 3D printing operations globally. See firsthand how we produce high-quality prototypes as well as fully functional end-use components and assemblies.

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