Selective Laser Sintering

What is Selective Laser Sintering?

Selective laser sintering (SLS) is a powder bed printing technology. It uses a laser to fuse tiny bits of nylon powder, tracing the geometry of digitally sliced CAD models layer by layer and working from the bottom of the part upwards. 

Selective laser sintering (SLS) is an industrial 3D printing process that produces accurate - rapid prototypes and functional production parts in as fast as 1 day. Multiple nylon-based materials are available, which create highly durable final parts. 

SLS design guidelines will help you understand capabilities and limitations.

How Does Selective Laser Sintering Work?

The SLS machine begins sintering each layer of part geometry into a heated bed of nylon-based powder. After each layer is fused, a roller moves across the bed to distribute the next layer of powder. The process is repeated layer by layer until the build is complete.

When the build finishes, the entire powder bed with the encapsulated parts is moved into a breakout station, where it is raised up, and parts are broken out of the bed. An initial brushing is manually administered to remove a majority of loose powder. Parts are then bead blasted to remove any of the remaining residual powder before ultimately reaching the finishing department.

Why Choose Selective Laser Sintering For Your 3D Printing Project?

SLS is ideal to make functional parts that have greater toughness and higher impact strength than parts produced through stereolithography (SL). SLS lacks the surface finish and fine feature details available with SL. We also offer a number of secondary services such as painting, post machining and measurement and inspection, to further enhance the finish of your 3D-printed project design. 

SLS material data sheets can be found in our Material Comparison Guide


3DP icon logo
  • 1 to 50+ parts
  • Shipped in 1 to 7 working days
Common Applications
  • durable prototypes
  • functional, end-use parts
  • complex geometries


 

 

Watch: Which Technology for your Plastic Part?

Here at Protolabs we offer a variety of cutting-edge technologies to produce precision-engineered parts from a range of plastics, designed to suit your needs. From Multi Jet Fusion (MJF) to Selective Laser Sintering (SLS) to Stereolithography, we can create the parts you need quickly and precisely.

Plus, with our technical support team on call, we can talk to you about your designs and help you to choose the ideal production solution for your needs, and show you just what we can do to help you reach your creative vision.

Want to find out more about our cutting-edge plastic technologies? Watch this video.



 

 

Watch: Why is 3D Printing for me?

3D Printing is creating a whole new world of manufacturing, with the ability to create complex designs with quality and precision and deliver faster, more affordable results. Here at Protolabs we use the latest 3D printing technology, including stereolithography, selective laser sintering and direct metal laser sintering to build parts in resin, thermoplastics and metal.

When you need parts fast, 3D printing offers new possibilities for what you can do – simply send your designs online, and we can get parts shipped in as fast as a single day.

Watch this video to discover more about this exciting new technology.


Design Guidelines: Selective Laser Sintering




Selective Laser Sintering (SLS) Materials

PA 12 White

PA 12 White is an economical material choice for functional prototypes and end-use parts. It offers high impact and temperature resistance, is very durable, and remains stable under a range of environmental conditions. The nylon material exhibits a white finish with a slightly rougher surface texture compared to other nylons.

Primary Benefits​

  • Strength and stiffness
  • Well-balanced material properties
PA 11 Black

PA 11 Black provides excellent ductility and temperature resistance without sacrificing tensile strength. It offers one of the highest elongation break thresholds in the nylon family.

Primary Benefits​

  • High elongation at break
  • Flexibility
  • Uniform Black Colour
PA 12 40% Glass-Filled

PA 12 40% Glass-Filled is a polyamide powder loaded with glass spheres that add stiffness and dimensional stability. The material possesses higher thermal resistance than unfilled polyamides and exhibits excellent long-term wear resistance. Due to the glass additive, it has decreased impact and tensile strengths compared to other nylons.

Primary Benefits​

  • Stiffness and dimensional stability
  • Long-term wear resistance
  • High-temperature resistance

TPU-88A

This thermoplastic polyurethane (TPU) combines rubber-like elasticity and elongation with good abrasion and
impact resistance. It can be leveraged to produce both prototypes and functional parts.

Primary Benefits​

  • Flexibility
  • Tear and abrasion resistance
  • Durability
PA 12 Carbon Filled

PA 12 Carbon-Filled is an anthracite grey nylon characterized by extreme stiffness and high-temperature resistance, coupled with electric conductivity properties and lightweight. It can be used for both functional prototypes and end-use parts. The carbon-fiber filler provides different mechanical properties based on the considered three-axis direction. This material exhibits a good surface quality and smoother finish compared to other SLS nylons.

Primary Benefits​

  • Extreme stiffness
  • Electrical conductivity
  • Excellent long-term stability
PA 12 Flex

PA 12 Flex Black is a black / anthracite nylon characterised by excellent flexibility and impact resistance. PA 12 Flex Black combines positives properties of PA12 and PP. Strength and stiffness is similar to PA 12. The elongation is comparable to that of unfilled PP. Its high durability makes it an excellent choice not only for prototyping, but also for end-use parts.

Primary Benefits​

  • High elongation at break
  • Flexibility
  • Durability and toughness

Compare Material Properties

Material Colour Tensile Strength Tensile Modulus Elongation
PA 12 White
(PA 650)
White 50.0 Mpa 2,000 Mpa 11%
PA 11 Black
(PA 850)
Black 52 Mpa 1,800 Mpa 30%
PA 12 40% Glass-Filled
(PA 614-GS)
White 50 Mpa 3,600 Mpa 5%

These figures are approximate and dependent on a number of factors, including but not limited to, machine and process parameters. The information provided is therefore not binding and not deemed to be certified. When performance is critical, also consider independent lab testing of additive materials or final parts.


Benefits of Selective Laser Sintering

  • Competitively Priced
  • Very good accuracy of size and form
  • Suitable for some functional testing
  • Easily duplicates complex geometries

What is Selective Laser Sintering used for?

Selective Laser Sintering is used in a wide range of industries for a variety of products and purposes.

It is a popular choice in aerodynamic components, fans and smaller turbines. It is used in the automotive industry for interior components. For hinges, electrical housings and sports equipment.

Due to its range of materials with numerous properties it is also a popular choice in tubing for most industries; automotive, aerospace, medical, oil and gas.


Selective Laser Sintering Design Considerations

 

  • Add corner radii where walls meet to reduce stress
  • Uniform wall thickness between 1.5mm to 3.8mm, recommended to reduce in-build curl and potential for warping. Increases stability and accuracy.
  • Integrate ribs to reduce warping, on large flat areas
  • Where injection moulded parts can overmould metral bushings for threaded inserts, SLS can achieve comparable functionality via heat-stake inserts
  • Be careful when considering very fine text, minimum feature size is 1mm. Very small fonts tend to get jammed with powder making numbers and letters less legible. Moving to insert text provides better results, but is still limited to features no smaller than 0.5mm.
  • SLS has a large build frame and because there are no support structures involved, the entire bed can be utilised, making it easy to put multiple parts into a single build
  • Opt for unfilled Nylon, when more "give" is needed in the finished part
  • Identify cosmetic surfaces when submitting your design for quoting, technicians will often tip parts slightly in the build chamber to keep parts straight and true, but this can cause "stair stepping"
  • PA 11 Black - desirable for optical applications due to low reflectivity, also hides dirt, grease and grime.
  • PA 12 White - balanced, economical go-to material for general-purpose applications.
  • PA 12 40% Glass filled - good choice when stiffness and temperature resistance are required, but glass filler makes it brittle.
  • PA 12 Carbon filled - Many properties. Carbon-fibre filler provides different mechanical properties based on the considered three axis direction. Smoother finish compared to other SLS nylons and good surface quality.
  • TPU-88A - combines rubber-like elasticity and elongation with good abrasion and impact resistance. Can be leveraged to produce both prototypes and functional parts.
  • SLS materials tend to be Hydroscopic - absorb water

Resources

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