Selective Laser Sintering (SLS)

Max Dimensions

Layer Thickness

Minimum Feature Size

* PA 12 Smooth White

** PA 12 Carbon Filled Smooth Black, PA 12 Flex Pure Black

*** TPU-88A Pure Black

PA 12 Smooth White
PA 12 Vapour Smooth White
PA 12 - Carbon Filled Smooth Black
PA 12 Flex Pure Black
TPU-88A Pure Black

Selective laser sintering (SLS) is a powder bed printing technology. It uses a high powered 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.

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

SLS parts 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

The components of a SLS 3D printer include: laser unit (1), laser beam (2), mirror/galvo motor system, beam steering (3), focused & directed beam (4), build chamber (5), manufactured part (6), roller (7), powder supply container (8), pistons (9), and powder collection container (10).

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.

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

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.

• 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. 
• If your geometry has a thick area (> 4 mm), as a rule, hollowing out the part to a wall thickness of 2 to 4 mm will be required, to avoid sink marks or even a machine crash. Protolabs will modify the CAD file. Un-sintered powder will remain within the hollowed-out part and cannot be removed.
• 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 12 Smooth White - balanced, economical go-to material for general-purpose applications.
• PA 12 - Glass Filled Smooth White - good choice when stiffness and temperature resistance are required, but glass filler makes it brittle.
• PA 12- Carbon Filled Smooth Black - 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 Pure Black - 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