Summary of Selective Laser Sintering (SLS) materials and process

Selective laser sintering (SLS) is an industrial 3D printing process that produces accurate prototypes and functional production parts in as fast as 1 day. Multiple nylon-based materials and a thermoplastic polyurethane (TPU) are available, which create highly durable final parts that require heat resistance, chemical resistance, flexibility, or dimensional stability. With SLS 3D printing, no support structures are required making it easy to nest multiple parts into a single build and an economical solution for when higher volumes of 3D-printed parts are required.

How Does SLS 3D Printing Work?
Printing: The powder is dispersed in a thin layer on top of a platform inside of the build chamber. The printer preheats the powder to a temperature somewhat below the melting point of the raw material, which makes it easier for the laser to raise the temperature of specific regions of the powder bed as it traces the model to solidify a part. The laser scans a cross-section of the 3D model, heating the powder to just below or right at the melting point of the material.

This fuses the particles together mechanically to create one solid part. The unfused powder supports the part during printing and eliminates the need for dedicated support structures. The platform then lowers by one layer into the build chamber, typically between 50 to 200 microns, and the process repeats for each layer until parts are complete.

Cooling: After printing, the build chamber needs to slightly cool down inside the print enclosure and then outside the printer to ensure optimal mechanical properties and avoid warping in parts.

Post-processing: The finished parts need to be removed from the build chamber, separated, and cleaned of excess powder. The powder can be recycled and the printed parts can be further post-processed by media blasting or media tumbling.

Why choose Selective Laser Sintering?

With no need for support structures, this technology is suitable for interlocking parts, moving parts, living hinges and other highly complex designs. Whether you need fully functional prototypes or a series of complex end-use parts, Laser Sintering’s design freedom serves both. Besides, we make production fast and cost-effective for you by maximizing the available build space in each machine.

SLS Material Properties & Uses
Our SLS materials include a wide range of advanced nylon and composite materials consisting of superfine particles <100 nm in diameter.
The materials available for SLS enable uses ranging from impact-resistant plastics to styrene-based options that are great for plaster and metal castings. SLS is frequently chosen for low- to mid-volume end-use parts like enclosures, snap-fit parts, automotive moldings, and thin-walled ducting.

Some of our SLS engineering plastics are made with flame-retardant materials, enabling them to answer aircraft and consumer product requirements. Glass-filled materials are also available, offering greater stiffness and heat resistance, as well as fiber-reinforced plastic for ultimate stiffness. SLS also includes material options on the other end of the spectrum, for rubber-like flexible parts, enabling applications like hoses, gaskets, grip padding, and more.

Nylon/PA 12
Strong polyamide 12 thermoplastics that can replace traditionally injection molded articles; includes food-grade, medical-grade, and flame-retardant capable options.

Filled Nylons/PA
Engineered for greater end-use part performance, these materials are developed with glass, aluminum, or mineral fiber fillers to offer a range of advanced properties in terms of stiffness, temperature resistance, strength, and surface finish.

Nylon/PA 11
Impact-resistant polyamide 11 thermoplastics that offer molded-part performance in harsh environments; ideal for snap-fits and living hinges with the flexibility to bounce back to the original shape.

Elastomeric Thermoplastics
Rubber-like flexibility for prototypes and production parts with excellent memory, tear, and abrasion resistance.

Castable Polystyrene
Great for sacrificial patterns for prototype metal castings and low to medium production runs without tooling.

Benefits & Limitations of SLS
The key advantages and disadvantages of the technology are summarised below:
SLS parts have good, isotropic mechanical properties, making them ideal for functional parts and prototypes.
SLS requires no support, so designs with complex geometries can be easily produced.
The manufacturing capabilities of SLS is excellent for small to medium batch production.
Only industrial SLS systems are currently widely available, so lead times are longer than other 3D printing technologies, such as FDM and SLA.
SLS parts have a grainy surface finish and internal porosity that may require post processing, if a smooth surface or watertightness are required.
Large flat surfaces and small holes cannot be printed accurately with SLS, as they are susceptible to warping and oversitnering.

SLS 3D Printing Applications

SLS 3D printing accelerates innovation and supports businesses across a wide range of industries, including engineering, manufacturing, and healthcare.

General
Complex and durable prototype and production parts
Parts with snap fits/living hinges
Automotive design
Aerospace parts and ducting, flame-retardant parts
Low-volume production and mass customization solutions
Medical devices
Elastomeric and urethane parts, such as gaskets, seals and hoses
Functional proof-of-concept and design evaluation models
Wind-tunnel test models

Rapid Manufacturing
Aerospace hardware
Medical and healthcare
Electronics; packaging, connectors
Homeland security
Military hardware

Tooling and Patterns
Jigs, fixtures and tools
Casting patterns

Production
Short run end-use components
Complex plastic parts
Part consolidation exercises