The Selective Laser Sintering (SLS) process uses a laser to build parts by sintering (fusing) powdered material layer by layer from the bottom up. SLS parts can be accurate and more durable than SLA parts, but the finish is relatively poor with a grainy or sandy feel. There is reduced strength between the fused particles, so the parts will tend to be weaker than machined or molded parts made from the same resin. In addition, there are very few resins available in the powdered form that is required for SLS.
Pros: SLS Parts tend to be more accurate and durable than SLA parts. The process can make parts with complex geometries.
Cons: The parts have a grainy or sandy texture and are typically not suitable for functional testing due to their reduced mechanical properties. While SLS can make parts with complex geometries, it gives no insight into the eventual manufacturability of the design.