SLS is one of the newer AM technologies and has developed acclaimed for enhanced design freedom and its usefulness for rapid prototyping and low volume production.
Selective laser sintering (SLS) features the sintering of powdered material – most typically nylon or or polyamide (PA), or nylon blend like glass-fibre nylon or alumide by way of a laser. The laser is guided by way of CAD/CAM software to incrementally build an object, layer by layer. It belongs in the family of powder bed fusion technologies like selective laser melting, with the major difference being intensity of technical details and the fact that it fuses polymers.
HOW SLS WORKS
- The powder bin and the build area are first heated just below the melting temperature of the polymer and a recoating blade spreads a thin layer of powder over the build platform.
- A laser then scans the contour of the next layer and selectively sinters (fuses together) the particles of the polymer powder. The entire cross section of the component is scanned, so the part is built solid.
- When the layer is complete, the build platform moves downwards and the blade re-coats the surface. The process then repeats until the whole part is complete.
- The parts are fully encapsulated in the unsintered powder upon completion, and the powder bin must cool down before the parts can be removed. Since there is considerable heat, and it is essentially insulated by the powder, the process can take a considerable amount of time (up to 12 hours). The parts are then cleaned with compressed air or other blasting media and are ready to use or further post process.
- The remaining unsintered powder is collected and can be reused.
SLS parts offer:
- SLS parts have good, isotropic (identical on all axis) mechanical properties, making them ideal as functional parts and prototypes.
- One of the key benefits to SLS 3D printing is design freedom. This is partly because the powder used in the sintering process acts to remove the need for support structures during the building process.
- Like SLA, SLS printers do not require belt driven, gantry mounted extruder heads and tends to print much more rapidly than other methods like FDM.
- Porosity good: SLS printed parts often end up with porosity which can be used to dye or treat final parts more easily than FDM or SLA parts
- Only industrial SLS systems are currently widely available, so lead times are longer than other 3D printing technologies, such as FDM and SLA.
- Porosity Bad: SLS parts have a grainy surface finish and internal porosity that may require further post processing if a smooth surface or water seal is needed.
- Large flat surfaces and small holes cannot be printed accurately with SLS, as they are susceptible to warping and over-sintering.
SLS really shines when you need 3D plastic parts that will last. While parts created by other additive manufacturing methods may become brittle over time, SLS 3D printers are capable of producing highly durable parts for real-world 3D prototyping and mold making. And because SLS parts are so robust, they rival those produced in traditional manufacturing methods and are already used in a variety of end-use applications, such as:
- Complex geometric parts
- Heat, flame and chemically resistant
- Parts that require impact resistance
- Living hinges or snaps
- Aerospace parts or ducting
- Medical and healthcare applications
- Automotive components
- UAV and UAS components
SLS 3D PRINTERS
i3D is proud to welcome the Eplus3D EP-P3850 and EP-P420 SLS Selective Laser Sintering printers.