SLS 3D printing: laser sintering of powder

How SLS works

The printer spreads a thin layer of powder, a laser sinters it in the marked places and the platform drops by one layer. The process repeats until the part is finished. The unsintered powder stays around the part and holds it in place, which is why SLS needs no supports. At the end the part is lifted out of the block of powder and cleaned.

The typical material is polyamide, that is nylon. The surface is usually finely grainy and matt, and the parts are strong and cope well with load.

SLS compared with FDM

• Complex shapes. With no supports you can make cavities, channels and parts assembled inside each other.
• Strength. Parts are equally strong in every direction, whereas in FDM the bonds between layers are the weak point.
• Price. The machines and the powder are expensive, so SLS is typical of industrial services. FDM is cheaper for simple parts and smaller batches.
• Surface. It is grainy and never glossy, whereas FDM shows visible layers.

What this means for your order

We do not print SLS. We print with FDM in PLA and PETG. If you need something else, write to jakub.novak@boostello.com. We do not promise a print in advance, but we can advise.

If strength is what matters to you, it is often solved by orienting the part correctly, thicker walls and 40 % strong infill. We do not print nylon, so if you need exactly its properties, look for an SLS service. Of our materials the closest is PETG, which is tougher than PLA and takes impacts better.

How to recognise SLS on a finished part

You can spot an SLS part by its matt, slightly grainy surface and usually white or grey colour, which may need dyeing afterwards. Unlike filament printing there are no visible layer lines, just a fine texture like sandblasted plastic. Moving assemblies such as hinges or gears can be printed in one go without assembly, because the powder between the moving parts is blown out.

If you have seen a part like this somewhere and want something similar, for a visual model filament printing can often do the job too, only with visible layers.