selective laser sintering process - Understanding SLS models

The selective laser sintering process builds SLS models using STL files created from a 3D cad design.

 

The basic material consists of powder with particle sizes of around 50 µm which are successively spread in layers on top of each other. A computer controlled CO2 laser beam scans the surface & selectively binds together the relevant particles to make the SLS model.

 

During laser exposure, the powder temperature rises above the glass transition point causing the adjacent particles to flow together - this process is called sintering  As the powder is solid, it is self-supporting, so unlike the SLA process, supports aren't necessary for SLS models.

Free help with selective laser sintering process - notes & examples of SLS models

When considering using the selective laser sintering process please bear in mind the following :-

1. The standard accuracy of SLS models is ± 0.2% / ± 0.2mm, but higher accuracy can be achieved.
2. The minimum wall thickness is 1 mm, but living hinges are possible with SLS models at 0.3 mm.
3. The selective laser sintering process creates SLS models which typically have a grainy surface with acceptable roughness. For aesthetic & part evaluation models, the stereolithography process is more suitable.
4. PA SLS models can be used for functional tests - snap fits, living hinges, thermal & mechanical loads.
   Glass filled PA SLS models are suitable for functional tests with high thermal resistance & impact strength.
   PS SLS models can be used to make lost wax models for investment casting.
   After PU impregnation, 80 Shore A TPE SLS models are watertight & can withstand a wide range of liquids. SLS models have mechanical properties comparable to injection moulded PA12 parts.  
   Key: PA = Polyamide  PS = Polystyrene  TPE = Thermoplastic Elastomer
5. Although dimensions aren't limited, SLS models may be made of several sub-parts.