Introduction
Selective Laser Sintering is the Additive manufacturing technique in which light energy is used to sinter powdered plastic into solids to produce models .
It is very effective and produces parts with high level of accuracy , dimensional stability and design reproduction .
It is used for both prototyping of functional polymer components and for small production runs.
It offers very high design freedom , great accuracy and produces parts with good and consistent mechanical properties when compared to FDM and SLA.
Design Guidelines
For making componants using SLS technology it is very important to know how to design the componants , such that the design is 100% printable .
Hence by following these guidelines your model will have less chances of failing during the process.
Design Considerations For SLS Printing:
1. Minimum Wall Thickness : 1mm
To avoid failure and increase strength and rigidity of the part the recommended thisckness is 1mm but for living hinges it could be 0.3mm
2.Warp
It is necessary to avoid printing very flat surfaces as they will lead to warping, even ribs will not prove helpful in such cases.
3.Smoothening
Minimum dimension 30mm
Maximum dimension 300mm with wall thickness of 1mm
When the componants are put into the tumbler to be smoothened care must be taken that , during the the process parts shouldn’t get destroyed or get stuck inside the smoothening cylinder. Therefore for parts which need smoothening these parameters need to be checked
4. Interior Polishing Minimum Diameter : 6.5mm
While polishing interior surfaces the grains may get stuck if the profile is smaller than 6.5 mm in diameter.
Hence care must be taken to ensure surfaces exposed to polishing exceeds 6.5 mm in diameter.
5.Clearance
Moving parts : 0.5mm
Assembly parts : 0.6mm
6. Minimum Boss Height : 4.5 mm
For any Embossing purposes the minimum height to which it must be embossed is 4.5mm , with a line thickness of 1mm
7. Minimum Hole Diameter : 1mm
During the operation the particles inside the holes will be exposed to temperatures that can cause the particles to solidy , thereby disprotionating the hole .
Hence a minimum hole diameter of 1mm needs to be provided.
8.Fillet
All sharp edges need to be filleted to ensure proper polishing and sealing purposes. This also ensures that the stress concentration is at minimum and leads to better product life.
Conclusion
In order to effectively print using SLS these guidelines need to be followed and implemented in the design.